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* perf mem: Support using -f to override perf.data file ownershipYunlong Song2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable perf mem to use perf.data when it is not owned by current user or root. Example: # perf mem -t load record ls # chown Yunlong.Song:Yunlong.Song perf.data # ls -al perf.data -rw------- 1 Yunlong.Song Yunlong.Song 16392 Apr 2 14:34 perf.data # id uid=0(root) gid=0(root) groups=0(root),64(pkcs11) Before this patch: # perf mem -D report File perf.data not owned by current user or root (use -f to override) # perf mem -D -f report Error: unknown switch `f' usage: perf mem [<options>] {record|report} -t, --type <type> memory operations(load,store) Default load,store -D, --dump-raw-samples dump raw samples in ASCII -U, --hide-unresolved Only display entries resolved to a symbol -i, --input <file> input file name -C, --cpu <cpu> list of cpus to profile -x, --field-separator <separator> separator for columns, no spaces will be added between columns '.' is reserved. As shown above, the -f option does not work at all. After this patch: # perf mem -D report File perf.data not owned by current user or root (use -f to override) # perf mem -D -f report # PID, TID, IP, ADDR, LOCAL WEIGHT, DSRC, SYMBOL 39095 39095 0xffffffff81127e40 0x016ffff887f45148338 8 0x68100142 /proc/kcore:perf_event_aux 39095 39095 0xffffffff8100a3fe 0xffff89007f8cb7d0 6 0x68100142 /proc/kcore:native_sched_clock 39095 39095 0xffffffff81309139 0xffff88bf44c9ded8 6 0x68100142 /proc/kcore:acpi_map_lookup 39095 39095 0xffffffff810f8c4c 0xffff89007f8ccd88 6 0x68100142 /proc/kcore:rcu_nmi_exit 39095 39095 0xffffffff81136346 0xffff88fea995dd50 6 0x68100142 /proc/kcore:unlock_page 39095 39095 0xffffffff812a64a2 0xffff88fea995dcc8 6 0x68100142 /proc/kcore:half_md4_transform 39095 39095 0x7f0cf877c7e9 0x25dfb94 6 0x68100142 /lib64/libc-2.19.so:__readdir64 39095 39095 0x7f0cf87575a3 0x7f0cf9163731 6 0x68100142 /lib64/libc-2.19.so:__strcoll_l 39095 39095 0xffffffff8116910e 0xffffea01c1bfbd50 23 0x68100242 /proc/kcore:page_remove_rmap As shown above, the -f option really works now. Signed-off-by: Yunlong Song <yunlong.song@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1427982439-27388-7-git-send-email-yunlong.song@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf lock: Support using -f to override perf.data file ownershipYunlong Song2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable perf lock to use perf.data when it is not owned by current user or root. Example: # perf lock record ls # chown Yunlong.Song:Yunlong.Song perf.data # ls -al perf.data -rw------- 1 Yunlong.Song Yunlong.Song 4880686 Apr 2 14:14 perf.data # id uid=0(root) gid=0(root) groups=0(root),64(pkcs11) Before this patch: # perf lock report File perf.data not owned by current user or root (use -f to override) Initializing perf session failed # perf lock report -f Error: unknown switch `f' usage: perf lock report [<options>] -k, --key <acquired> key for sorting (acquired / contended / avg_wait / wait_total / wait_max / wait_min) As shown above, the -f option does not work at all. After this patch: # perf lock report File perf.data not owned by current user or root (use -f to override) Initializing perf session failed # perf lock report -f Name acquired contended avg wait (ns) total wait (ns) ... &ldata->output_l... 128 0 0 0 ... &ctx->lock 114 0 0 0 ... &p->pi_lock 112 0 0 0 ... &(&pool->lock)->... 112 0 0 0 ... &(&dentry->d_loc... 70 0 0 0 ... &(&newf->file_lo... 62 0 0 0 ... &(&fs->lock)->rl... 43 0 0 0 ... ... As shown above, the -f option really works now. Signed-off-by: Yunlong Song <yunlong.song@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1427982439-27388-6-git-send-email-yunlong.song@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf kvm: Support using -f to override perf.data.guest file ownershipYunlong Song2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable perf kvm to use perf.data.guest when it is not owned by current user or root. Example: # perf kvm stat record ls # chown Yunlong.Song:Yunlong.Song perf.data.guest # ls -al perf.data.guest -rw------- 1 Yunlong.Song Yunlong.Song 4128937 Apr 2 11:05 perf.data.guest # id uid=0(root) gid=0(root) groups=0(root),64(pkcs11) Before this patch: # perf kvm stat report File perf.data.guest not owned by current user or root (use -f to override) Initializing perf session failed # perf kvm stat report -f Error: unknown switch `f' usage: perf kvm stat report [<options>] --event <report event> event for reporting: vmexit, mmio (x86 only), ioport (x86 only) --vcpu <n> vcpu id to report -k, --key <sort-key> key for sorting: sample(sort by samples number) time (sort by avg time) -p, --pid <pid> analyze events only for given process id(s) As shown above, the -f option does not work at all. After this patch: # perf kvm stat report File perf.data.guest not owned by current user or root (use -f to override) Initializing perf session failed # perf kvm stat report -f Analyze events for all VMs, all VCPUs: VM-EXIT Samples Samples% Time% Min Time Max Time Avg time Total Samples:0, Total events handled time:0.00us. As shown above, the -f option really works now. Since we have not launched any KVM related process, the result shows 0 sample here. Signed-off-by: Yunlong Song <yunlong.song@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1427982439-27388-5-git-send-email-yunlong.song@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf kmem: Support using -f to override perf.data file ownershipYunlong Song2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable perf kmem to use perf.data when it is not owned by current user or root. Example: # perf kmem record ls # chown Yunlong.Song:Yunlong.Song perf.data # ls -al perf.data -rw------- 1 Yunlong.Song Yunlong.Song 5315665 Apr 2 10:54 perf.data # id uid=0(root) gid=0(root) groups=0(root),64(pkcs11) Before this patch: # perf kmem stat File perf.data not owned by current user or root (use -f to override) # perf kmem stat -f Error: unknown switch `f' usage: perf kmem [<options>] {record|stat} -i, --input <file> input file name -v, --verbose be more verbose (show symbol address, etc) --caller show per-callsite statistics --alloc show per-allocation statistics -s, --sort <key[,key2...]> sort by keys: ptr, call_site, bytes, hit, pingpong, frag -l, --line <num> show n lines --raw-ip show raw ip instead of symbol As shown above, the -f option does not work at all. After this patch: # perf kmem stat File perf.data not owned by current user or root (use -f to override) # perf kmem stat -f SUMMARY ======= Total bytes requested: 437599 Total bytes allocated: 615472 Total bytes wasted on internal fragmentation: 177873 Internal fragmentation: 28.900259% Cross CPU allocations: 6/1192 As shown above, the -f option really works now. Signed-off-by: Yunlong Song <yunlong.song@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1427982439-27388-4-git-send-email-yunlong.song@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf inject: Support using -f to override perf.data file ownershipYunlong Song2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable perf inject to use perf.data when it is not owned by current user or root. Example: # perf record ls # chown Yunlong.Song:Yunlong.Song perf.data # ls -al perf.data -rw------- 1 Yunlong.Song Yunlong.Song 28260 Apr 2 10:37 perf.data # id uid=0(root) gid=0(root) groups=0(root),64(pkcs11) Before this patch: # perf inject -v -b -i perf.data -o perf.data.new File perf.data not owned by current user or root (use -f to override) # perf inject -v -b -i perf.data -o perf.data.new -f Error: unknown switch `f' usage: perf inject [<options>] -b, --build-ids Inject build-ids into the output stream -i, --input <file> input file name -o, --output <file> output file name -s, --sched-stat Merge sched-stat and sched-switch for getting events where and how long tasks slept -v, --verbose be more verbose (show build ids, etc) --kallsyms <file> kallsyms pathname As shown above, the -f option does not work at all. After this patch: # perf inject -v -b -i perf.data -o perf.data.new File perf.data not owned by current user or root (use -f to override) # perf inject -v -b -i perf.data -o perf.data.new -f build id event received for [kernel.kallsyms]: f6dcb66d8b98f1c0d9eb87bf043444b69f91d30c symsrc__init: cannot get elf header. Looking at the vmlinux_path (7 entries long) Using /proc/kcore for kernel object code Using /proc/kallsyms for symbols As shown above, the -f option really works now. Signed-off-by: Yunlong Song <yunlong.song@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1427982439-27388-3-git-send-email-yunlong.song@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf evlist: Support using -f to override perf.data file ownershipYunlong Song2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable perf evlist to use perf.data when it is not owned by current user or root. Example: # perf record ls # chown Yunlong.Song:Yunlong.Song perf.data # ls -al perf.data -rw------- 1 Yunlong.Song Yunlong.Song 28260 Apr 2 10:18 perf.data # id uid=0(root) gid=0(root) groups=0(root),64(pkcs11) Before this patch: # perf evlist File perf.data not owned by current user or root (use -f to override) # perf evlist -f Error: unknown switch `f' usage: perf evlist [<options>] -i, --input <file> Input file name -F, --freq Show the sample frequency -v, --verbose Show all event attr details -g, --group Show event group information As shown above, the -f option does not work at all. After this patch: # perf evlist File perf.data not owned by current user or root (use -f to override) # perf evlist -f cycles As shown above, the -f option really works now. Signed-off-by: Yunlong Song <yunlong.song@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1427982439-27388-2-git-send-email-yunlong.song@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf probe: Fix to track down unnamed union/structure membersMasami Hiramatsu2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix 'perf probe' to track down unnamed union/structure members. perf probe did not track down the tree of unnamed union/structure members, since it just failed to find given "name" in a parent structure/union. To solve this issue, I've introduced 2 changes. - Fix die_find_member() to track down the type-DIE if it is unnamed, and if it contains the specified member, returns the unnamed member. (note that we don't return found member, since unnamed member has the offset in the parent structure) - Fix convert_variable_fields() to track down the unnamed union/ structure (one-by-one). With this patch, perf probe can access unnamed fields: ----- #./perf probe -nfx ./perf lock__delete ops 'locked_ops=ops->locked.ops' Added new event: probe_perf:lock__delete (on lock__delete in /home/mhiramat/ksrc/linux-3/tools/perf/perf with ops locked_ops=ops->locked.ops) You can now use it in all perf tools, such as: perf record -e probe_perf:lock__delete -aR sleep 1 ----- Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org> Report-Link: https://lkml.org/lkml/2015/3/5/431 Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20150402073312.14482.37942.stgit@localhost.localdomain Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf db-export: No need to have ->thread twice in struct export_sampleArnaldo Carvalho de Melo2015-04-02
| | | | | | | | | | | | | | | | | As it comes from address_location->thread, that is already stored as export_sample->al, where the thread can be obtained. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/20150402141542.GA9630@kernel.org Link: http://lkml.kernel.org/n/tip-bzotbl4epoztw0jd6sm2stpf@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf db-export: No need to pass thread twice to db_export__sampleArnaldo Carvalho de Melo2015-04-02
| | | | | | | | | | | | | | | | As it is available via another parameter, address_location->thread. Acked-by: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: lkml.kernel.org/r/551D08F8.3040706@intel.com Link: http://lkml.kernel.org/n/tip-6dbn0tcm9hyv92g7h3zj2dbt@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf scripting: No need to pass thread twice to the scripting callbacksArnaldo Carvalho de Melo2015-04-02
| | | | | | | | | | | | | | | | It is already in the addr_location, so remove the redundant 'thread' parameter from the callback signatures. Acked-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1427906210-10519-3-git-send-email-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf script: No need to lookup thread twiceArnaldo Carvalho de Melo2015-04-02
| | | | | | | | | | | | | | | | We get the thread when we call perf_event__preprocess_sample(), no need to do it before that. Acked-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1427906210-10519-2-git-send-email-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* bpf: Fix the build on BPF_SYSCALL=y && !CONFIG_TRACING kernels, make it more ↵Ingo Molnar2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | configurable So bpf_tracing.o depends on CONFIG_BPF_SYSCALL - but that's not its only dependency, it also depends on the tracing infrastructure and on kprobes, without which it will fail to build with: In file included from kernel/trace/bpf_trace.c:14:0: kernel/trace/trace.h: In function ‘trace_test_and_set_recursion’: kernel/trace/trace.h:491:28: error: ‘struct task_struct’ has no member named ‘trace_recursion’ unsigned int val = current->trace_recursion; [...] It took quite some time to trigger this build failure, because right now BPF_SYSCALL is very obscure, depends on CONFIG_EXPERT. So also make BPF_SYSCALL more configurable, not just under CONFIG_EXPERT. If BPF_SYSCALL, tracing and kprobes are enabled then enable the bpf_tracing gateway as well. We might want to make this an interactive option later on, although I'd not complicate it unnecessarily: enabling BPF_SYSCALL is enough of an indicator that the user wants BPF support. Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* samples/bpf: Add kmem_alloc()/free() tracker toolAlexei Starovoitov2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One BPF program attaches to kmem_cache_alloc_node() and remembers all allocated objects in the map. Another program attaches to kmem_cache_free() and deletes corresponding object from the map. User space walks the map every second and prints any objects which are older than 1 second. Usage: $ sudo tracex4 Then start few long living processes. The 'tracex4' will print something like this: obj 0xffff880465928000 is 13sec old was allocated at ip ffffffff8105dc32 obj 0xffff88043181c280 is 13sec old was allocated at ip ffffffff8105dc32 obj 0xffff880465848000 is 8sec old was allocated at ip ffffffff8105dc32 obj 0xffff8804338bc280 is 15sec old was allocated at ip ffffffff8105dc32 $ addr2line -fispe vmlinux ffffffff8105dc32 do_fork at fork.c:1665 As soon as processes exit the memory is reclaimed and 'tracex4' prints nothing. Similar experiment can be done with the __kmalloc()/kfree() pair. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-10-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* samples/bpf: Add IO latency analysis (iosnoop/heatmap) toolAlexei Starovoitov2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BPF C program attaches to blk_mq_start_request()/blk_update_request() kprobe events to calculate IO latency. For every completed block IO event it computes the time delta in nsec and records in a histogram map: map[log10(delta)*10]++ User space reads this histogram map every 2 seconds and prints it as a 'heatmap' using gray shades of text terminal. Black spaces have many events and white spaces have very few events. Left most space is the smallest latency, right most space is the largest latency in the range. Usage: $ sudo ./tracex3 and do 'sudo dd if=/dev/sda of=/dev/null' in other terminal. Observe IO latencies and how different activity (like 'make kernel') affects it. Similar experiments can be done for network transmit latencies, syscalls, etc. '-t' flag prints the heatmap using normal ascii characters: $ sudo ./tracex3 -t heatmap of IO latency # - many events with this latency - few events |1us |10us |100us |1ms |10ms |100ms |1s |10s *ooo. *O.#. # 221 . *# . # 125 .. .o#*.. # 55 . . . . .#O # 37 .# # 175 .#*. # 37 # # 199 . . *#*. # 55 *#..* # 42 # # 266 ...***Oo#*OO**o#* . # 629 # # 271 . .#o* o.*o* # 221 . . o* *#O.. # 50 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-9-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* samples/bpf: Add counting example for kfree_skb() function calls and the ↵Alexei Starovoitov2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | write() syscall this example has two probes in one C file that attach to different kprove events and use two different maps. 1st probe is x64 specific equivalent of dropmon. It attaches to kfree_skb, retrevies 'ip' address of kfree_skb() caller and counts number of packet drops at that 'ip' address. User space prints 'location - count' map every second. 2nd probe attaches to kprobe:sys_write and computes a histogram of different write sizes Usage: $ sudo tracex2 location 0xffffffff81695995 count 1 location 0xffffffff816d0da9 count 2 location 0xffffffff81695995 count 2 location 0xffffffff816d0da9 count 2 location 0xffffffff81695995 count 3 location 0xffffffff816d0da9 count 2 557145+0 records in 557145+0 records out 285258240 bytes (285 MB) copied, 1.02379 s, 279 MB/s syscall write() stats byte_size : count distribution 1 -> 1 : 3 | | 2 -> 3 : 0 | | 4 -> 7 : 0 | | 8 -> 15 : 0 | | 16 -> 31 : 2 | | 32 -> 63 : 3 | | 64 -> 127 : 1 | | 128 -> 255 : 1 | | 256 -> 511 : 0 | | 512 -> 1023 : 1118968 |************************************* | Ctrl-C at any time. Kernel will auto cleanup maps and programs $ addr2line -ape ./bld_x64/vmlinux 0xffffffff81695995 0xffffffff816d0da9 0xffffffff81695995: ./bld_x64/../net/ipv4/icmp.c:1038 0xffffffff816d0da9: ./bld_x64/../net/unix/af_unix.c:1231 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-8-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* samples/bpf: Add simple non-portable kprobe filter exampleAlexei Starovoitov2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tracex1_kern.c - C program compiled into BPF. It attaches to kprobe:netif_receive_skb() When skb->dev->name == "lo", it prints sample debug message into trace_pipe via bpf_trace_printk() helper function. tracex1_user.c - corresponding user space component that: - loads BPF program via bpf() syscall - opens kprobes:netif_receive_skb event via perf_event_open() syscall - attaches the program to event via ioctl(event_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); - prints from trace_pipe Note, this BPF program is non-portable. It must be recompiled with current kernel headers. kprobe is not a stable ABI and BPF+kprobe scripts may no longer be meaningful when kernel internals change. No matter in what way the kernel changes, neither the kprobe, nor the BPF program can ever crash or corrupt the kernel, assuming the kprobes, perf and BPF subsystem has no bugs. The verifier will detect that the program is using bpf_trace_printk() and the kernel will print 'this is a DEBUG kernel' warning banner, which means that bpf_trace_printk() should be used for debugging of the BPF program only. Usage: $ sudo tracex1 ping-19826 [000] d.s2 63103.382648: : skb ffff880466b1ca00 len 84 ping-19826 [000] d.s2 63103.382684: : skb ffff880466b1d300 len 84 ping-19826 [000] d.s2 63104.382533: : skb ffff880466b1ca00 len 84 ping-19826 [000] d.s2 63104.382594: : skb ffff880466b1d300 len 84 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-7-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* tracing: Allow BPF programs to call bpf_trace_printk()Alexei Starovoitov2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | Debugging of BPF programs needs some form of printk from the program, so let programs call limited trace_printk() with %d %u %x %p modifiers only. Similar to kernel modules, during program load verifier checks whether program is calling bpf_trace_printk() and if so, kernel allocates trace_printk buffers and emits big 'this is debug only' banner. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1427312966-8434-6-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* tracing: Allow BPF programs to call bpf_ktime_get_ns()Alexei Starovoitov2015-04-02
| | | | | | | | | | | | | | | | | | | | | bpf_ktime_get_ns() is used by programs to compute time delta between events or as a timestamp Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1427312966-8434-5-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* tracing, perf: Implement BPF programs attached to kprobesAlexei Starovoitov2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BPF programs, attached to kprobes, provide a safe way to execute user-defined BPF byte-code programs without being able to crash or hang the kernel in any way. The BPF engine makes sure that such programs have a finite execution time and that they cannot break out of their sandbox. The user interface is to attach to a kprobe via the perf syscall: struct perf_event_attr attr = { .type = PERF_TYPE_TRACEPOINT, .config = event_id, ... }; event_fd = perf_event_open(&attr,...); ioctl(event_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); 'prog_fd' is a file descriptor associated with BPF program previously loaded. 'event_id' is an ID of the kprobe created. Closing 'event_fd': close(event_fd); ... automatically detaches BPF program from it. BPF programs can call in-kernel helper functions to: - lookup/update/delete elements in maps - probe_read - wraper of probe_kernel_read() used to access any kernel data structures BPF programs receive 'struct pt_regs *' as an input ('struct pt_regs' is architecture dependent) and return 0 to ignore the event and 1 to store kprobe event into the ring buffer. Note, kprobes are a fundamentally _not_ a stable kernel ABI, so BPF programs attached to kprobes must be recompiled for every kernel version and user must supply correct LINUX_VERSION_CODE in attr.kern_version during bpf_prog_load() call. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1427312966-8434-4-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* tracing: Add kprobe flagAlexei Starovoitov2015-04-02
| | | | | | | | | | | | | | | | | | | | | | add TRACE_EVENT_FL_KPROBE flag to differentiate kprobe type of tracepoints, since bpf programs can only be attached to kprobe type of PERF_TYPE_TRACEPOINT perf events. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1427312966-8434-3-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* bpf: Make internal bpf API independent of CONFIG_BPF_SYSCALL #ifdefsDaniel Borkmann2015-04-02
| | | | | | | | | | | | | | | | | | | | | | | | | | Socket filter code and other subsystems with upcoming eBPF support should not need to deal with the fact that we have CONFIG_BPF_SYSCALL defined or not. Having the bpf syscall as a config option is a nice thing and I'd expect it to stay that way for expert users (I presume one day the default setting of it might change, though), but code making use of it should not care if it's actually enabled or not. Instead, hide this via header files and let the rest deal with it. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1427312966-8434-2-git-send-email-ast@plumgrid.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'perf/timer' into perf/coreIngo Molnar2015-04-02
|\ | | | | | | | | | | This WIP branch is now ready to be merged. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * perf: Add per event clockid supportPeter Zijlstra2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While thinking on the whole clock discussion it occurred to me we have two distinct uses of time: 1) the tracking of event/ctx/cgroup enabled/running/stopped times which includes the self-monitoring support in struct perf_event_mmap_page. 2) the actual timestamps visible in the data records. And we've been conflating them. The first is all about tracking time deltas, nobody should really care in what time base that happens, its all relative information, as long as its internally consistent it works. The second however is what people are worried about when having to merge their data with external sources. And here we have the discussion on MONOTONIC vs MONOTONIC_RAW etc.. Where MONOTONIC is good for correlating between machines (static offset), MONOTNIC_RAW is required for correlating against a fixed rate hardware clock. This means configurability; now 1) makes that hard because it needs to be internally consistent across groups of unrelated events; which is why we had to have a global perf_clock(). However, for 2) it doesn't really matter, perf itself doesn't care what it writes into the buffer. The below patch makes the distinction between these two cases by adding perf_event_clock() which is used for the second case. It further makes this configurable on a per-event basis, but adds a few sanity checks such that we cannot combine events with different clocks in confusing ways. And since we then have per-event configurability we might as well retain the 'legacy' behaviour as a default. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * Merge branch 'perf/core' into perf/timer, before applying new changesIngo Molnar2015-03-27
| |\ | | | | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * \ Merge branch 'timers/core' into perf/timer, to apply dependent patchIngo Molnar2015-03-27
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | An upcoming patch will depend on tai_ns() and NMI-safe ktime_get_raw_fast(), so merge timers/core here in a separate topic branch until it's all cooked and timers/core is merged upstream. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | time: Add ktime_get_tai_ns()Peter Zijlstra2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Because it was the only clock for which we didn't have a _ns() accessor yet. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | time: Introduce tk_fast_rawPeter Zijlstra2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the NMI safe CLOCK_MONOTONIC_RAW accessor.. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150319093400.562746929@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | time: Parametrize all tk_fast_mono usersPeter Zijlstra2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation for more tk_fast instances, remove all hard-coded tk_fast_mono references. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150319093400.484279927@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | time: Add timerkeeper::tkr_rawPeter Zijlstra2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce tkr_raw and make use of it. base_raw -> tkr_raw.base clock->{mult,shift} -> tkr_raw.{mult.shift} Kill timekeeping_get_ns_raw() in favour of timekeeping_get_ns(&tkr_raw), this removes all mono_raw special casing. Duplicate the updates to tkr_mono.cycle_last into tkr_raw.cycle_last, both need the same value. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150319093400.422589590@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | time: Rename timekeeper::tkr to timekeeper::tkr_monoPeter Zijlstra2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation of adding another tkr field, rename this one to tkr_mono. Also rename tk_read_base::base_mono to tk_read_base::base, since the structure is not specific to CLOCK_MONOTONIC and the mono name got added to the tk_read_base instance. Lots of trivial churn. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150319093400.344679419@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | timers, sched/clock: Clean up the code a bitIngo Molnar2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Trivial cleanups, to improve the readability of the generic sched_clock() code: - Improve and standardize comments - Standardize the coding style - Use vertical spacing where appropriate - etc. No code changed: md5: 19a053b31e0c54feaeff1492012b019a sched_clock.o.before.asm 19a053b31e0c54feaeff1492012b019a sched_clock.o.after.asm Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | timers, sched/clock: Avoid deadlock during read from NMIDaniel Thompson2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently it is possible for an NMI (or FIQ on ARM) to come in and read sched_clock() whilst update_sched_clock() has locked the seqcount for writing. This results in the NMI handler locking up when it calls raw_read_seqcount_begin(). This patch fixes the NMI safety issues by providing banked clock data. This is a similar approach to the one used in Thomas Gleixner's 4396e058c52e("timekeeping: Provide fast and NMI safe access to CLOCK_MONOTONIC"). Suggested-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1427397806-20889-6-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | timers, sched/clock: Remove redundant notrace from update functionDaniel Thompson2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently update_sched_clock() is marked as notrace but this function is not called by ftrace. This is trivially fixed by removing the mark up. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1427397806-20889-5-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | timers, sched/clock: Remove suspend from clock_read_data()Daniel Thompson2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently cd.read_data.suspended is read by the hotpath function sched_clock(). This variable need not be accessed on the hotpath. In fact, once it is removed, we can remove the conditional branches from sched_clock() and install a dummy read_sched_clock function to suspend the clock. The new master copy of the function pointer (actual_read_sched_clock) is introduced and is used for all reads of the clock hardware except those within sched_clock itself. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1427397806-20889-4-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | timers, sched/clock: Optimize cache line usageDaniel Thompson2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently sched_clock(), a very hot code path, is not optimized to minimise its cache profile. In particular: 1. cd is not ____cacheline_aligned, 2. struct clock_data does not distinguish between hotpath and coldpath data, reducing locality of reference in the hotpath, 3. Some hotpath data is missing from struct clock_data and is marked __read_mostly (which more or less guarantees it will not share a cache line with cd). This patch corrects these problems by extracting all hotpath data into a separate structure and using ____cacheline_aligned to ensure the hotpath uses a single (64 byte) cache line. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1427397806-20889-3-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | timers, sched/clock: Match scope of read and write seqcountsDaniel Thompson2015-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the scope of the raw_write_seqcount_begin/end() in sched_clock_register() far exceeds the scope of the read section in sched_clock(). This gives the impression of safety during cursory review but achieves little. Note that this is likely to be a latent issue at present because sched_clock_register() is typically called before we enable interrupts, however the issue does risk bugs being needlessly introduced as the code evolves. This patch fixes the problem by increasing the scope of the read locking performed by sched_clock() to cover all data modified by sched_clock_register. We also improve clarity by moving writes to struct clock_data that do not impact sched_clock() outside of the critical section. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> [ Reworked it slightly to apply to tip/timers/core] Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1427397806-20889-2-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | Merge branch 'timers/urgent' into timers/core, to pick up fixes before ↵Ingo Molnar2015-03-17
| | |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | applying new changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | clocksource: Rename __clocksource_updatefreq_*() to ↵John Stultz2015-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __clocksource_update_freq_*() Ingo requested this function be renamed to improve readability, so I've renamed __clocksource_updatefreq_scale() as well as the __clocksource_updatefreq_hz/khz() functions to avoid squishedtogethernames. This touches some of the sh clocksources, which I've not tested. The arch/arm/plat-omap change is just a comment change for consistency. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-13-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | clocksource: Add some debug info about clocksources being registeredJohn Stultz2015-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Print the mask, max_cycles, and max_idle_ns values for clocksources being registered. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-12-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | clocksource, sparc32: Convert to using clocksource_register_hz()John Stultz2015-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While cleaning up some clocksource code, I noticed the time_32 implementation uses the clocksource_hz2mult() helper, but doesn't use the clocksource_register_hz() method. I don't believe the Sparc clocksource is a default clocksource, so we shouldn't need to self-define the mult/shift pair. So convert the time_32.c implementation to use clocksource_register_hz(). Untested. Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: David S. Miller <davem@davemloft.net> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-11-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | clocksource: Mostly kill clocksource_register()John Stultz2015-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A long running project has been to clean up remaining uses of clocksource_register(), replacing it with the simpler clocksource_register_khz/hz() functions. However, there are a few cases where we need to self-define our mult/shift values, so switch the function to a more obviously internal __clocksource_register() name, and consolidate much of the internal logic so we don't have duplication. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-10-git-send-email-john.stultz@linaro.org [ Minor cleanups. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | clocksource: Improve clocksource watchdog reportingJohn Stultz2015-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The clocksource watchdog reporting has been less helpful then desired, as it just printed the delta between the two clocksources. This prevents any useful analysis of why the skew occurred. Thus this patch tries to improve the output when we mark a clocksource as unstable, printing out the cycle last and now values for both the current clocksource and the watchdog clocksource. This will allow us to see if the result was due to a false positive caused by a problematic watchdog. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-9-git-send-email-john.stultz@linaro.org [ Minor cleanups of kernel messages. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | timekeeping: Add warnings when overflows or underflows are observedJohn Stultz2015-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It was suggested that the underflow/overflow protection should probably throw some sort of warning out, rather than just silently fixing the issue. So this patch adds some warnings here. The flag variables used are not protected by locks, but since we can't print from the reading functions, just being able to say we saw an issue in the update interval is useful enough, and can be slightly racy without real consequence. The big complication is that we're only under a read seqlock, so the data could shift under us during our calculation to see if there was a problem. This patch avoids this issue by nesting another seqlock which allows us to snapshot the just required values atomically. So we shouldn't see false positives. I also added some basic rate-limiting here, since on one build machine w/ skewed TSCs it was fairly noisy at bootup. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-8-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | timekeeping: Try to catch clocksource delta underflowsJohn Stultz2015-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the case where there is a broken clocksource where there are multiple actual clocks that aren't perfectly aligned, we may see small "negative" deltas when we subtract 'now' from 'cycle_last'. The values are actually negative with respect to the clocksource mask value, not necessarily negative if cast to a s64, but we can check by checking the delta to see if it is a small (relative to the mask) negative value (again negative relative to the mask). If so, we assume we jumped backwards somehow and instead use zero for our delta. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-7-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | timekeeping: Add checks to cap clocksource reads to the 'max_cycles' valueJohn Stultz2015-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When calculating the current delta since the last tick, we currently have no hard protections to prevent a multiplication overflow from occuring. This patch introduces infrastructure to allow a cap that limits the clocksource read delta value to the 'max_cycles' value, which is where an overflow would occur. Since this is in the hotpath, it adds the extra checking under CONFIG_DEBUG_TIMEKEEPING=y. There was some concern that capping time like this could cause problems as we may stop expiring timers, which could go circular if the timer that triggers time accumulation were mis-scheduled too far in the future, which would cause time to stop. However, since the mult overflow would result in a smaller time value, we would effectively have the same problem there. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-6-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | timekeeping: Add debugging checks to warn if we see delaysJohn Stultz2015-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recently there's been requests for better sanity checking in the time code, so that it's more clear when something is going wrong, since timekeeping issues could manifest in a large number of strange ways in various subsystems. Thus, this patch adds some extra infrastructure to add a check to update_wall_time() to print two new warnings: 1) if we see the call delayed beyond the 'max_cycles' overflow point, 2) or if we see the call delayed beyond the clocksource's 'max_idle_ns' value, which is currently 50% of the overflow point. This extra infrastructure is conditional on a new CONFIG_DEBUG_TIMEKEEPING option, also added in this patch - default off. Tested this a bit by halting qemu for specified lengths of time to trigger the warnings. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-5-git-send-email-john.stultz@linaro.org [ Improved the changelog and the messages a bit. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | clocksource: Add 'max_cycles' to 'struct clocksource'John Stultz2015-03-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to facilitate clocksource validation, add a 'max_cycles' field to the clocksource structure which will hold the maximum cycle value that can safely be multiplied without potentially causing an overflow. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-4-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | clocksource: Simplify the logic around clocksource wrapping safety marginsJohn Stultz2015-03-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The clocksource logic has a number of places where we try to include a safety margin. Most of these are 12% safety margins, but they are inconsistently applied and sometimes are applied on top of each other. Additionally, in the previous patch, we corrected an issue where we unintentionally in effect created a 50% safety margin, which these 12.5% margins where then added to. So to simplify the logic here, this patch removes the various 12.5% margins, and consolidates adding the margin in one place: clocks_calc_max_nsecs(). Additionally, Linus prefers a 50% safety margin, as it allows bad clock values to be more easily caught. This should really have no net effect, due to the corrected issue earlier which caused greater then 50% margins to be used w/o issue. Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: Stephen Boyd <sboyd@codeaurora.org> (for the sched_clock.c bit) Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-3-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | clocksource: Simplify the clocks_calc_max_nsecs() logicJohn Stultz2015-03-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous clocks_calc_max_nsecs() code had some unecessarily complex bit logic to find the max interval that could cause multiplication overflows. Since this is not in the hot path, just do the divide to make it easier to read. The previous implementation also had a subtle issue that it avoided overflows with signed 64-bit values, where as the intervals are always unsigned. This resulted in overly conservative intervals, which other safety margins were then added to, reducing the intended interval length. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-2-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | Merge tag 'v4.0-rc2' into timers/core, to refresh the tree before pulling ↵Ingo Molnar2015-03-04
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