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* libperf: Use sys/types.h to get ssize_t, not unistd.hArnaldo Carvalho de Melo2019-09-25
| | | | | | | | | | | | | | The sys/types.h header looks more sensible, from its name we can gather it should be there because of some needed typedef, and it is much smaller than unistd.h, so use it and fix up the fallout in places where it was being used for something else entirely but being obtained by sheer luck, indirectly. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-49bn251httu22ymwgipeavmy@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Move 'page_size' global variable to libperfJiri Olsa2019-09-25
| | | | | | | | | | | | | | | | | | | | | We need the 'page_size' variable in libperf, so move it there. Add a libperf_init() as a global libperf init function to obtain this value via sysconf() at tool start. Committer notes: Add internal/lib.h to tools/perf/ files using 'page_size', sometimes replacing util.h with it if that was the only reason for having util.h included. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-33-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Add 'flush' to 'struct perf_mmap'Jiri Olsa2019-09-25
| | | | | | | | | | | | Move 'flush' from tools/perf's mmap to libperf's perf_mmap struct. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-19-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Add 'event_copy' to 'struct perf_mmap'Jiri Olsa2019-09-25
| | | | | | | | | | | | | | | | Move 'event_copy' from tools/perf's mmap to libperf's perf_mmap struct. Committer notes: Add linux/compiler.h as we need it for '__aligned'. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-18-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Add 'overwrite' to 'struct perf_mmap'Jiri Olsa2019-09-25
| | | | | | | | | | | | | | | | Move 'overwrite' from tools/perf's mmap to libperf's perf_mmap struct. Committer notes: Add stdbool.h as we start using 'bool'. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-17-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Add prev/start/end to struct perf_mmapJiri Olsa2019-09-25
| | | | | | | | | | | | | | | | Move prev/start/end from tools/perf's mmap to libperf's perf_mmap struct. Committer notes: Add linux/types.h as we use u64. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-16-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Add 'refcnt' to struct perf_mmapJiri Olsa2019-09-25
| | | | | | | | | | | | | | | | Move 'refcnt' from tools/perf's mmap to libperf's perf_mmap struct. Committer notes: Add the refcount.h include directive here, now it is needed. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-15-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Add 'cpu' to struct perf_mmapJiri Olsa2019-09-25
| | | | | | | | | | | | Move 'cpu' from tools/perf's mmap to libperf's perf_mmap struct. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-14-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Add 'fd' to struct perf_mmapJiri Olsa2019-09-25
| | | | | | | | | | | | Move 'fd' from tools/perf's mmap to libperf's perf_mmap struct. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-13-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Add 'mask' to struct perf_mmapJiri Olsa2019-09-25
| | | | | | | | | | | | Move 'mask' from tools/perf's mmap to libperf's perf_mmap struct. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-12-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* libperf: Add perf_mmap structJiri Olsa2019-09-25
| | | | | | | | | | | | | | | | | | | | | | | | Add the perf_mmap struct to libperf. The definition is added into: include/internal/mmap.h which is not to be included by users, but shared within perf and libperf. Committer notes: Remove unnecessary includes from tools/perf/lib/include/internal/mmap.h, those will be readded as they become necessary, later in the series. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-11-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf tools: Rename 'struct perf_mmap' to 'struct mmap'Jiri Olsa2019-09-25
| | | | | | | | | | | | | Rename 'struct perf_evlist' to 'struct evlist', so we don't have a name clash when we add 'struct perf_mmap' to libperf. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lore.kernel.org/lkml/20190913132355.21634-4-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf auxtrace: Uninline functions that touch perf_sessionArnaldo Carvalho de Melo2019-08-31
| | | | | | | | | | | | So that we don't carry the session.h include directive in auxtrace.h, which in turn opens a can of worms of files that were getting all sorts of things via that include, fix them all. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-d2d83aovpgri2z75wlitquni@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf tools: Remove needless perf.h include directive from headersArnaldo Carvalho de Melo2019-08-29
| | | | | | | | | | | Its not needed there, add it to the places that need it and were getting it via those headers. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-5yulx1u16vyd0zmrbg1tjhju@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf tools: Use perf_cpu_map__nr instead of cpu_map__nrJiri Olsa2019-08-22
| | | | | | | | | | | | | | | Switch the rest of the perf code to use libperf's perf_cpu_map__nr(), which is the same as current cpu_map__nr() and remove the cpu_map__nr() function. Link: http://lkml.kernel.org/n/tip-6e0guy75clis7nm0xpuz9fga@git.kernel.org Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20190822111141.25823-3-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf evlist: Rename struct perf_evlist to struct evlistJiri Olsa2019-07-29
| | | | | | | | | | | | | | | | | | | | Rename struct perf_evlist to struct evlist, so we don't have a name clash when we add struct perf_evlist in libperf. Committer notes: Added fixes to build on arm64, from Jiri and from me (tools/perf/util/cs-etm.c) Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20190721112506.12306-6-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf cpu_map: Rename struct cpu_map to struct perf_cpu_mapJiri Olsa2019-07-29
| | | | | | | | | | | | | | | | | | | Rename struct cpu_map to struct perf_cpu_map, so it could be part of libperf. Committer notes: Added fixes for arm64, provided by Jiri. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20190721112506.12306-3-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* tools lib: Adopt zalloc()/zfree() from tools/perfArnaldo Carvalho de Melo2019-07-09
| | | | | | | | | | Eroding a bit more the tools/perf/util/util.h hodpodge header. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-natazosyn9rwjka25tvcnyi0@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 251Thomas Gleixner2019-06-05
| | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): released under the gpl v2 and only v2 not any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 12 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141332.526460839@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* perf record: Implement compression for AIO trace streamingAlexey Budankov2019-05-15
| | | | | | | | | | | | | | | | | | | | | | | | | | Compression is implemented using the functions from zstd.c. As the memory to operate on the compression uses mmap->aio.data[] buffers. If Zstd streaming compression API fails for some reason the data to be compressed are just copied into the memory buffers using plain memcpy(). Compressed trace frame consists of an array of PERF_RECORD_COMPRESSED records. Each element of the array is not longer that PERF_SAMPLE_MAX_SIZE and consists of perf_event_header followed by the compressed chunk that is decompressed on the loading stage. perf_mmap__aio_push() is replaced by perf_mmap__push() which is now used in the both serial and AIO streaming cases. perf_mmap__push() is extended with positive return values to signify absence of data ready for processing. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/77db2b2c-5d03-dbb0-aeac-c4dd92129ab9@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Implement dedicated memory buffer for data compressionAlexey Budankov2019-05-15
| | | | | | | | | | | | | | Implemented mmap data buffer that is used as the memory to operate on when compressing data in case of serial trace streaming. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/49b31321-0f70-392b-9a4f-649d3affe090@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf record: Implement --mmap-flush=<number> optionAlexey Budankov2019-04-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement a --mmap-flush option that specifies minimal number of bytes that is extracted from mmaped kernel buffer to store into a trace. The default option value is 1 byte what means every time trace writing thread finds some new data in the mmaped buffer the data is extracted, possibly compressed and written to a trace. $ tools/perf/perf record --mmap-flush 1024 -e cycles -- matrix.gcc $ tools/perf/perf record --aio --mmap-flush 1K -e cycles -- matrix.gcc The option is independent from -z setting, doesn't vary with compression level and can serve two purposes. The first purpose is to increase the compression ratio of a trace data. Larger data chunks are compressed more effectively so the implemented option allows specifying data chunk size to compress. Also at some cases executing more write syscalls with smaller data size can take longer than executing less write syscalls with bigger data size due to syscall overhead so extracting bigger data chunks specified by the option value could additionally decrease runtime overhead. The second purpose is to avoid self monitoring live-lock issue in system wide (-a) profiling mode. Profiling in system wide mode with compression (-a -z) can additionally induce data into the kernel buffers along with the data from monitored processes. If performance data rate and volume from the monitored processes is high then trace streaming and compression activity in the tool is also high. High tool process activity can lead to subtle live-lock effect when compression of single new byte from some of mmaped kernel buffer leads to generation of the next single byte at some mmaped buffer. So perf tool process ends up in endless self monitoring. Implemented synch parameter is the mean to force data move independently from the specified flush threshold value. Despite the provided flush value the tool needs capability to unconditionally drain memory buffers, at least in the end of the collection. Committer testing: Running with the default value, i.e. as soon as there is something to read go on consuming, we first write the synthesized events, small chunks of about 128 bytes: # perf trace -m 2048 --call-graph dwarf -e write -- perf record <SNIP> 101.142 ( 0.004 ms): perf/25821 write(fd: 3</root/perf.data>, buf: 0x210db60, count: 120) = 120 __libc_write (/usr/lib64/libpthread-2.28.so) ion (/home/acme/bin/perf) record__write (inlined) process_synthesized_event (/home/acme/bin/perf) perf_tool__process_synth_event (inlined) perf_event__synthesize_mmap_events (/home/acme/bin/perf) Then we move to reading the mmap buffers consuming the events put there by the kernel perf infrastructure: 107.561 ( 0.005 ms): perf/25821 write(fd: 3</root/perf.data>, buf: 0x7f1befc02000, count: 336) = 336 __libc_write (/usr/lib64/libpthread-2.28.so) ion (/home/acme/bin/perf) record__write (inlined) record__pushfn (/home/acme/bin/perf) perf_mmap__push (/home/acme/bin/perf) record__mmap_read_evlist (inlined) record__mmap_read_all (inlined) __cmd_record (inlined) cmd_record (/home/acme/bin/perf) 12919.953 ( 0.136 ms): perf/25821 write(fd: 3</root/perf.data>, buf: 0x7f1befc83150, count: 184984) = 184984 <SNIP same backtrace as in the 107.561 timestamp> 12920.094 ( 0.155 ms): perf/25821 write(fd: 3</root/perf.data>, buf: 0x7f1befc02150, count: 261816) = 261816 <SNIP same backtrace as in the 107.561 timestamp> 12920.253 ( 0.093 ms): perf/25821 write(fd: 3</root/perf.data>, buf: 0x7f1befb81120, count: 170832) = 170832 <SNIP same backtrace as in the 107.561 timestamp> If we limit it to write only when more than 16MB are available for reading, it throttles that to a quarter of the --mmap-pages set for 'perf record', which by default get to 528384 bytes, found out using 'record -v': mmap flush: 132096 mmap size 528384B With that in place all the writes coming from record__mmap_read_evlist(), i.e. from the mmap buffers setup by the kernel perf infrastructure were at least 132096 bytes long. Trying with a bigger mmap size: perf trace -e write perf record -v -m 2048 --mmap-flush 16M 74982.928 ( 2.471 ms): perf/26500 write(fd: 3</root/perf.data>, buf: 0x7ff94a6cc000, count: 3580888) = 3580888 74985.406 ( 2.353 ms): perf/26500 write(fd: 3</root/perf.data>, buf: 0x7ff949ecb000, count: 3453256) = 3453256 74987.764 ( 2.629 ms): perf/26500 write(fd: 3</root/perf.data>, buf: 0x7ff9496ca000, count: 3859232) = 3859232 74990.399 ( 2.341 ms): perf/26500 write(fd: 3</root/perf.data>, buf: 0x7ff948ec9000, count: 3769032) = 3769032 74992.744 ( 2.064 ms): perf/26500 write(fd: 3</root/perf.data>, buf: 0x7ff9486c8000, count: 3310520) = 3310520 74994.814 ( 2.619 ms): perf/26500 write(fd: 3</root/perf.data>, buf: 0x7ff947ec7000, count: 4194688) = 4194688 74997.439 ( 2.787 ms): perf/26500 write(fd: 3</root/perf.data>, buf: 0x7ff9476c6000, count: 4029760) = 4029760 Was again limited to a quarter of the mmap size: mmap flush: 2098176 mmap size 8392704B A warning about that would be good to have but can be added later, something like: "max flush is a quarter of the mmap size, if wanting to bump the mmap flush further, bump the mmap size as well using -m/--mmap-pages" Also rename the 'sync' parameters to 'synch' to keep tools/perf building with older glibcs: cc1: warnings being treated as errors builtin-record.c: In function 'record__mmap_read_evlist': builtin-record.c:775: warning: declaration of 'sync' shadows a global declaration /usr/include/unistd.h:933: warning: shadowed declaration is here builtin-record.c: In function 'record__mmap_read_all': builtin-record.c:856: warning: declaration of 'sync' shadows a global declaration /usr/include/unistd.h:933: warning: shadowed declaration is here Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/f6600d72-ecfa-2eb7-7e51-f6954547d500@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf record: Apply affinity masks when reading mmap buffersAlexey Budankov2019-02-06
| | | | | | | | | | | | | | | Build node cpu masks for mmap data buffers. Apply node cpu masks to tool thread every time it references data buffers cross node or cross cpu. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/b25e4ebc-078d-2c7b-216c-f0bed108d073@linux.intel.com [ Use cpu-set-sched.h to get the CPU_{EQUAL,OR}() fallbacks for older systems ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf record: Bind the AIO user space buffers to nodesAlexey Budankov2019-02-06
| | | | | | | | | | | | | | | | | Allocate and bind AIO user space buffers to the memory nodes that mmap kernel buffers are bound to. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/5a5adebc-afe0-4806-81cd-180d49ec043f@linux.intel.com [ Do not use 'index' as a variable name, it is a define in older glibcs ] Link: http://lkml.kernel.org/r/20190205151526.GC10613@kernel.org [ Add -lnuma to the python build when -DHAVE_LIBNUMA_SUPPORT is present, fixing 'perf test python' ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf record: Allocate affinity masksAlexey Budankov2019-02-06
| | | | | | | | | | | | | | Allocate affinity option and masks for mmap data buffers and record thread as well as initialize allocated objects. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/526fa2b0-07de-6dbd-a7e9-26ba875593c9@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf record: Fix memory leak on AIO objects deallocationAlexey Budankov2018-12-17
| | | | | | | | | | | | | | | | | | Sending a part which was missed between v12 and v13 of the patch set introducing AIO trace streaming for perf record mode. The part is essential to avoid memory leakage during deallocation of AIO related trace data buffers. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.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/e5d3154e-1583-83bb-9527-28ddbc6dbf9d@linux.intel.com [ No need to test for NULL before calling zfree() ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf record: Extend trace writing to multi AIOAlexey Budankov2018-12-17
| | | | | | | | | | | | | | | | | | | | | | | | Multi AIO trace writing allows caching more kernel data into userspace memory postponing trace writing for the sake of overall profiling data thruput increase. It could be seen as kernel data buffer extension into userspace memory. With an --aio option value different from 0 (default value is 1) the tool has capability to cache more and more data into user space along with delegating spill to AIO. That allows avoiding to suspend at record__aio_sync() between calls of record__mmap_read_evlist() and increases profiling data thruput at the cost of userspace memory. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/050bb053-e7f3-aa83-fde7-f27ff90be7f6@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf record: Enable asynchronous trace writingAlexey Budankov2018-12-17
| | | | | | | | | | | | | | | | | | | | | | | The trace file offset is read once before mmaps iterating loop and written back after all performance data is enqueued for aio writing. The trace file offset is incremented linearly after every successful aio write operation. record__aio_sync() blocks till completion of the started AIO operation and then proceeds. record__aio_mmap_read_sync() implements a barrier for all incomplete aio write requests. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/ce2d45e9-d236-871c-7c8f-1bed2d37e8ac@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Map data buffer for preserving collected dataAlexey Budankov2018-12-17
| | | | | | | | | | | | | | | The map->data buffer is used to preserve map->base profiling data for writing to disk. AIO map->cblock is used to queue corresponding map->data buffer for asynchronous writing. Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> Reviewed-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/5fcda10c-6c63-68df-383a-c6d9e5d1f918@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf tools: Add 'struct perf_mmap' arg to record__write()Jiri Olsa2018-09-19
| | | | | | | | | | | | | | The struct perf_mmap map argument will hold the file pointer to write the data to. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180913125450.21342-5-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Store real cpu number in 'struct perf_mmap'Jiri Olsa2018-08-20
| | | | | | | | | | | | | | | | Store the real cpu number in 'struct perf_mmap', which will be used by python interface that allows user to read a particular memory map for given cpu. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jaroslav Škarvada <jskarvad@redhat.com> Cc: Joe Mario <jmario@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180817114556.28000-2-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Be consistent when checking for an unmaped ring bufferArnaldo Carvalho de Melo2018-03-27
| | | | | | | | | | | | | | | | | | The previous patch is insufficient to cure the reported 'perf trace' segfault, as it only cures the perf_mmap__read_done() case, moving the segfault to perf_mmap__read_init() functio, fix it by doing the same refcount check. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Fixes: 8872481bd048 ("perf mmap: Introduce perf_mmap__read_init()") Link: https://lkml.kernel.org/r/20180326144127.GF18897@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Fix accessing unmapped mmap in perf_mmap__read_done()Kan Liang2018-03-27
| | | | | | | | | | | | | | | | | | There is a segmentation fault when running 'perf trace'. For example: [root@jouet e]# perf trace -e *chdir -o /tmp/bla perf report --ignore-vmlinux -i ../perf.data The perf_mmap__consume() could unmap the mmap. It needs to check the refcnt in perf_mmap__read_done(). Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Fixes: ee023de05f35 ("perf mmap: Introduce perf_mmap__read_done()") Link: http://lkml.kernel.org/r/1522071729-16776-1-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Discard head in overwrite_rb_find_range()Yisheng Xie2018-03-16
| | | | | | | | | | | | | | | | In overwrite mode, start will be set to head in perf_mmap__read_init(). Therefore, there is no need to set the start one more time in overwrite_rb_find_range() and *start can be used as head instead of passing head to overwrite_rb_find_range(). Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.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/1520944274-37001-1-git-send-email-xieyisheng1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Simplify perf_mmap__read_init()Kan Liang2018-03-08
| | | | | | | | | | | | | | | | It isn't necessary to pass the 'start', 'end' and 'overwrite' arguments to perf_mmap__read_init(). The data is stored in the struct perf_mmap. Discard the parameters. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1520350567-80082-8-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Simplify perf_mmap__read_event()Kan Liang2018-03-08
| | | | | | | | | | | | | | It isn't necessary to pass the 'overwrite', 'start' and 'end' argument to perf_mmap__read_event(). Discard them. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1520350567-80082-7-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Simplify perf_mmap__consume()Kan Liang2018-03-08
| | | | | | | | | | | | | | It isn't necessary to pass the 'overwrite' argument to perf_mmap__consume(). Discard it. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1520350567-80082-6-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Use stored 'overwrite' in perf_mmap__consume()Kan Liang2018-03-08
| | | | | | | | | | | | | | | | | The 'overwrite' is set at allocation. It will not be changed. Using it to replace the parameter of perf_mmap__consume(). The parameters will be discarded later. No functional change. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1520350567-80082-5-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Use the stored data in perf_mmap__read_event()Kan Liang2018-03-08
| | | | | | | | | | | | | | | | | Using the 'start', 'end' and 'overwrite' which are stored in struct perf_mmap to replace the parameters of perf_mmap__read_event(). The parameters will be discarded later. No functional change. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1520350567-80082-4-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Use the stored scope data in perf_mmap__push()Kan Liang2018-03-08
| | | | | | | | | | | | | | | | | | Using the 'start' and 'end' which are stored in struct perf_mmap to replace the temporary 'start' and 'end'. The temporary variables will be discarded later. It doesn't need to pass 'overwrite' to perf_mmap__push(). It's stored in struct perf_mmap. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1520350567-80082-3-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Store mmap scope in struct perf_mmap()Kan Liang2018-03-08
| | | | | | | | | | | | | | | | | | | | | There is too much boilerplate in the perf_mmap__read*() interfaces. The 'start' and 'end' variables should be stored in struct perf_mmap at initialization. They will be used later. The old 'startp' and 'endp' pointers are used by perf_mmap__read_event() now. They cannot be removed. So the old 'startp/endp' and new 'md->start/md->end' will exist simultaneously now. The old one will be removed later. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1520350567-80082-2-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Discard legacy interfaces for mmap read forwardKan Liang2018-03-05
| | | | | | | | | | | | | | | Discards legacy interfaces perf_evlist__mmap_read_forward(), perf_evlist__mmap_read() and perf_evlist__mmap_consume(). No tools use them. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1519945751-37786-14-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Discard legacy interface for mmap readKan Liang2018-02-15
| | | | | | | | | | | | | | | | | | Discards perf_mmap__read_backward() and perf_mmap__read_catchup(). No tools use them. There are tools still use perf_mmap__read_forward(). Keep it, but add comments to point to the new interface for future use. Signed-off-by: Kan Liang <kan.liang@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1516310792-208685-11-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Introduce perf_mmap__read_event()Kan Liang2018-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Except for 'perf record', the other perf tools read events one by one from the ring buffer using perf_mmap__read_forward(). But it only supports non-overwrite mode. Introduce perf_mmap__read_event() to support both non-overwrite and overwrite mode. Usage: perf_mmap__read_init() while(event = perf_mmap__read_event()) { //process the event perf_mmap__consume() } perf_mmap__read_done() It cannot use perf_mmap__read_backward(). Because it always reads the stale buffer which is already processed. Furthermore, the forward and backward concepts have been removed. The perf_mmap__read_backward() will be replaced and discarded later. Signed-off-by: Kan Liang <kan.liang@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1516310792-208685-9-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Introduce perf_mmap__read_done()Kan Liang2018-02-15
| | | | | | | | | | | | | | | | | | The direction of overwrite mode is backward. The last perf_mmap__read() will set tail to map->prev. Need to correct the map->prev to head which is the end of next read. It will be used later. Signed-off-by: Kan Liang <kan.liang@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1516310792-208685-8-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Discard 'prev' in perf_mmap__read()Kan Liang2018-02-15
| | | | | | | | | | | | | | | | | The 'start' and 'prev' variables are duplicates in perf_mmap__read(). Use 'map->prev' to replace 'start' in perf_mmap__read_*(). Suggested-by: Wang Nan <wangnan0@huawei.com> Signed-off-by: Kan Liang <kan.liang@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1516310792-208685-7-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Add new return value logic for perf_mmap__read_init()Kan Liang2018-02-15
| | | | | | | | | | | | | | | | Improve the readability by using meaningful enum (-EAGAIN, -EINVAL and 0) to replace the three returning states (0, -1 and 1). Suggested-by: Wang Nan <wangnan0@huawei.com> Signed-off-by: Kan Liang <kan.liang@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1516310792-208685-6-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Introduce perf_mmap__read_init()Kan Liang2018-02-15
| | | | | | | | | | | | | | | | | | | | The new function perf_mmap__read_init() is factored out from perf_mmap__push(). It is to calculate the 'start' and 'end' of the available data in ringbuffer. No functional change. Signed-off-by: Kan Liang <kan.liang@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1516310792-208685-5-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Cleanup perf_mmap__push()Kan Liang2018-02-15
| | | | | | | | | | | | | | The first assignment for 'start' and 'end' is redundant. Signed-off-by: Kan Liang <kan.liang@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1516310792-208685-4-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* perf mmap: Recalculate size for overwrite modeKan Liang2018-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In perf_mmap__push(), the 'size' need to be recalculated, otherwise the invalid data might be pushed to the record in overwrite mode. The issue is introduced by commit 7fb4b407a124 ("perf mmap: Don't discard prev in backward mode"). When the ring buffer is full in overwrite mode, backward_rb_find_range() will be called to recalculate the 'start' and 'end'. The 'size' needs to be recalculated accordingly. Unconditionally recalculate the 'size', not just for full ring buffer in overwrite mode. Because: - There is no harmful to recalculate the 'size' for other cases. - The code of calculating 'start' and 'end' will be factored out later. The new function does not need to return 'size'. Signed-off-by: Kan Liang <kan.liang@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Fixes: 7fb4b407a124 ("perf mmap: Don't discard prev in backward mode") Link: http://lkml.kernel.org/r/1516310792-208685-3-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>