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authorLinus Torvalds <torvalds@linux-foundation.org>2012-03-20 13:29:15 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-20 13:29:15 -0400
commit9c2b957db1772ebf942ae7a9346b14eba6c8ca66 (patch)
tree0dbb83e57260ea7fc0dc421f214d5f1b26262005 /arch/x86/kernel/cpu/perf_event_intel_ds.c
parent0bbfcaff9b2a69c71a95e6902253487ab30cb498 (diff)
parentbea95c152dee1791dd02cbc708afbb115bb00f9a (diff)
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events changes for v3.4 from Ingo Molnar: - New "hardware based branch profiling" feature both on the kernel and the tooling side, on CPUs that support it. (modern x86 Intel CPUs with the 'LBR' hardware feature currently.) This new feature is basically a sophisticated 'magnifying glass' for branch execution - something that is pretty difficult to extract from regular, function histogram centric profiles. The simplest mode is activated via 'perf record -b', and the result looks like this in perf report: $ perf record -b any_call,u -e cycles:u branchy $ perf report -b --sort=symbol 52.34% [.] main [.] f1 24.04% [.] f1 [.] f3 23.60% [.] f1 [.] f2 0.01% [k] _IO_new_file_xsputn [k] _IO_file_overflow 0.01% [k] _IO_vfprintf_internal [k] _IO_new_file_xsputn 0.01% [k] _IO_vfprintf_internal [k] strchrnul 0.01% [k] __printf [k] _IO_vfprintf_internal 0.01% [k] main [k] __printf This output shows from/to branch columns and shows the highest percentage (from,to) jump combinations - i.e. the most likely taken branches in the system. "branches" can also include function calls and any other synchronous and asynchronous transitions of the instruction pointer that are not 'next instruction' - such as system calls, traps, interrupts, etc. This feature comes with (hopefully intuitive) flat ascii and TUI support in perf report. - Various 'perf annotate' visual improvements for us assembly junkies. It will now recognize function calls in the TUI and by hitting enter you can follow the call (recursively) and back, amongst other improvements. - Multiple threads/processes recording support in perf record, perf stat, perf top - which is activated via a comma-list of PIDs: perf top -p 21483,21485 perf stat -p 21483,21485 -ddd perf record -p 21483,21485 - Support for per UID views, via the --uid paramter to perf top, perf report, etc. For example 'perf top --uid mingo' will only show the tasks that I am running, excluding other users, root, etc. - Jump label restructurings and improvements - this includes the factoring out of the (hopefully much clearer) include/linux/static_key.h generic facility: struct static_key key = STATIC_KEY_INIT_FALSE; ... if (static_key_false(&key)) do unlikely code else do likely code ... static_key_slow_inc(); ... static_key_slow_inc(); ... The static_key_false() branch will be generated into the code with as little impact to the likely code path as possible. the static_key_slow_*() APIs flip the branch via live kernel code patching. This facility can now be used more widely within the kernel to micro-optimize hot branches whose likelihood matches the static-key usage and fast/slow cost patterns. - SW function tracer improvements: perf support and filtering support. - Various hardenings of the perf.data ABI, to make older perf.data's smoother on newer tool versions, to make new features integrate more smoothly, to support cross-endian recording/analyzing workflows better, etc. - Restructuring of the kprobes code, the splitting out of 'optprobes', and a corner case bugfix. - Allow the tracing of kernel console output (printk). - Improvements/fixes to user-space RDPMC support, allowing user-space self-profiling code to extract PMU counts without performing any system calls, while playing nice with the kernel side. - 'perf bench' improvements - ... and lots of internal restructurings, cleanups and fixes that made these features possible. And, as usual this list is incomplete as there were also lots of other improvements * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (120 commits) perf report: Fix annotate double quit issue in branch view mode perf report: Remove duplicate annotate choice in branch view mode perf/x86: Prettify pmu config literals perf report: Enable TUI in branch view mode perf report: Auto-detect branch stack sampling mode perf record: Add HEADER_BRANCH_STACK tag perf record: Provide default branch stack sampling mode option perf tools: Make perf able to read files from older ABIs perf tools: Fix ABI compatibility bug in print_event_desc() perf tools: Enable reading of perf.data files from different ABI rev perf: Add ABI reference sizes perf report: Add support for taken branch sampling perf record: Add support for sampling taken branch perf tools: Add code to support PERF_SAMPLE_BRANCH_STACK x86/kprobes: Split out optprobe related code to kprobes-opt.c x86/kprobes: Fix a bug which can modify kernel code permanently x86/kprobes: Fix instruction recovery on optimized path perf: Add callback to flush branch_stack on context switch perf: Disable PERF_SAMPLE_BRANCH_* when not supported perf/x86: Add LBR software filter support for Intel CPUs ...
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel_ds.c')
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel_ds.c22
1 files changed, 5 insertions, 17 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index d6bd49faa40c..7f64df19e7dd 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -3,6 +3,7 @@
3#include <linux/slab.h> 3#include <linux/slab.h>
4 4
5#include <asm/perf_event.h> 5#include <asm/perf_event.h>
6#include <asm/insn.h>
6 7
7#include "perf_event.h" 8#include "perf_event.h"
8 9
@@ -439,9 +440,6 @@ void intel_pmu_pebs_enable(struct perf_event *event)
439 hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT; 440 hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT;
440 441
441 cpuc->pebs_enabled |= 1ULL << hwc->idx; 442 cpuc->pebs_enabled |= 1ULL << hwc->idx;
442
443 if (x86_pmu.intel_cap.pebs_trap && event->attr.precise_ip > 1)
444 intel_pmu_lbr_enable(event);
445} 443}
446 444
447void intel_pmu_pebs_disable(struct perf_event *event) 445void intel_pmu_pebs_disable(struct perf_event *event)
@@ -454,9 +452,6 @@ void intel_pmu_pebs_disable(struct perf_event *event)
454 wrmsrl(MSR_IA32_PEBS_ENABLE, cpuc->pebs_enabled); 452 wrmsrl(MSR_IA32_PEBS_ENABLE, cpuc->pebs_enabled);
455 453
456 hwc->config |= ARCH_PERFMON_EVENTSEL_INT; 454 hwc->config |= ARCH_PERFMON_EVENTSEL_INT;
457
458 if (x86_pmu.intel_cap.pebs_trap && event->attr.precise_ip > 1)
459 intel_pmu_lbr_disable(event);
460} 455}
461 456
462void intel_pmu_pebs_enable_all(void) 457void intel_pmu_pebs_enable_all(void)
@@ -475,17 +470,6 @@ void intel_pmu_pebs_disable_all(void)
475 wrmsrl(MSR_IA32_PEBS_ENABLE, 0); 470 wrmsrl(MSR_IA32_PEBS_ENABLE, 0);
476} 471}
477 472
478#include <asm/insn.h>
479
480static inline bool kernel_ip(unsigned long ip)
481{
482#ifdef CONFIG_X86_32
483 return ip > PAGE_OFFSET;
484#else
485 return (long)ip < 0;
486#endif
487}
488
489static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs) 473static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs)
490{ 474{
491 struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); 475 struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
@@ -572,6 +556,7 @@ static void __intel_pmu_pebs_event(struct perf_event *event,
572 * both formats and we don't use the other fields in this 556 * both formats and we don't use the other fields in this
573 * routine. 557 * routine.
574 */ 558 */
559 struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
575 struct pebs_record_core *pebs = __pebs; 560 struct pebs_record_core *pebs = __pebs;
576 struct perf_sample_data data; 561 struct perf_sample_data data;
577 struct pt_regs regs; 562 struct pt_regs regs;
@@ -602,6 +587,9 @@ static void __intel_pmu_pebs_event(struct perf_event *event,
602 else 587 else
603 regs.flags &= ~PERF_EFLAGS_EXACT; 588 regs.flags &= ~PERF_EFLAGS_EXACT;
604 589
590 if (has_branch_stack(event))
591 data.br_stack = &cpuc->lbr_stack;
592
605 if (perf_event_overflow(event, &data, &regs)) 593 if (perf_event_overflow(event, &data, &regs))
606 x86_pmu_stop(event, 0); 594 x86_pmu_stop(event, 0);
607} 595}