Messages in this thread | | | Date | Mon, 3 Jun 2013 11:41:33 +0200 | From | Alexander Gordeev <> | Subject | [PATCH RFC -tip 0/6] perf: IRQ-bound performance events |
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This patchset is against perf/core branch.
As Linux is able to measure task-bound and CPU-bound performance events there are no convenient means to monitor performance of an execution context which requires control and tuning probably most - interrupt service routines.
This series is an attempt to introduce IRQ-bound performance events - ones that only count in a context of a hardware interrupt handler.
The implementation is pretty straightforward: an IRQ-bound event is registered with the IRQ descriptor and gets enabled/disabled using new PMU callbacks: pmu_enable_irq() and pmu_disable_irq().
The series has not been tested thoroughly and is a concept proof rather than a decent implementation: no group events could be be loaded, inappropriate (i.e. software) events are not rejected, only Intel and AMD PMUs were tried for 'perf stat', only Intel PMU works with precise events. Perf tool changes are just a hack.
Yet, I would like first to ensure if the approach taken is not screwed and I did not miss anything vital. Not to mention if the change is wanted at all.
Below is a sample session on a machine with x2apic in cluster mode. IRQ number is passed using new argument -I <irq> (please nevermind '...process id '8'...' in the output for now):
# cat /proc/interrupts | grep ' 8:' 8: 23 0 0 0 21 0 0 0 23 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 27 0 0 0 23 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 IR-IO-APIC-edge rtc0 # ./tools/perf/perf stat -a -e L1-dcache-load-misses:k sleep 1 Performance counter stats for 'sleep 1':
124,849 L1-dcache-load-misses
1.001359403 seconds time elapsed
# ./tools/perf/perf stat -I 8 -a -e L1-dcache-load-misses:k sleep 1
Performance counter stats for process id '8':
0 L1-dcache-load-misses
1.001235781 seconds time elapsed
# ./tools/perf/perf stat -I 8 -a -e L1-dcache-load-misses:k hwclock --test Mon 03 Jun 2013 04:42:59 AM EDT -0.891274 seconds
Performance counter stats for process id '8':
Alexander Gordeev (6): perf/core: IRQ-bound performance events perf/x86: IRQ-bound performance events perf/x86/AMD PMU: IRQ-bound performance events perf/x86/Core PMU: IRQ-bound performance events perf/x86/Intel PMU: IRQ-bound performance events perf/tool: Hack 'pid' as 'irq' for sys_perf_event_open()
arch/x86/kernel/cpu/perf_event.c | 71 ++++++++++++++++++--- arch/x86/kernel/cpu/perf_event.h | 19 ++++++ arch/x86/kernel/cpu/perf_event_amd.c | 2 + arch/x86/kernel/cpu/perf_event_intel.c | 93 +++++++++++++++++++++++++-- arch/x86/kernel/cpu/perf_event_intel_ds.c | 5 +- arch/x86/kernel/cpu/perf_event_knc.c | 2 + arch/x86/kernel/cpu/perf_event_p4.c | 2 + arch/x86/kernel/cpu/perf_event_p6.c | 2 + include/linux/irq.h | 8 ++ include/linux/irqdesc.h | 3 + include/linux/perf_event.h | 16 +++++ include/uapi/linux/perf_event.h | 1 + kernel/events/core.c | 69 +++++++++++++++---- kernel/irq/Makefile | 1 + kernel/irq/handle.c | 4 + kernel/irq/irqdesc.c | 14 ++++ kernel/irq/perf_event.c | 100 +++++++++++++++++++++++++++++ tools/perf/builtin-record.c | 8 ++ tools/perf/builtin-stat.c | 8 ++ tools/perf/util/evlist.c | 4 +- tools/perf/util/evsel.c | 3 + tools/perf/util/evsel.h | 1 + tools/perf/util/target.c | 4 + tools/perf/util/thread_map.c | 16 +++++ 24 files changed, 422 insertions(+), 34 deletions(-) create mode 100644 kernel/irq/perf_event.c
-- 1.7.7.6
-- Regards, Alexander Gordeev agordeev@redhat.com
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