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authorPeter Zijlstra <peterz@infradead.org>2016-07-06 10:18:30 +0300
committerIngo Molnar <mingo@kernel.org>2016-08-10 14:13:28 +0300
commite48c178814b4a33f84f62d01f5a601ebd57fbba8 (patch)
treeb4ea583e868d79b8bc9140007703db2d9634da6c /include/linux/perf_event.h
parent3e2c1a67d616dbc1034bc39448cd5f4aa3bd3cca (diff)
downloadlinux-e48c178814b4a33f84f62d01f5a601ebd57fbba8.tar.xz
perf/core: Optimize perf_pmu_sched_task()
For perf record -b, which requires the pmu::sched_task callback the current code is rather expensive: 7.68% sched-pipe [kernel.vmlinux] [k] perf_pmu_sched_task 5.95% sched-pipe [kernel.vmlinux] [k] __switch_to 5.20% sched-pipe [kernel.vmlinux] [k] __intel_pmu_disable_all 3.95% sched-pipe perf [.] worker_thread The problem is that it will iterate all registered PMUs, most of which will not have anything to do. Avoid this by keeping an explicit list of PMUs that have requested the callback. The perf_sched_cb_{inc,dec}() functions already takes the required pmu argument, and now that these functions are no longer called from NMI context we can use them to manage a list. With this patch applied the function doesn't show up in the top 4 anymore (it dropped to 18th place). 6.67% sched-pipe [kernel.vmlinux] [k] __switch_to 6.18% sched-pipe [kernel.vmlinux] [k] __intel_pmu_disable_all 3.92% sched-pipe [kernel.vmlinux] [k] switch_mm_irqs_off 3.71% sched-pipe perf [.] worker_thread Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> 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> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/perf_event.h')
-rw-r--r--include/linux/perf_event.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2b6b43cc0dd5..529c41fa73c8 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -774,6 +774,9 @@ struct perf_cpu_context {
#ifdef CONFIG_CGROUP_PERF
struct perf_cgroup *cgrp;
#endif
+
+ struct list_head sched_cb_entry;
+ int sched_cb_usage;
};
struct perf_output_handle {