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| author | Peter Zijlstra <peterz@infradead.org> | 2016-07-06 07:18:30 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-08-10 11:13:28 (GMT) |
| commit | e48c178814b4a33f84f62d01f5a601ebd57fbba8 (patch) | |
| tree | b4ea583e868d79b8bc9140007703db2d9634da6c /include | |
| parent | 3e2c1a67d616dbc1034bc39448cd5f4aa3bd3cca (diff) | |
| download | linux-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')
| -rw-r--r-- | include/linux/perf_event.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 2b6b43c..529c41f 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 { |