Peter Zijlstra b0ebeb5956 perf: Optimize perf_cgroup_switch() ... [ Upstream commit f06cc667f7 ] Namhyung reported that bd27568117 ("perf: Rewrite core context handling") regresses context switch overhead when perf-cgroup is in use together with 'slow' PMUs like uncore. Specifically, perf_cgroup_switch()'s perf_ctx_disable() / ctx_sched_out() etc.. all iterate the full list of active PMUs for that CPU, even if they don't have cgroup events. Previously there was cgrp_cpuctx_list which linked the relevant PMUs together, but that got lost in the rework. Instead of re-instruducing a similar list, let the perf_event_pmu_context iteration skip those that do not have cgroup events. This avoids growing multiple versions of the perf_event_pmu_context iteration. Measured performance (on a slightly different patch): Before) $ taskset -c 0 ./perf bench sched pipe -l 10000 -G AAA,BBB # Running 'sched/pipe' benchmark: # Executed 10000 pipe operations between two processes Total time: 0.901 [sec] 90.128700 usecs/op 11095 ops/sec After) $ taskset -c 0 ./perf bench sched pipe -l 10000 -G AAA,BBB # Running 'sched/pipe' benchmark: # Executed 10000 pipe operations between two processes Total time: 0.065 [sec] 6.560100 usecs/op 152436 ops/sec Fixes: bd27568117 ("perf: Rewrite core context handling") Reported-by: Namhyung Kim <namhyung@kernel.org> Debugged-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20231009210425.GC6307@noisy.programming.kicks-ass.net Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-11-20 11:58:53 +01:00
..
callchain.c	uaccess: remove CONFIG_SET_FS	2022-02-25 09:36:06 +01:00
core.c	perf: Optimize perf_cgroup_switch()	2023-11-20 11:58:53 +01:00
hw_breakpoint.c	perf/hw_breakpoint: Remove arch breakpoint hooks	2023-08-16 23:54:50 +10:00
hw_breakpoint_test.c	perf/hw_breakpoint: remove MODULE_LICENSE in non-modules	2023-04-13 13:13:52 -07:00
internal.h	perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled	2022-04-19 21:15:42 +02:00
Makefile	perf/hw_breakpoint: Add KUnit test for constraints accounting	2022-08-30 10:56:20 +02:00
ring_buffer.c	perf/ring_buffer: Use local_try_cmpxchg in __perf_output_begin	2023-07-10 09:52:36 +02:00
uprobes.c	mmu_notifiers: don't invalidate secondary TLBs as part of mmu_notifier_invalidate_range_end()	2023-08-18 10:12:41 -07:00