perf stat: Use affinity for closing file descriptors (7736627b) · Commits · 戴 / test

Closing a perf fd can also trigger an IPI to the target CPU. Use the same affinity technique as we use for reading/enabling events to closing to optimize the CPU transitions. Before on a large test case with 94 CPUs: % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 32.56 3.085463 50 61483 close After: 10.54 0.735704 11 61485 close Signed-off-by:

Andi Kleen <ak@linux.intel.com> Acked-by:

Jiri Olsa <jolsa@kernel.org> Link: http://lore.kernel.org/lkml/20191121001522.180827-8-andi@firstfloor.org Signed-off-by:

Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evlist.c

+29 −2

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@
		#include "debug.h"
		#include "units.h"
		#include <internal/lib.h> // page_size
		#include "affinity.h"
		#include "../perf.h"
		#include "asm/bug.h"
		#include "bpf-event.h"
		@@ -1169,9 +1170,35 @@ void perf_evlist__set_selected(struct evlist *evlist,
		void evlist__close(struct evlist *evlist)
		{
		struct evsel *evsel;
		struct affinity affinity;
		int cpu, i;

		/*
		* With perf record core.cpus is usually NULL.
		* Use the old method to handle this for now.
		*/
		if (!evlist->core.cpus) {
		evlist__for_each_entry_reverse(evlist, evsel)
		evsel__close(evsel);
		return;
		}

		if (affinity__setup(&affinity) < 0)
		return;
		evlist__for_each_cpu(evlist, i, cpu) {
		affinity__set(&affinity, cpu);

		evlist__for_each_entry_reverse(evlist, evsel) {
		if (evsel__cpu_iter_skip(evsel, cpu))
		continue;
		perf_evsel__close_cpu(&evsel->core, evsel->cpu_iter - 1);
		}
		}
		affinity__cleanup(&affinity);
		evlist__for_each_entry_reverse(evlist, evsel) {
		perf_evsel__free_fd(&evsel->core);
		perf_evsel__free_id(&evsel->core);
		}
		}

		static int perf_evlist__create_syswide_maps(struct evlist *evlist)

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