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The kernel perf subsystem has to IPI to the target CPU for many operations. On systems with many CPUs and when managing many events the overhead can be dominated by lots of IPIs. An alternative is to set up CPU affinity in the perf tool, then set up all the events for that CPU, and then move on to the next CPU. Add some affinity management infrastructure to enable such a model. Used in followon patches. Committer notes: Use zfree() in some places, add missing stdbool.h header, some minor coding style changes. Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: http://lore.kernel.org/lkml/20191121001522.180827-3-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
17 lines
362 B
C
17 lines
362 B
C
// SPDX-License-Identifier: GPL-2.0
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#ifndef PERF_AFFINITY_H
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#define PERF_AFFINITY_H 1
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#include <stdbool.h>
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struct affinity {
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unsigned long *orig_cpus;
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unsigned long *sched_cpus;
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bool changed;
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};
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void affinity__cleanup(struct affinity *a);
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void affinity__set(struct affinity *a, int cpu);
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int affinity__setup(struct affinity *a);
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#endif // PERF_AFFINITY_H
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