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| author |   Peter Zijlstra <peterz@infradead.org> | 2019-03-14 13:01:14 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2019-04-03 09:25:31 +0200 |
| commit | c090cb70c6152fc97ce91242789d7c322109f1a1 (patch) | |
| tree | aa422c4c19f89076a054d65b5c3087a764805066 /arch/x86/events | |
| parent | perf/x86: Remove PERF_X86_EVENT_COMMITTED (diff) | |
| download | linux-dev-c090cb70c6152fc97ce91242789d7c322109f1a1.tar.xz linux-dev-c090cb70c6152fc97ce91242789d7c322109f1a1.zip | |
perf/x86/intel: Optimize intel_get_excl_constraints()
Avoid the POPCNT by noting we can decrement the weight for each
cleared bit.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Stephane Eranian <eranian@google.com>
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: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/events')
| -rw-r--r-- | arch/x86/events/intel/core.c | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 879ab540fd05..a80015fa8aed 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -2838,7 +2838,7 @@ intel_get_excl_constraints(struct cpu_hw_events *cpuc, struct perf_event *event, struct intel_excl_cntrs *excl_cntrs = cpuc->excl_cntrs; struct intel_excl_states *xlo; int tid = cpuc->excl_thread_id; - int is_excl, i; + int is_excl, i, w; /* * validating a group does not require @@ -2894,36 +2894,40 @@ intel_get_excl_constraints(struct cpu_hw_events *cpuc, struct perf_event *event, * SHARED : sibling counter measuring non-exclusive event * UNUSED : sibling counter unused */ + w = c->weight; for_each_set_bit(i, c->idxmsk, X86_PMC_IDX_MAX) { /* * exclusive event in sibling counter * our corresponding counter cannot be used * regardless of our event */ - if (xlo->state[i] == INTEL_EXCL_EXCLUSIVE) + if (xlo->state[i] == INTEL_EXCL_EXCLUSIVE) { __clear_bit(i, c->idxmsk); + w--; + continue; + } /* * if measuring an exclusive event, sibling * measuring non-exclusive, then counter cannot * be used */ - if (is_excl && xlo->state[i] == INTEL_EXCL_SHARED) + if (is_excl && xlo->state[i] == INTEL_EXCL_SHARED) { __clear_bit(i, c->idxmsk); + w--; + continue; + } } /* - * recompute actual bit weight for scheduling algorithm - */ - c->weight = hweight64(c->idxmsk64); - - /* * if we return an empty mask, then switch * back to static empty constraint to avoid * the cost of freeing later on */ - if (c->weight == 0) + if (!w) c = &emptyconstraint; + c->weight = w; + return c; } |