Messages in this thread Patch in this message | | | Date | Fri, 22 Jan 2010 16:50:53 +0100 | From | Peter Zijlstra <> | Subject | [PATCH 09/10] perf_event: x86: Optimize constraint weight computation |
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Add a weight member to the constraint structure and avoid recomputing the weight at runtime.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> --- arch/x86/kernel/cpu/perf_event.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c +++ linux-2.6/arch/x86/kernel/cpu/perf_event.c @@ -23,6 +23,7 @@ #include <linux/uaccess.h> #include <linux/highmem.h> #include <linux/cpu.h> +#include <linux/bitops.h> #include <asm/apic.h> #include <asm/stacktrace.h> @@ -76,6 +77,7 @@ struct event_constraint { }; int code; int cmask; + int weight; }; struct cpu_hw_events { @@ -96,6 +98,7 @@ struct cpu_hw_events { { .idxmsk64[0] = (n) }, \ .code = (c), \ .cmask = (m), \ + .weight = HWEIGHT64((u64)(n)), \ } #define INTEL_EVENT_CONSTRAINT(c, n) \ @@ -1245,8 +1248,7 @@ static inline int is_x86_event(struct pe static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) { - int i, j , w, num; - int weight, wmax; + int i, j, w, num, wmax; struct event_constraint *c, *constraints[X86_PMC_IDX_MAX]; unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; struct hw_perf_event *hwc; @@ -1323,8 +1325,7 @@ static int x86_schedule_events(struct cp c = constraints[i]; hwc = &cpuc->event_list[i]->hw; - weight = bitmap_weight(c->idxmsk, X86_PMC_IDX_MAX); - if (weight != w) + if (c->weight != w) continue; for_each_bit(j, c->idxmsk, X86_PMC_IDX_MAX) { --
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