perf_event: x86: Optimize the fast path a little more

Remove num from the fast path and save a few ops.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <20100122155536.056430539@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 2c22ce4fa78470a3783df02837a09990c7024f4a..33c889ff21ae1880726105fb511409672c874d52 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1245,9 +1245,9 @@ static inline int is_x86_event(struct perf_event *event)
 
 static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
 {
-       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)];
+       int i, j, w, wmax, num = 0;
        struct hw_perf_event *hwc;
 
        bitmap_zero(used_mask, X86_PMC_IDX_MAX);
@@ -1260,7 +1260,7 @@ static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
        /*
         * fastpath, try to reuse previous register
         */
-       for (i = 0, num = n; i < n; i++, num--) {
+       for (i = 0; i < n; i++) {
                hwc = &cpuc->event_list[i]->hw;
                c = constraints[i];
 
@@ -1288,7 +1288,7 @@ static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
                if (assign)
                        assign[i] = hwc->idx;
        }
-       if (!num)
+       if (i == n)
                goto done;
 
        /*