diff options
| author | Robert Richter <robert.richter@amd.com> | 2009-04-29 12:47:22 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-04-29 14:51:13 +0200 |
| commit | 4b7bfd0d276da3a006d37e85d3cf900d7a14ae2a (patch) | |
| tree | ed4fe623afebdeb17e0a9ccc833f2154cd815991 /arch | |
| parent | a29aa8a7ff93e4196d558036928597e68337dd8d (diff) | |
perf_counter, x86: return raw count with x86_perf_counter_update()
To check on AMD cpus if a counter overflows, the upper bit of the raw
counter value must be checked. This value is already internally
available in x86_perf_counter_update(). Now, the value is returned so
that it can be used directly to check for overflows.
[ Impact: micro-optimization ]
Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1241002046-8832-26-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index f4d59d4cf3f..a8a53abd706 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -132,7 +132,7 @@ static u64 amd_pmu_raw_event(u64 event) * Can only be executed on the CPU where the counter is active. * Returns the delta events processed. */ -static void +static u64 x86_perf_counter_update(struct perf_counter *counter, struct hw_perf_counter *hwc, int idx) { @@ -165,6 +165,8 @@ again: atomic64_add(delta, &counter->count); atomic64_sub(delta, &hwc->period_left); + + return new_raw_count; } static atomic_t num_counters; @@ -785,8 +787,7 @@ static int amd_pmu_handle_irq(struct pt_regs *regs, int nmi) continue; counter = cpuc->counters[idx]; hwc = &counter->hw; - x86_perf_counter_update(counter, hwc, idx); - val = atomic64_read(&hwc->prev_count); + val = x86_perf_counter_update(counter, hwc, idx); if (val & (1ULL << (x86_pmu.counter_bits - 1))) continue; /* counter overflow */ |