diff options
| author | Robert Richter <robert.richter@amd.com> | 2012-04-02 20:19:10 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-05-09 15:23:13 +0200 |
| commit | 6accb9cf76080422d400a641d9068b6b2a2c216f (patch) | |
| tree | 3774a7b43cb513761924209f5d51b1a497fcd3d2 /arch | |
| parent | 7bf352384fda3f678a283928c6c5b2cd9da877e4 (diff) | |
perf/x86-ibs: Fix frequency profiling
Fixing profiling at a fixed frequency, in this case the freq value and
sample period was setup incorrectly. Since sampling periods are
adjusted we also allow periods that have lower 4 bits set.
Another fix is the setup of the hw counter: If we modify
hwc->sample_period, we also need to update hwc->last_period and
hwc->period_left.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1333390758-10893-5-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_amd_ibs.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/arch/x86/kernel/cpu/perf_event_amd_ibs.c index ebf169fe40ef..bc401bd9f14a 100644 --- a/arch/x86/kernel/cpu/perf_event_amd_ibs.c +++ b/arch/x86/kernel/cpu/perf_event_amd_ibs.c @@ -162,9 +162,16 @@ static int perf_ibs_init(struct perf_event *event) if (config & perf_ibs->cnt_mask) /* raw max_cnt may not be set */ return -EINVAL; - if (hwc->sample_period & 0x0f) - /* lower 4 bits can not be set in ibs max cnt */ + if (!event->attr.sample_freq && hwc->sample_period & 0x0f) + /* + * lower 4 bits can not be set in ibs max cnt, + * but allowing it in case we adjust the + * sample period to set a frequency. + */ return -EINVAL; + hwc->sample_period &= ~0x0FULL; + if (!hwc->sample_period) + hwc->sample_period = 0x10; } else { max_cnt = config & perf_ibs->cnt_mask; config &= ~perf_ibs->cnt_mask; @@ -175,6 +182,13 @@ static int perf_ibs_init(struct perf_event *event) if (!hwc->sample_period) return -EINVAL; + /* + * If we modify hwc->sample_period, we also need to update + * hwc->last_period and hwc->period_left. + */ + hwc->last_period = hwc->sample_period; + local64_set(&hwc->period_left, hwc->sample_period); + hwc->config_base = perf_ibs->msr; hwc->config = config; |