diff options
| author | Ravi Bangoria <ravi.bangoria@amd.com> | 2025-01-15 05:44:32 +0000 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2025-02-03 11:46:05 +0100 |
| commit | 598bdf4fefff5af4ce6d26d16f7b2a20808fc4cb (patch) | |
| tree | faa21ec146c81863f1a5403c8ca4e49b7b43b2fe | |
| parent | 88c7bcad71c83f52f24108dedcecae0d18dbc627 (diff) | |
perf/amd/ibs: Fix ->config to sample period calculation for OP PMU
Instead of using standard perf_event_attr->freq=0 and ->sample_period
fields, IBS event in 'sample period mode' can also be opened by setting
period value directly in perf_event_attr->config in a MaxCnt bit-field
format.
IBS OP MaxCnt bits are defined as:
(high bits) IbsOpCtl[26:20] = IbsOpMaxCnt[26:20]
(low bits) IbsOpCtl[15:0] = IbsOpMaxCnt[19:4]
Perf event sample period can be derived from MaxCnt bits as:
sample_period = (high bits) | ((low_bits) << 4);
However, current code just masks MaxCnt bits and shifts all of them,
including high bits, which is incorrect. Fix it.
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/r/20250115054438.1021-4-ravi.bangoria@amd.com
| -rw-r--r-- | arch/x86/events/amd/ibs.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c index bd8919e7c3b1..f95542b75b91 100644 --- a/arch/x86/events/amd/ibs.c +++ b/arch/x86/events/amd/ibs.c @@ -271,7 +271,7 @@ static int perf_ibs_init(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; struct perf_ibs *perf_ibs; - u64 max_cnt, config; + u64 config; int ret; perf_ibs = get_ibs_pmu(event->attr.type); @@ -313,10 +313,19 @@ static int perf_ibs_init(struct perf_event *event) if (!hwc->sample_period) hwc->sample_period = 0x10; } else { - max_cnt = config & perf_ibs->cnt_mask; + u64 period = 0; + + if (perf_ibs == &perf_ibs_op) { + period = (config & IBS_OP_MAX_CNT) << 4; + if (ibs_caps & IBS_CAPS_OPCNTEXT) + period |= config & IBS_OP_MAX_CNT_EXT_MASK; + } else { + period = (config & IBS_FETCH_MAX_CNT) << 4; + } + config &= ~perf_ibs->cnt_mask; - event->attr.sample_period = max_cnt << 4; - hwc->sample_period = event->attr.sample_period; + event->attr.sample_period = period; + hwc->sample_period = period; } if (!hwc->sample_period) |