Messages in this thread Patch in this message | | | Date | Mon, 5 Oct 2020 10:25:16 +0200 | From | Peter Zijlstra <> | Subject | [PATCH] perf/x86: Fix n_pair for cancelled txn |
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On Fri, Oct 02, 2020 at 04:10:42PM -0500, Kim Phillips wrote: > Tested-by: Kim Phillips <kim.phillips@amd.com>
--- Subject: perf/x86: Fix n_pair for cancelled txn From: Peter Zijlstra <peterz@infradead.org> Date: Mon Oct 5 10:09:06 CEST 2020
Kan reported that n_metric gets corrupted for cancelled transactions; a similar issue exists for n_pair for AMD's Large Increment thing.
The problem was confirmed and confirmed fixed by Kim using:
sudo perf stat -e "{cycles,cycles,cycles,cycles}:D" -a sleep 10 &
# should succeed: sudo perf stat -e "{fp_ret_sse_avx_ops.all}:D" -a workload
# should fail: sudo perf stat -e "{fp_ret_sse_avx_ops.all,fp_ret_sse_avx_ops.all,cycles}:D" -a workload
# previously failed, now succeeds with this patch: sudo perf stat -e "{fp_ret_sse_avx_ops.all}:D" -a workload
Fixes: 5738891229a2 ("perf/x86/amd: Add support for Large Increment per Cycle Events") Reported-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Kim Phillips <kim.phillips@amd.com> --- arch/x86/events/core.c | 6 +++++- arch/x86/events/perf_event.h | 1 + 2 files changed, 6 insertions(+), 1 deletion(-)
--- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1089,8 +1089,10 @@ static int collect_event(struct cpu_hw_e return -EINVAL; cpuc->event_list[n] = event; - if (is_counter_pair(&event->hw)) + if (is_counter_pair(&event->hw)) { cpuc->n_pair++; + cpuc->n_txn_pair++; + } return 0; } @@ -2062,6 +2064,7 @@ static void x86_pmu_start_txn(struct pmu perf_pmu_disable(pmu); __this_cpu_write(cpu_hw_events.n_txn, 0); + __this_cpu_write(cpu_hw_events.n_txn_pair, 0); } /* @@ -2087,6 +2090,7 @@ static void x86_pmu_cancel_txn(struct pm */ __this_cpu_sub(cpu_hw_events.n_added, __this_cpu_read(cpu_hw_events.n_txn)); __this_cpu_sub(cpu_hw_events.n_events, __this_cpu_read(cpu_hw_events.n_txn)); + __this_cpu_sub(cpu_hw_events.n_pair, __this_cpu_read(cpu_hw_events.n_txn_pair)); perf_pmu_enable(pmu); } --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -235,6 +235,7 @@ struct cpu_hw_events { they've never been enabled yet */ int n_txn; /* the # last events in the below arrays; added in the current transaction */ + int n_txn_pair; int assign[X86_PMC_IDX_MAX]; /* event to counter assignment */ u64 tags[X86_PMC_IDX_MAX];
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