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sparc: Fix single-pcr perf event counter management.

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It is important to clear the hw->state value for non-stopped events
when they are added into the PMU.  Otherwise when the event is
scheduled out, we won't read the counter because HES_UPTODATE is still
set.  This breaks 'perf stat' and similar use cases, causing all the
events to show zero.

This worked for multi-pcr because we make explicit sparc_pmu_start()
calls in calculate_multiple_pcrs().  calculate_single_pcr() doesn't do
this because the idea there is to accumulate all of the counter
settings into the single pcr value.  So we have to add explicit
hw->state handling there.

Like x86, we use the PERF_HES_ARCH bit to track truly stopped events
so that we don't accidently start them on a reload.

Related to all of this, sparc_pmu_start() is missing a userpage update
so add it.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2018-10-12 10:31:58 -07:00
parent 7c26701a77
commit cfdc3170d2
1 changed files with 13 additions and 4 deletions
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17
arch/sparc/kernel/perf_event.c
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@ -927,6 +927,8 @@ static void read_in_all_counters(struct cpu_hw_events *cpuc)
sparc_perf_event_update(cp, &cp->hw, sparc_perf_event_update(cp, &cp->hw,
cpuc->current_idx[i]); cpuc->current_idx[i]);
cpuc->current_idx[i] = PIC_NO_INDEX; cpuc->current_idx[i] = PIC_NO_INDEX;
if (cp->hw.state & PERF_HES_STOPPED)
cp->hw.state |= PERF_HES_ARCH;
} }
} }
} }
@ -959,10 +961,12 @@ static void calculate_single_pcr(struct cpu_hw_events *cpuc)
enc = perf_event_get_enc(cpuc->events[i]); enc = perf_event_get_enc(cpuc->events[i]);
cpuc->pcr[0] &= ~mask_for_index(idx); cpuc->pcr[0] &= ~mask_for_index(idx);
if (hwc->state & PERF_HES_STOPPED) if (hwc->state & PERF_HES_ARCH) {
cpuc->pcr[0] |= nop_for_index(idx); cpuc->pcr[0] |= nop_for_index(idx);
else } else {
cpuc->pcr[0] |= event_encoding(enc, idx); cpuc->pcr[0] |= event_encoding(enc, idx);
hwc->state = 0;
}
} }
out: out:
cpuc->pcr[0] |= cpuc->event[0]->hw.config_base; cpuc->pcr[0] |= cpuc->event[0]->hw.config_base;
@ -988,6 +992,9 @@ static void calculate_multiple_pcrs(struct cpu_hw_events *cpuc)
cpuc->current_idx[i] = idx; cpuc->current_idx[i] = idx;
if (cp->hw.state & PERF_HES_ARCH)
continue;
sparc_pmu_start(cp, PERF_EF_RELOAD); sparc_pmu_start(cp, PERF_EF_RELOAD);
} }
out: out:
@ -1079,6 +1086,8 @@ static void sparc_pmu_start(struct perf_event *event, int flags)
event->hw.state = 0; event->hw.state = 0;
sparc_pmu_enable_event(cpuc, &event->hw, idx); sparc_pmu_enable_event(cpuc, &event->hw, idx);
perf_event_update_userpage(event);
} }
static void sparc_pmu_stop(struct perf_event *event, int flags) static void sparc_pmu_stop(struct perf_event *event, int flags)
@ -1371,9 +1380,9 @@ static int sparc_pmu_add(struct perf_event *event, int ef_flags)
cpuc->events[n0] = event->hw.event_base; cpuc->events[n0] = event->hw.event_base;
cpuc->current_idx[n0] = PIC_NO_INDEX; cpuc->current_idx[n0] = PIC_NO_INDEX;
event->hw.state = PERF_HES_UPTODATE; event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
if (!(ef_flags & PERF_EF_START)) if (!(ef_flags & PERF_EF_START))
event->hw.state |= PERF_HES_STOPPED; event->hw.state |= PERF_HES_ARCH;
/* /*
* If group events scheduling transaction was started, * If group events scheduling transaction was started,