sparc: Fix single-pcr perf event counter management.
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>
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index d3149ba..a4cc26b 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -927,6 +927,8 @@
sparc_perf_event_update(cp, &cp->hw,
cpuc->current_idx[i]);
cpuc->current_idx[i] = PIC_NO_INDEX;
+ if (cp->hw.state & PERF_HES_STOPPED)
+ cp->hw.state |= PERF_HES_ARCH;
}
}
}
@@ -959,10 +961,12 @@
enc = perf_event_get_enc(cpuc->events[i]);
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);
- else
+ } else {
cpuc->pcr[0] |= event_encoding(enc, idx);
+ hwc->state = 0;
+ }
}
out:
cpuc->pcr[0] |= cpuc->event[0]->hw.config_base;
@@ -988,6 +992,9 @@
cpuc->current_idx[i] = idx;
+ if (cp->hw.state & PERF_HES_ARCH)
+ continue;
+
sparc_pmu_start(cp, PERF_EF_RELOAD);
}
out:
@@ -1079,6 +1086,8 @@
event->hw.state = 0;
sparc_pmu_enable_event(cpuc, &event->hw, idx);
+
+ perf_event_update_userpage(event);
}
static void sparc_pmu_stop(struct perf_event *event, int flags)
@@ -1371,9 +1380,9 @@
cpuc->events[n0] = event->hw.event_base;
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))
- event->hw.state |= PERF_HES_STOPPED;
+ event->hw.state |= PERF_HES_ARCH;
/*
* If group events scheduling transaction was started,
