Commit cfdc3170 authored by David S. Miller's avatar David S. Miller
Browse files

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: default avatarDavid S. Miller <davem@davemloft.net>
parent 7c26701a

arch/sparc/kernel/perf_event.c

+13 −4
Original line number Diff line number Diff line
@@ -927,6 +927,8 @@ static void read_in_all_counters(struct cpu_hw_events *cpuc) 
			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 @@ static void calculate_single_pcr(struct cpu_hw_events *cpuc) 


		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 @@ static void calculate_multiple_pcrs(struct cpu_hw_events *cpuc) 


		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 @@ static void sparc_pmu_start(struct perf_event *event, int flags) 
	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 @@ static int sparc_pmu_add(struct perf_event *event, int ef_flags) 
	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,

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