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powerpc/perf: Freeze PMC5/6 if we're not using them

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On Power8 we can freeze PMC5 and 6 if we're not using them. Normally they
run all the time.

As noticed by Anshuman, we should unfreeze them when we disable the PMU
as there are legacy tools which expect them to run all the time.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
CC: <stable@vger.kernel.org> [v3.10]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Ellerman
2013-06-28 18:15:12 +10:00
committed by Benjamin Herrenschmidt
parent 378a6ee99e
commit 7a7a41f9d5
3 changed files with 8 additions and 2 deletions
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5
arch/powerpc/perf/core-book3s.c
View File

@@ -75,6 +75,7 @@ static unsigned int freeze_events_kernel = MMCR0_FCS;
#define MMCR0_FCHV 0
#define MMCR0_PMCjCE MMCR0_PMCnCE
#define MMCR0_FC56 0
#define MMCR0_PMAO 0
#define SPRN_MMCRA SPRN_MMCR2
@@ -870,11 +871,11 @@ static void power_pmu_disable(struct pmu *pmu)
}
/*
* Set the 'freeze counters' bit, clear PMAO.
* Set the 'freeze counters' bit, clear PMAO/FC56.
*/
val = mfspr(SPRN_MMCR0);
val |= MMCR0_FC;
val &= ~MMCR0_PMAO;
val &= ~(MMCR0_PMAO | MMCR0_FC56);
/*
* The barrier is to make sure the mtspr has been

4
arch/powerpc/perf/power8-pmu.c
View File

@@ -391,6 +391,10 @@ static int power8_compute_mmcr(u64 event[], int n_ev,
if (pmc_inuse & 0x7c)
mmcr[0] |= MMCR0_PMCjCE;
/* If we're not using PMC 5 or 6, freeze them */
if (!(pmc_inuse & 0x60))
mmcr[0] |= MMCR0_FC56;
mmcr[1] = mmcr1;
mmcr[2] = mmcra;