From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
To: mpe@ellerman.id.au
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] powerpc/perf: Fix thersholding counter data for unknown type
Date: Sun, 9 Dec 2018 14:48:15 +0530 [thread overview]
Message-ID: <1544347095-19428-1-git-send-email-maddy@linux.vnet.ibm.com> (raw)
MMCRA[34:36] and MMCRA[38:44] expose the thresholding counter value.
Thresholding counter can be used to count latency cycles such as
load miss to reload. But threshold counter value is not relevant
when the sampled instruction type is unknown or reserved. Patch to
fix the thersholding counter value to zero when sampled instruction
type is unknown or reserved.
Fixes: 170a315f41c6('powerpc/perf: Support to export MMCRA[TEC*] field to userspace')
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
---
arch/powerpc/perf/isa207-common.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c
index 177de814286f..6a2f65d3d088 100644
--- a/arch/powerpc/perf/isa207-common.c
+++ b/arch/powerpc/perf/isa207-common.c
@@ -226,8 +226,13 @@ void isa207_get_mem_weight(u64 *weight)
u64 mmcra = mfspr(SPRN_MMCRA);
u64 exp = MMCRA_THR_CTR_EXP(mmcra);
u64 mantissa = MMCRA_THR_CTR_MANT(mmcra);
+ u64 sier = mfspr(SPRN_SIER);
+ u64 val = (sier & ISA207_SIER_TYPE_MASK) >> ISA207_SIER_TYPE_SHIFT;
- *weight = mantissa << (2 * exp);
+ if (val == 0 || val == 7)
+ *weight = 0;
+ else
+ *weight = mantissa << (2 * exp);
}
int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp)
--
2.7.4
next reply other threads:[~2018-12-09 9:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-09 9:18 Madhavan Srinivasan [this message]
2018-12-22 9:54 ` powerpc/perf: Fix thersholding counter data for unknown type Michael Ellerman
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