* [PATCH] powerpc/perf: Fix PMU constraint check for EBB events
@ 2021-04-06 16:16 Athira Rajeev
2021-04-10 14:28 ` Michael Ellerman
0 siblings, 1 reply; 2+ messages in thread
From: Athira Rajeev @ 2021-04-06 16:16 UTC (permalink / raw)
To: mpe; +Cc: cascardo, maddy, linuxppc-dev
The power PMU group constraints includes check for EBB events
to make sure all events in a group must agree on EBB. This
will prevent scheduling EBB and non-EBB events together.
But in the existing check, settings for constraint mask and
value is interchanged. Patch fixes the same.
Before the patch, PMU selftest "cpu_event_pinned_vs_ebb_test"
fails with below in dmesg logs. This happens because EBB event
gets enabled along with a non-EBB cpu event.
<<>>
[35600.453346] cpu_event_pinne[41326]: illegal instruction (4)
at 10004a18 nip 10004a18 lr 100049f8 code 1 in
cpu_event_pinned_vs_ebb_test[10000000+10000]
<<>>
Test results after the patch:
./pmu/ebb/cpu_event_pinned_vs_ebb_test
test: cpu_event_pinned_vs_ebb
tags: git_version:v5.12-rc5-93-gf28c3125acd3-dirty
Binding to cpu 8
EBB Handler is at 0x100050c8
read error on event 0x7fffe6bd4040!
PM_RUN_INST_CMPL: result 9872 running/enabled 37930432
success: cpu_event_pinned_vs_ebb
Fixes: 4df489991182 ("powerpc/perf: Add power8 EBB support")
Reported-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
---
arch/powerpc/perf/isa207-common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c
index e4f577da33d8..8b5eeb6fb2fb 100644
--- a/arch/powerpc/perf/isa207-common.c
+++ b/arch/powerpc/perf/isa207-common.c
@@ -447,8 +447,8 @@ int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp,
* EBB events are pinned & exclusive, so this should never actually
* hit, but we leave it as a fallback in case.
*/
- mask |= CNST_EBB_VAL(ebb);
- value |= CNST_EBB_MASK;
+ mask |= CNST_EBB_MASK;
+ value |= CNST_EBB_VAL(ebb);
*maskp = mask;
*valp = value;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] powerpc/perf: Fix PMU constraint check for EBB events
2021-04-06 16:16 [PATCH] powerpc/perf: Fix PMU constraint check for EBB events Athira Rajeev
@ 2021-04-10 14:28 ` Michael Ellerman
0 siblings, 0 replies; 2+ messages in thread
From: Michael Ellerman @ 2021-04-10 14:28 UTC (permalink / raw)
To: Athira Rajeev, mpe; +Cc: cascardo, maddy, linuxppc-dev
On Tue, 6 Apr 2021 12:16:01 -0400, Athira Rajeev wrote:
> The power PMU group constraints includes check for EBB events
> to make sure all events in a group must agree on EBB. This
> will prevent scheduling EBB and non-EBB events together.
> But in the existing check, settings for constraint mask and
> value is interchanged. Patch fixes the same.
>
> Before the patch, PMU selftest "cpu_event_pinned_vs_ebb_test"
> fails with below in dmesg logs. This happens because EBB event
> gets enabled along with a non-EBB cpu event.
>
> [...]
Applied to powerpc/next.
[1/1] powerpc/perf: Fix PMU constraint check for EBB events
https://git.kernel.org/powerpc/c/10f8f96179ecc7f69c927f6d231f6d02736cea83
cheers
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2021-04-06 16:16 [PATCH] powerpc/perf: Fix PMU constraint check for EBB events Athira Rajeev
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