Re: [PATCH 2/4] perf vendor events arm64: AmpereOne: Mark affected STALL_* events impacted by errata

From: Ilkka Koskinen
Date: Thu Aug 10 2023 - 18:39:14 EST




On Fri, 4 Aug 2023, Ilkka Koskinen wrote:
On Fri, 4 Aug 2023, John Garry wrote:

On 03/08/2023 22:13, Ilkka Koskinen wrote:
Per errata AC03_CPU_29, STALL_SLOT_FRONTEND, STALL_FRONTEND, and STALL
events are not counting as expected. The follow up metrics patch will
include correct way to calculate the impacted events.

Signed-off-by: Ilkka Koskinen <ilkka@xxxxxxxxxxxxxxxxxxxxxx>

Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>

---
.../arch/arm64/ampere/ampereone/pipeline.json | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tools/perf/pmu-events/arch/arm64/ampere/ampereone/pipeline.json b/tools/perf/pmu-events/arch/arm64/ampere/ampereone/pipeline.json
index f9fae15f7555..711028377f3e 100644
--- a/tools/perf/pmu-events/arch/arm64/ampere/ampereone/pipeline.json
+++ b/tools/perf/pmu-events/arch/arm64/ampere/ampereone/pipeline.json
@@ -1,18 +1,24 @@
[
{
- "ArchStdEvent": "STALL_FRONTEND"
+ "ArchStdEvent": "STALL_FRONTEND",
+ "Errata": "Errata AC03_CPU_29",
+ "BriefDescription": "Impacted by errata, use metrics instead -"

why end with a '-'?

That's a great question! I wish, I remembered why I did that. Looking at other events with Errata field, they use '.'. I can fix those and submit the patchset again.

John, I took a look at it and it seems that if I use '.', perf will remove it. Here are two examples:

metrics.json:
"BriefDescription": "Impacted by errata, use metrics instead."

# perf list
[Impacted by errata, use metrics instead Spec update: Errata AC03_CPU_29]

vs.

"BriefDescription": "Impacted by errata, use metrics instead -"

# perf list

Impacted by errata, use metrics instead - Spec update: Errata AC03_CPU_29

---

So, I believe, I probably used the hyphen to make the 'perf list' output a little "prettier". Well, I just change to dot and it's fine.

Cheers, Ilkka



},
{
"ArchStdEvent": "STALL_BACKEND"
},
{
- "ArchStdEvent": "STALL"
+ "ArchStdEvent": "STALL",
+ "Errata": "Errata AC03_CPU_29",
+ "BriefDescription": "Impacted by errata, use metrics instead -"
},
{
"ArchStdEvent": "STALL_SLOT_BACKEND"
},
{
- "ArchStdEvent": "STALL_SLOT_FRONTEND"
+ "ArchStdEvent": "STALL_SLOT_FRONTEND",
+ "Errata": "Errata AC03_CPU_29",
+ "BriefDescription": "Impacted by errata, use metrics instead -"
},
{
"ArchStdEvent": "STALL_SLOT"