Re: [External] : [RFC PATCH v2 1/6] perf vendor events arm64: Add topdown L1 metrics for neoverse-n2
From: John Garry <john.g.garry@oracle.com>
Date: 2022-11-21 17:56:40
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linux-perf-users, lkml
On 21/11/2022 15:17, Jing Zhang wrote:
quoted hunk ↗ jump to hunk
I'm sorry that I misunderstood the purpose of putting metric as arch_std_event at first, and now it works after the modification over your suggestion. But there are also a few questions: 1. The value of the slot in the topdownL1 is various in different architectures, for example, the slot is 5 on neoverse-n2. If I put topdownL1 metric as arch_std_event, then I need to specify the slot to 5 in n2. I can specify slot values in metric like below, but is there any other concise way to do this?diff --git a/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json index 8ff1dfe..b473baf 100644 --- a/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json +++ b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json@@ -1,4 +1,23 @@[ + { + "MetricExpr": "5", + "PublicDescription": "A pipeline slot represents the hardware resources needed to process one uOp", + "BriefDescription": "A pipeline slot represents the hardware resources needed to process one uOp", + "MetricName": "slot"
Ehhh....I'm not sure if that is a good idea. Ian or anyone else have an opinion on this? It is possible to reuse metrics, so it should work, but... One problem is that "slot" would show up as a metric, which you would not want. Alternatively I was going to suggest that you can overwrite specific std arch event attributes. So for example of frontend_bound, you could have: + b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json
@@ -0,0 +1,30 @@[
{
"ArchStdEvent": "FRONTEND_BOUND",
"MetricExpr": "(stall_slot_frontend - cpu_cycles) / (5 *
cpu_cycles)",
},
+ }
+ {
+ "ArchStdEvent": "FRONTEND_BOUND"
+ },
+ {
+ "ArchStdEvent": "BACKEND_BOUND"
+ },
+ {
+ "ArchStdEvent": "WASTED"
+ },
+ {
+ "ArchStdEvent": "RETIRING"
+ },
2. Should I add the topdownL1 metric to tools/perf/pmu-event/recommended.json,
or create a new json file to place the general metric?It would not belong in recommended.json as that is specifically for arch-recommended events. It would really just depend on where the value comes from, i.e. arm arm or sbsa.
Looking forward to your reply.
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