Re: [PATCH v5 1/6] perf vendor events arm64: Add topdown L1 metrics for neoverse-n2

[John Garry <john.g.garry@oracle.com>]

On 03/01/2023 11:39, Jing Zhang wrote:
> The formula of topdown L1 on neoverse-n2 is from ARM sbsa7.0 platform
> design document [0], D37-38.

I think that I mentioned this before - if the these metrics are coming 
from an sbsa doc, then they are standard. As such, we can make them 
"arch std events" and put them in a common json such as sbsa.json, so 
that other cores may reuse.

You don't strictly have to do do this now, but it would be better.

Thanks,
John

> 
> However, due to the wrong count of stall_slot and stall_slot_frontend on
> neoverse-n2, the real stall_slot and real stall_slot_frontend need to
> subtract cpu_cycles,  so correct the expression of topdown metrics.
> Reference from ARM neoverse-n2 errata notice [1], D117.
> 
> Since neoverse-n2 does not yet support topdown L2, metricgroups such as
> Cache, TLB, Branch, InstructionsMix, and PEutilization will be added to
> further analysis of performance bottlenecks in the following patches.
> Reference from ARM PMU guide [2][3].