Re: [PATCH RFC] perf/x86/amd/lbr: Don't freeze the LBR on PMI for user-only filters

[Ravi Bangoria]

Puranjay, Andrii,

>> heh, so we basically either
>>
>> a) opt-in freeze with *new config*, but do it *only for non-kernel LBR*
>>
>> or
>>
>> b) opt-out freeze *only for non-kernel LBR* _unconditionally_, but
>> without adding any new config
>>
>> In both cases we have a behavior that makes sense in practice, but a)
>> adds some new config, while b) doesn't add anything. End result is the
>> same, just more configuration and need to change user space code to
>> opt-out the freeze.
>>
>> Is a) worth it, or we should stick to b) and keep it simple, Sandipan?

Have you run a PGO experiment with the patch, and does it show a
benefit? Also, have you seen any regression in any benchmarks? If
no-freeze regresses some of them, we may need to give the user an
option to keep the freeze enabled. No?

Thanks,
Ravi