linux-kernel - Re: [PATCH v7 00/13] perf/x86/amd: Add AMD Fam19h Branch Sampling support

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Date:   Wed, 30 Mar 2022 13:01:51 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Stephane Eranian <eranian@...gle.com>
Cc:     linux-kernel@...r.kernel.org, kim.phillips@....com,
        acme@...hat.com, jolsa@...hat.com, songliubraving@...com,
        rafael@...nel.org, ravi.bangoria@....com, Sandipan.Das@....com
Subject: Re: [PATCH v7 00/13] perf/x86/amd: Add AMD Fam19h Branch Sampling
 support

On Tue, Mar 29, 2022 at 04:47:52PM -0700, Stephane Eranian wrote:
> False alarm. I had not forced the config option. With the config
> option enabled, it works as expected.

Great!

> I just found a minor issue in case BRS is not enabled. To be
> consistent, we should do:
> 
> --- a/arch/x86/events/perf_event.h
> +++ b/arch/x86/events/perf_event.h
> @@ -1265,7 +1265,7 @@ static inline s64 amd_brs_adjust_period(s64 period)
>  #else
>  static inline int amd_brs_init(void)
>  {
> -       return 0;
> +       return -EOPNOTSUPP;
>  }

Done!