linux-kernel - Re: [REGRESSION][BISECT] perf/core: Remove pmu linear searching code

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Message-ID: <20230605092731.GZ4253@hirez.programming.kicks-ass.net>
Date:   Mon, 5 Jun 2023 11:27:31 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Mark Rutland <mark.rutland@....com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Ravi Bangoria <ravi.bangoria@....com>, jolsa@...nel.org,
        irogers@...gle.com, bp@...en8.de, adrian.hunter@...el.com,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "regressions@...ts.linux.dev" <regressions@...ts.linux.dev>
Subject: Re: [REGRESSION][BISECT] perf/core: Remove pmu linear searching code

On Mon, Jun 05, 2023 at 08:10:15AM +0100, Mark Rutland wrote:

> How does this work on x86? Do you have pseudo-PMUs for PERF_TYPE_HARDWARE and
> PERF_TYPE_RAW ?

Generic code maps TYPE_HARDWARE and TYPE_HW_CACHE to TYPE_RAW for a
first go, only if that fails it will try the actual type.

And x86 has the (first) CPU PMU has TYPE_RAW, on hybrid, it will
transparently pick the right actual PMU.

That said; given that this commit has been tagged twice now, I suppose I
should go revert it and we'll try again after a more thorough audit.