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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230605093400.GK38236@hirez.programming.kicks-ass.net>
Date:   Mon, 5 Jun 2023 11:34:00 +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 11:27:31AM +0200, Peter Zijlstra wrote:
> 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.

Oh, I might've misread that last bit.. TYPE_RAW is always the big core,
it will not magic the thing. If you want little events you gotta
manually find the little pmu.