linux-kernel - Re: Additional debug info to aid cacheline analysis

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Message-ID: <87h7r1x8kp.fsf@mid.deneb.enyo.de>
Date:   Sun, 11 Oct 2020 14:15:18 +0200
From:   Florian Weimer <fw@...eb.enyo.de>
To:     Mark Wielaard <mark@...mp.org>
Cc:     Andi Kleen <andi@...stfloor.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Stephane Eranian <eranian@...gle.com>,
        linux-toolchains@...r.kernel.org,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        "Phillips\, Kim" <kim.phillips@....com>,
        Mark Rutland <mark.rutland@....com>,
        Masami Hiramatsu <mhiramat@...nel.org>
Subject: Re: Additional debug info to aid cacheline analysis

* Mark Wielaard:

> Yes, that would work. I don't know what the lowest supported GCC
> version is, but technically it was definitely fixed in 4.10.0, 4.8.4
> and 4.9.2. And various distros would probably have backported the
> fix. But checking for 5.0+ would certainly give you a good version.
>
> How about the attached?

Would it be possible to test for the actual presence of the bug, using
-fcompare-debug?

(But it seems to me that the treatment of this particular compiler bug
is an outlier: other equally tricky bugs do not receive this kind of
attention.)