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Date:   Sun, 11 Oct 2020 06:04:20 -0500
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     Mark Wielaard <mark@klomp.org>
Cc:     Andi Kleen <andi@firstfloor.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Stephane Eranian <eranian@google.com>,
        linux-toolchains@vger.kernel.org,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        "Phillips, Kim" <kim.phillips@amd.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: Additional debug info to aid cacheline analysis
Message-ID: <20201011110420.GO2672@gate.crashing.org>
References: <20201006131703.GR2628@hirez.programming.kicks-ass.net> <CABPqkBSkdqXjm6QuF9j6AO8MUnt1yZ_cA2PV=Qo8e4wKmK_6Ug@mail.gmail.com> <20201008070231.GS2628@hirez.programming.kicks-ass.net> <50338de81b34031db8637337f08b89b588476211.camel@klomp.org> <20201008212259.gdhlwdswn5pu4zos@two.firstfloor.org> <20201010205836.GA2666@wildebeest.org>
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Hi!

On Sat, Oct 10, 2020 at 10:58:36PM +0200, Mark Wielaard wrote:
> On Thu, Oct 08, 2020 at 02:23:00PM -0700, Andi Kleen wrote:
> > So I guess could disable it for 5.0+ only. 
> 
> 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.

Fwiw, GCC 4.10 was renamed to GCC 5 before it was released (it was the
first release with the new version number scheme).  Only old development
versions (that no one should use) identify as 4.10.

> And various distros would probably have backported the
> fix. But checking for 5.0+ would certainly give you a good version.

Yes, esp. since some versions of 4.9 and 4.8 are still buggy.  No one
should use any version for which a newer bug-fix release has long been
available, but do you want to deal with bugs from people who do not?


Segher