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Date:   Mon, 4 Jul 2022 16:03:00 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Fangrui Song <maskray@google.com>
Cc:     Bill Wendling <morbo@google.com>,
        "Jose E. Marchesi" <jemarch@gnu.org>,
        Ruud van der Pas <ruud.vanderpas@oracle.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Sami Tolvanen <samitolvanen@google.com>,
        Vladimir Mezentsev <vladimir.mezentsev@oracle.com>,
        clang-built-linux <llvm@lists.linux.dev>,
        LKML <linux-kernel@vger.kernel.org>, Yonghong Song <yhs@fb.com>,
        Wenlei He <wenlei@fb.com>, Hongtao Yu <hoy@fb.com>,
        Ingo Molnar <mingo@kernel.org>,
        linux-toolchains <linux-toolchains@vger.kernel.org>,
        elena.zannoni@oracle.com
Subject: Re: plumbers session on profiling?
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On Fri, Jul 01, 2022 at 12:34:09PM -0700, Fangrui Song wrote:

> Instrumentation based PGO has the nice property that it works with all
> architectures (the compiler supports) and does not rely on hardware
> support. In addition, it collects indirect call targets and string
> operation sizes which are very difficult/impossible for sample based
> PGO.

LBR samples should provide the indirect call targets just fine.