linux-kernel - Re: [PATCH v3] x86/vdso: Handle clock_gettime(CLOCK

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Message-ID: <0a94774a-6b8b-2014-93e6-131af9c319a6@redhat.com>
Date:   Sat, 1 Sep 2018 11:33:38 +0200
From:   Florian Weimer <fweimer@...hat.com>
To:     Andy Lutomirski <luto@...nel.org>,
        Matt Rickard <matt@...trans.com.au>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Stephen Boyd <sboyd@...nel.org>,
        John Stultz <john.stultz@...aro.org>, X86 ML <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] x86/vdso: Handle clock_gettime(CLOCK_TAI) in vDSO

On 09/01/2018 05:39 AM, Andy Lutomirski wrote:
> Florian, do you think
> glibc would be willing to add some magic to turn
> clock_gettime(CLOCK_MONOTONIC, t) into
> __vdso_clock_gettime_monotonic(t) when CLOCK_MONOTONIC is a constant?

What's the goal here?  Turn the indirect call/conditional jump/indirect 
call sequence into a single indirect call, purely for performance reasons?

Thanks,
Florian