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Date: Wed, 11 May 2016 14:47:56 +0200
From: Borislav Petkov <bp@suse.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Brian Gerst <brgerst@gmail.com>, "H. Peter Anvin" <hpa@zytor.com>,
        x86-ml <x86@kernel.org>, Denys Vlasenko <dvlasenk@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Dmitry Vyukov <dvyukov@google.com>, Andi Kleen <andi@firstfloor.org>,
        zengzhaoxiu@163.com, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>,
        Andy Lutomirski <luto@amacapital.net>
Subject: Re: [PATCH -v2] x86/hweight: Get rid of the special calling
 convention
Message-ID: <20160511124756.GG2180@pd.tnic>
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On Wed, May 11, 2016 at 01:24:09PM +0200, Peter Zijlstra wrote:
> Yeah, it might save a few cycles on the call, but given that most
> machines should have popcnt these days is it worth the hassle/cost of
> duplicating the lib/hweight.c magic in asm (and remember, twice, once
> for 32bit and once for 64bit) ?

Makes sense to me - we can do the funky cool stuff but considering the
fact that we have all the required bits already, I think we should do
the thunking game and be done with it.

I guess we're older, lazy and more realists now...

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--