linux-kernel - Re: [PATCH] x86: Use asm-goto to implement mutex fast path on x86-64

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Message-ID: <20130701145050.GI23515@pd.tnic>
Date:	Mon, 1 Jul 2013 16:50:50 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Wedson Almeida Filho <wedsonaf@...il.com>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
	linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH] x86: Use asm-goto to implement mutex fast path on x86-64

On Mon, Jul 01, 2013 at 07:45:41AM -0700, H. Peter Anvin wrote:
> Right... brain not awake yet, sorry, and responding from my phone.
> 
> I am not to worried about trading off a bit of additional branch mispredicts if everything else wins, but Ingo does have a valid question if we are measuring the right thing.
> 
> The effect is definitely big enough that it would be good to understand it one way or the other.
> 
> And regardless of the source... nice job!

Yeah, see my other reply. Ingo's way of tracing this doesn't show any
speedup. So I need to find out now why do I see the speedup the way I
run it.

Keep you posted.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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