linux-kernel - Re: [PATCH] x86: Run checksumming in parallel accross multiple alu's

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Message-ID: <20131101160802.GB8467@hmsreliant.think-freely.org>
Date:	Fri, 1 Nov 2013 12:08:02 -0400
From:	Neil Horman <nhorman@...driver.com>
To:	Ben Hutchings <bhutchings@...arflare.com>
Cc:	Doug Ledford <dledford@...hat.com>, Ingo Molnar <mingo@...nel.org>,
	Eric Dumazet <eric.dumazet@...il.com>,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	David Laight <David.Laight@...LAB.COM>
Subject: Re: [PATCH] x86: Run checksumming in parallel accross multiple alu's

On Fri, Nov 01, 2013 at 03:42:46PM +0000, Ben Hutchings wrote:
> On Thu, 2013-10-31 at 14:30 -0400, Neil Horman wrote:
> [...]
> > It
> > functions, but unfortunately the performance lost to the completely broken
> > branch prediction that this inflicts makes it a non starter:
> [...]
> 
> Conditional branches are no good but conditional moves might be worth a shot.
> 
> Ben.
> 
How would you suggest replacing the jumps in this case?  I agree it would be
faster here, but I'm not sure how I would implement an increment using a single
conditional move.
Neil

> -- 
> Ben Hutchings, Staff Engineer, Solarflare
> Not speaking for my employer; that's the marketing department's job.
> They asked us to note that Solarflare product names are trademarked.
> 
> 
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