From: Pavel Machek <pavel@ucw.cz>
To: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>, "Ma, Ling" <ling.ma@intel.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC] [X86] performance improvement for memcpy_64.S by fast string.
Date: Thu, 12 Nov 2009 13:16:19 +0100 [thread overview]
Message-ID: <20091112121619.GD1394@ucw.cz> (raw)
In-Reply-To: <20091109080830.GI453@elte.hu>
> Ling, if you are interested, could you send a user-space test-app to
> this thread that everyone could just compile and run on various older
> boxes, to gather a performance profile of hand-coded versus string ops
> performance?
>
> ( And i think we can make a judgement based on cache-hot performance
> alone - if then the strings ops will perform comparatively better in
> cache-cold scenarios, so the cache-hot numbers would be a conservative
> estimate. )
Ugh, really? I'd expect cache-cold performance to be not helped at all
(memory bandwidth limit) and you'll get slow down from additional
i-cache misses...
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2009-11-12 23:04 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-06 9:41 [PATCH RFC] [X86] performance improvement for memcpy_64.S by fast string ling.ma
2009-11-06 16:51 ` Andi Kleen
2009-11-08 10:18 ` Ingo Molnar
2009-11-06 17:07 ` H. Peter Anvin
2009-11-06 19:26 ` H. Peter Anvin
2009-11-09 7:24 ` Ma, Ling
2009-11-09 7:36 ` H. Peter Anvin
2009-11-09 8:08 ` Ingo Molnar
2009-11-11 7:05 ` Ma, Ling
2009-11-11 7:18 ` Ingo Molnar
2009-11-11 7:57 ` Ma, Ling
2009-11-11 23:21 ` H. Peter Anvin
2009-11-12 2:12 ` Ma, Ling
2009-11-11 20:34 ` Cyrill Gorcunov
2009-11-11 22:39 ` H. Peter Anvin
2009-11-12 4:28 ` Cyrill Gorcunov
2009-11-12 4:49 ` Ma, Ling
2009-11-12 5:26 ` H. Peter Anvin
2009-11-12 7:42 ` Ma, Ling
2009-11-12 9:54 ` Cyrill Gorcunov
2009-11-12 12:16 ` Pavel Machek [this message]
2009-11-13 7:33 ` Ingo Molnar
2009-11-13 8:04 ` H. Peter Anvin
2009-11-13 8:10 ` Ingo Molnar
2009-11-09 9:26 ` Andi Kleen
2009-11-09 16:41 ` H. Peter Anvin
2009-11-09 18:54 ` Andi Kleen
2009-11-09 22:36 ` H. Peter Anvin
2009-11-12 12:16 ` Pavel Machek
2009-11-13 5:33 ` Ma, Ling
2009-11-13 6:04 ` H. Peter Anvin
2009-11-13 7:23 ` Ma, Ling
2009-11-13 7:30 ` H. Peter Anvin
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