From: "H. Peter Anvin" <hpa@zytor.com>
To: linux-kernel@vger.kernel.org
Subject: Re: [BK+PATCH] remove __constant_memcpy
Date: 17 Apr 2003 17:29:23 -0700 [thread overview]
Message-ID: <b7ngt3$eln$1@cesium.transmeta.com> (raw)
In-Reply-To: Pine.LNX.4.44.0304171654530.14595-100000@home.transmeta.com
Followup to: <Pine.LNX.4.44.0304171654530.14595-100000@home.transmeta.com>
By author: Linus Torvalds <torvalds@transmeta.com>
In newsgroup: linux.dev.kernel
>
> > 2) why no sse2-optimized memcpy? just that noone has done one yet?
>
> Yes. If you want to, it's definitely the right thing to do. More so than
> the 3dnow stuff that is by now ancient. HOWEVER, I don't think there are
> any really valid large memcpy() calls inside the kernel. All the valid
> ones are either special-cased (ie "copy_page()") or to user space.
>
It's questionable, though, if SSE-2 buys you anything SSE-1 doesn't
already have. SSE-2 is basically integer and scalar ops for SSE, but
data moving and even XOR is perfectly well handled by SSE-1.
-hpa
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64
next prev parent reply other threads:[~2003-04-18 0:18 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-17 0:57 [BK+PATCH] remove __constant_memcpy Jeff Garzik
2003-04-17 1:04 ` Jeff Garzik
2003-04-17 2:06 ` Linus Torvalds
2003-04-17 8:46 ` Arjan van de Ven
2003-04-17 9:02 ` Roman Zippel
2003-04-17 9:04 ` Arjan van de Ven
2003-04-17 9:11 ` Jakub Jelinek
2003-04-17 16:07 ` Linus Torvalds
2003-04-17 19:07 ` Jeff Garzik
2003-04-17 19:19 ` Jeff Garzik
2003-04-17 19:54 ` Linus Torvalds
2003-04-17 23:49 ` Jeff Garzik
2003-04-17 23:52 ` Jeff Garzik
2003-04-17 23:59 ` Linus Torvalds
2003-04-18 0:29 ` H. Peter Anvin [this message]
2003-04-18 9:06 ` Arjan van de Ven
2003-04-18 14:31 ` Timothy Miller
2003-04-18 15:07 ` Richard B. Johnson
2003-04-17 22:58 ` J.A. Magallon
2003-04-17 23:10 ` Jeff Garzik
2003-04-17 13:17 ` Alan Cox
2003-04-17 13:17 ` Alan Cox
2003-04-17 14:32 ` Jeff Garzik
2003-04-17 14:40 ` Jeff Garzik
2003-04-17 20:01 ` H. Peter Anvin
-- strict thread matches above, loose matches on Subject: below --
2003-04-17 2:22 Nakajima, Jun
2003-04-17 23:50 Chuck Ebbert
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