From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: melwyn lobo <linux.melwyn@gmail.com>
Cc: Maarten Lankhorst <m.b.lankhorst@gmail.com>,
Borislav Petkov <bp@amd64.org>,
"Valdis.Kletnieks@vt.edu" <Valdis.Kletnieks@vt.edu>,
Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@elte.hu>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: x86 memcpy performance
Date: Mon, 5 Dec 2011 14:36:08 +0000 [thread overview]
Message-ID: <20111205143608.76f3781a@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <CAHSGOuvJsJr3r+RwM0+733BQJO6hsK0iP0ZNzRoycWX3YHwE0A@mail.gmail.com>
> Will AVX work on Intel ATOM. I guess not. Then is this now not the
> time for having architecture dependant definitions for basic cpu
> intensive tasks
It's pretty much a necessity if you want to fine tune some of this.
> > If you want to speed up memcpy, I think your best bet is to find out why it's
> > so much slower when src and dst aren't 64-byte aligned compared to each other.
rep mov on most x86 processors is an extremely optimised path. The 64
byte alignment behaviour is to be expected given the processor cache line
size.
Alan
next prev parent reply other threads:[~2011-12-05 14:35 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-12 17:59 melwyn lobo
2011-08-12 18:33 ` Andi Kleen
2011-08-12 19:52 ` Ingo Molnar
2011-08-14 9:59 ` Borislav Petkov
2011-08-14 11:13 ` Denys Vlasenko
2011-08-14 12:40 ` Borislav Petkov
2011-08-15 13:27 ` melwyn lobo
2011-08-15 13:44 ` Denys Vlasenko
2011-08-16 2:34 ` Valdis.Kletnieks
2011-08-16 12:16 ` Borislav Petkov
2011-09-01 15:15 ` Maarten Lankhorst
2011-09-01 16:18 ` Linus Torvalds
2011-09-08 8:35 ` Borislav Petkov
2011-09-08 10:58 ` Maarten Lankhorst
2011-09-09 8:14 ` Borislav Petkov
2011-09-09 10:12 ` Maarten Lankhorst
2011-09-09 11:23 ` Maarten Lankhorst
2011-09-09 13:42 ` Borislav Petkov
2011-09-09 14:39 ` Linus Torvalds
2011-09-09 15:35 ` Borislav Petkov
2011-12-05 12:20 ` melwyn lobo
2011-12-05 12:54 ` melwyn lobo
2011-12-05 14:36 ` Alan Cox [this message]
2011-08-15 14:55 Borislav Petkov
2011-08-15 14:59 ` Andy Lutomirski
2011-08-15 15:29 ` Borislav Petkov
2011-08-15 15:36 ` Andrew Lutomirski
2011-08-15 16:12 ` Borislav Petkov
2011-08-15 17:04 ` Andrew Lutomirski
2011-08-15 18:49 ` Borislav Petkov
2011-08-15 19:11 ` Andrew Lutomirski
2011-08-15 20:05 ` Borislav Petkov
2011-08-15 20:08 ` Andrew Lutomirski
2011-08-15 16:12 ` H. Peter Anvin
2011-08-15 16:58 ` Andrew Lutomirski
2011-08-15 18:26 ` H. Peter Anvin
2011-08-15 18:35 ` Andrew Lutomirski
2011-08-15 18:52 ` H. Peter Anvin
2011-08-16 7:19 ` melwyn lobo
2011-08-16 7:43 ` Borislav Petkov
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