linux-kernel - Re: [PATCH RFC] [X86] performance improvement for memcpy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 09 Nov 2009 10:26:14 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	"Ma, Ling" <ling.ma@...el.com>, Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RFC] [X86] performance improvement for memcpy_64.S by fast string.

"H. Peter Anvin" <hpa@...or.com> writes:
>
> My personal opinion is that if we can show no significant slowdown on
> P4, K8, P-M/Core 1, Core 2, and Nehalem then we can simply use this code

The issue is Core 2.

P4 uses a different path, and Core 1 doesn't use the 64bit code.

> unconditionally.  If one of them is radically worse than baseline, then
> we have to do something conditional, which is a lot more complicated.

I have an older patchkit which did this, and some more optimizations
to this code.

There was still one open issue, that is why I didn't post it. If there's
interest I can post it.

-Andi
-- 
ak@...ux.intel.com -- Speaking for myself only.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/