From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: "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: Mon, 09 Nov 2009 08:41:36 -0800 [thread overview]
Message-ID: <4AF84640.7010705@zytor.com> (raw)
In-Reply-To: <87ws2059s9.fsf@basil.nowhere.org>
On 11/09/2009 01:26 AM, Andi Kleen wrote:
> "H. Peter Anvin" <hpa@zytor.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.
>
Ling's numbers didn't seem to show a significant slowdown on Core 2 (it
was something like 0.95x baseline in the worst case, and most of the
cases were positive) so Core 2 doesn't seem to have a problem.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2009-11-09 16:41 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
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 [this message]
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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