From: "Jan Beulich" <JBeulich@suse.com>
To: "Andi Kleen" <andi@firstfloor.org>, "H. Peter Anvin" <hpa@zytor.com>
Cc: <mingo@elte.hu>, <tglx@linutronix.de>, <linux-kernel@vger.kernel.org>
Subject: Re: x86-64: memset()/memcpy() not fully standards compliant
Date: Fri, 06 Jan 2012 07:22:34 +0000 [thread overview]
Message-ID: <4F06AF4A020000780006AC14@nat28.tlf.novell.com> (raw)
In-Reply-To: <4F06566B.8080708@zytor.com>
>>> On 06.01.12 at 03:03, "H. Peter Anvin" <hpa@zytor.com> wrote:
> On 01/05/2012 05:47 PM, Andi Kleen wrote:
>>>
>>> Is that still true, and do we even use string instructions still on
>>> those old CPUs? Jan's fixes don't introduce any additional delays in
>>> the non-string-instruction paths.
>>
>> Yes various of the CPUs with bugs used string instructions.
>>
>
> Which CPUs are you talking about here?
Indeed, I went through various specification updates/revision guides
without finding any relevant erratum.
>>
>> Both string and non string instructions are used on modern CPUs,
>> so making any of that slower is not a good idea.
>>
>
> Obviously not, but I'm perfectly fine turning REP_GOOD off on old broken
> CPUs.
Yes, that's what my plan would have been too, had I been able to
identify any specific CPU(s) that actually suffer from such problems.
Jan
next prev parent reply other threads:[~2012-01-06 10:21 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-05 14:04 Jan Beulich
2012-01-05 15:27 ` hpanvin@gmail.com
2012-01-05 18:28 ` Andi Kleen
2012-01-05 23:22 ` H. Peter Anvin
2012-01-06 1:47 ` Andi Kleen
2012-01-06 2:03 ` H. Peter Anvin
2012-01-06 7:22 ` Jan Beulich [this message]
2012-01-06 9:49 ` Andi Kleen
2012-01-06 10:22 ` Jan Beulich
2012-01-06 10:37 ` Andi Kleen
2012-01-06 10:50 ` Jan Beulich
2012-01-06 11:08 ` Andi Kleen
2012-01-06 12:25 ` Jan Beulich
2012-01-06 19:44 ` Andi Kleen
2012-01-06 23:12 ` H. Peter Anvin
2012-01-06 11:08 ` Ingo Molnar
2012-01-06 20:40 ` Valdis.Kletnieks
2012-01-09 8:29 ` Jan Beulich
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