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From: "H. Peter Anvin" <hpa@zytor.com>
To: Andrew Lutomirski <luto@mit.edu>
Cc: Borislav Petkov <bp@alien8.de>,
	melwyn lobo <linux.melwyn@gmail.com>,
	Denys Vlasenko <vda.linux@googlemail.com>,
	Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	borislav.petkov@amd.com
Subject: Re: x86 memcpy performance
Date: Mon, 15 Aug 2011 11:26:57 -0700	[thread overview]
Message-ID: <4E4964F1.1020900@zytor.com> (raw)
In-Reply-To: <CAObL_7HAhSaknKRD=0BGWYdZaanX9fOc+i2B74K844T=1r6yGg@mail.gmail.com>

On 08/15/2011 09:58 AM, Andrew Lutomirski wrote:
> On Mon, Aug 15, 2011 at 12:12 PM, H. Peter Anvin <hpa@zytor.com> wrote:
>> On 08/15/2011 08:36 AM, Andrew Lutomirski wrote:
>>>
>>> (*)  kernel_fpu_begin is a bad name.  It's only safe to use integer
>>> instructions inside a kernel_fpu_begin section because MXCSR (and the
>>> 387 equivalent) could contain garbage.
>>>
>>
>> Uh... no, it just means you have to initialize the settings.  It's a
>> perfectly good name, it's called kernel_fpu_begin, not kernel_fp_begin.
> 
> I prefer get_xstate / put_xstate, but this could rapidly devolve into
> bikeshedding. :)
> 

a) Quite.

b) xstate is not architecture-neutral.

	-hpa


  reply	other threads:[~2011-08-15 18:28 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 [this message]
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
  -- strict thread matches above, loose matches on Subject: below --
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

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