From: "H. Peter Anvin" <hpa@zytor.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
the arch/x86 maintainers <x86@kernel.org>
Subject: Re: [GIT pull] x86 mpx support for 3.19
Date: Fri, 12 Dec 2014 08:40:29 -0800 [thread overview]
Message-ID: <548B1A7D.7040403@zytor.com> (raw)
In-Reply-To: <CA+55aFwzCuFCzASb4Kj1WC7S9v1wSKN2dHj_ns_1uy2GG6Svqw@mail.gmail.com>
On 12/10/2014 12:49 PM, Linus Torvalds wrote:
> On Wed, Dec 10, 2014 at 12:39 PM, Dave Hansen
> <dave.hansen@linux.intel.com> wrote:
>>
>> I misspoke there. I meant SMAP (I placed MPX below its config option).
>
> Ok, I agree on SMAP, we might want to have that be configurable too,
> especially for smaller systems (I *think* SMAP is big-core only,
> right?). I'm not sure how much of a possible performance downside it
> has, but it does add instructions to potentially critical areas.
>
*As far as I know*, SMAP will be pushed into all CPUs over time.
SMAP is already configurable, although the overhead on non-SMAP-enabled
hardware is minimal (the CLAC/STAC instructions get patched out.)
-hpa
next prev parent reply other threads:[~2014-12-12 16:40 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-09 14:08 Thomas Gleixner
2014-12-10 19:05 ` Linus Torvalds
2014-12-10 19:41 ` Dave Hansen
2014-12-10 19:49 ` Linus Torvalds
2014-12-10 20:39 ` Dave Hansen
2014-12-10 20:49 ` Linus Torvalds
2014-12-12 16:40 ` H. Peter Anvin [this message]
2014-12-11 6:19 ` Ingo Molnar
2014-12-11 22:02 ` Dave Hansen
2014-12-12 8:31 ` Ingo Molnar
2014-12-12 12:30 ` Pavel Machek
2014-12-12 15:47 ` Dave Hansen
2014-12-12 17:21 ` Pavel Machek
2014-12-10 19:49 ` Dave Hansen
2014-12-11 2:14 ` Eric W. Biederman
2014-12-11 2:30 ` Dave Hansen
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