From: David Laight <David.Laight@ACULAB.COM>
To: "'Li, Aubrey'" <aubrey.li@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Aubrey Li <aubrey.li@intel.com>
Cc: "mingo@redhat.com" <mingo@redhat.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"ak@linux.intel.com" <ak@linux.intel.com>,
"tim.c.chen@linux.intel.com" <tim.c.chen@linux.intel.com>,
"arjan@linux.intel.com" <arjan@linux.intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [RFC PATCH v2 1/2] x86/fpu: detect AVX task
Date: Tue, 13 Nov 2018 10:25:54 +0000 [thread overview]
Message-ID: <25dd33ee964f4de5ae33a1575e1bf47f@AcuMS.aculab.com> (raw)
In-Reply-To: <657a9ee9-bb27-968a-34ae-e25df6c2fff9@linux.intel.com>
From: Li, Aubrey
> Sent: 12 November 2018 01:41
...
> VZEROUPPER instruction resets the init state. If context switch happens
> to occur exactly after VZEROUPPER instruction, XINUSE bitmap is empty(all
> zeros), which indicates the task is not using AVX. That's why the state
> decay count is used here.
Isn't there an obvious optimisation to execute VZEROALL during system call
entry?
If that is done does any of this actually work?
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2018-11-13 10:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-07 17:16 [RFC PATCH v2 1/2] x86/fpu: detect AVX task Aubrey Li
2018-11-07 17:16 ` [RFC PATCH v2 2/2] proc: add /proc/<pid>/thread_state Aubrey Li
2018-11-09 11:21 ` [RFC PATCH v2 1/2] x86/fpu: detect AVX task Thomas Gleixner
2018-11-12 1:40 ` Li, Aubrey
2018-11-13 10:25 ` David Laight [this message]
2018-11-13 13:06 ` Li, Aubrey
2018-11-13 14:56 ` David Laight
2018-11-12 2:32 ` Dave Hansen
2018-11-12 5:38 ` Li, Aubrey
2018-11-12 15:46 ` Dave Hansen
2018-11-13 6:42 ` Li, Aubrey
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