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From: Andi Kleen <andi@firstfloor.org>
To: Hans Rosenfeld <hans.rosenfeld@amd.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	hpa@zytor.com, tglx@linutronix.de, mingo@elte.hu,
	suresh.b.siddha@intel.com, eranian@google.com, brgerst@gmail.com,
	robert.richter@amd.com, Andreas.Herrmann3@amd.com,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/9] rework of extended state handling, LWP support
Date: Wed, 30 Nov 2011 22:52:00 +0100	[thread overview]
Message-ID: <20111130215200.GS24062@one.firstfloor.org> (raw)
In-Reply-To: <20111130173745.GT878@escobedo.osrc.amd.com>

On Wed, Nov 30, 2011 at 06:37:46PM +0100, Hans Rosenfeld wrote:
> On Tue, Nov 29, 2011 at 01:31:09PM -0800, Andi Kleen wrote:
> > Hans Rosenfeld <hans.rosenfeld@amd.com> writes:
> > >
> > > The lazy allocation of the xstate area has been removed. The support for
> > > extended states that cannot be saved/restored lazily, like AMD's LWP,
> > > need this. Since optimized library functions using SSE etc. are widely
> > > used today, most processes would have an xstate area anyway, making the
> > > memory overhead negligible.
> > 
> > Do you have any data on that?  It sounds dubious for specialized
> > workloads.
> 
> What kind of specialized workload do you mean?

Anything that doesn't do large memcpys/memsets: glibc only uses SSE
when you pass large buffers. And then doesn't use the FPU. And possibly
has lots of processes.

Some older glibc did an unconditional FPU initialization at start,
but I believe that's long gone.

-Andi

  reply	other threads:[~2011-11-30 21:52 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-29 12:41 [PATCH 0/9] rework of extended state handling, LWP support Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 1/9] x86, xsave: warn on #NM exceptions caused by the kernel Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 2/9] x86, xsave: cleanup fpu/xsave support Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 3/9] x86, xsave: cleanup fpu/xsave signal frame setup Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 4/9] x86, xsave: rework fpu/xsave support Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 5/9] x86, xsave: remove unused code Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 6/9] x86, xsave: more cleanups Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 7/9] x86, xsave: remove lazy allocation of xstate area Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 8/9] x86, xsave: add support for non-lazy xstates Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 9/9] x86, xsave: add kernel support for AMDs Lightweight Profiling (LWP) Hans Rosenfeld
2011-11-29 21:31 ` [PATCH 0/9] rework of extended state handling, LWP support Andi Kleen
2011-11-30 17:37   ` Hans Rosenfeld
2011-11-30 21:52     ` Andi Kleen [this message]
2011-12-01 20:36       ` Hans Rosenfeld
2011-12-02  2:01         ` H. Peter Anvin
2011-12-02 11:20           ` Hans Rosenfeld
2011-12-07 19:57             ` Hans Rosenfeld
2011-12-07 20:00               ` [PATCH 7/8] x86, xsave: add support for non-lazy xstates Hans Rosenfeld
2011-12-07 20:00                 ` [PATCH 8/8] x86, xsave: add kernel support for AMDs Lightweight Profiling (LWP) Hans Rosenfeld
2011-12-05 10:22 ` [PATCH 0/9] rework of extended state handling, LWP support Ingo Molnar
2011-12-16 16:07   ` Hans Rosenfeld
2011-12-16 16:12     ` [RFC 1/5] x86, perf: Implement software-activation of lwp Hans Rosenfeld
2011-12-16 16:12       ` [RFC 2/5] perf: adds prototype for a new perf-context-type Hans Rosenfeld
2011-12-16 16:12       ` [RFC 3/5] perf: adds a new pmu-initialization-call Hans Rosenfeld
2011-12-16 16:12       ` [RFC 4/5] x86, perf: implements lwp-perf-integration (rc1) Hans Rosenfeld
2011-12-18  8:04         ` Ingo Molnar
2011-12-18 15:22           ` Benjamin Block
2011-12-18 23:43             ` Ingo Molnar
2011-12-19  9:09               ` Robert Richter
2011-12-19 10:54                 ` Ingo Molnar
2011-12-19 11:12                   ` Avi Kivity
2011-12-19 11:40                     ` Ingo Molnar
2011-12-19 11:58                       ` Avi Kivity
2011-12-19 18:13                         ` Benjamin
2011-12-20  8:56                           ` Ingo Molnar
2011-12-20  9:15                         ` Ingo Molnar
2011-12-20  9:47                           ` Avi Kivity
2011-12-20 10:09                             ` Ingo Molnar
2011-12-20 15:27                               ` Joerg Roedel
2011-12-20 18:40                                 ` Ingo Molnar
2011-12-21  0:07                                   ` Joerg Roedel
2011-12-21 12:34                                     ` Ingo Molnar
2011-12-21 12:44                                       ` Avi Kivity
2011-12-21 13:22                                         ` Ingo Molnar
2011-12-21 22:49                                           ` Joerg Roedel
2011-12-23 10:53                                             ` Ingo Molnar
2011-12-21 11:46                                   ` Gleb Natapov
2011-12-23 10:56                                     ` Ingo Molnar
2011-12-20 15:48                           ` Vince Weaver
2011-12-20 18:27                             ` Ingo Molnar
2011-12-20 22:47                               ` Vince Weaver
2011-12-21 12:00                                 ` Ingo Molnar
2011-12-21 13:55                                   ` Vince Weaver
2011-12-16 16:12       ` [RFC 5/5] x86, perf: adds support for the LWP threshold-int Hans Rosenfeld

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