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From: Ingo Molnar <mingo@elte.hu>
To: Andrew Lutomirski <luto@mit.edu>
Cc: x86 <x86@kernel.org>,
	linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Arjan van de Ven <arjan@infradead.org>,
	Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH 3.1?] x86: Remove useless stts/clts pair in __switch_to
Date: Mon, 25 Jul 2011 16:13:39 +0200	[thread overview]
Message-ID: <20110725141339.GC3297@elte.hu> (raw)
In-Reply-To: <CAObL_7GTfH58gfgppg=KzKf8ztShA4LRFoZ0HyDXZ9M5Dii2BA@mail.gmail.com>


* Andrew Lutomirski <luto@mit.edu> wrote:

> > Also, if you are tempted by the prospect of possibly enabling 
> > vector instructions for the x86 kernel, we could try that too, 
> > and get multiple speedups for the price of having to debug the 
> > tree only once ;-)
> 
> I'll play with it.  I have some other cleanup / speedup ideas, too, 
> and I'll see where they go.  Given that the kernel doesn't really 
> use floating-point math, I'm not sure that gcc will do much unless 
> we turn on -ftree-vectorize, and that's a little scary.

It's indeed scary - but as long as it boots it would allow some 
baseline figures to be estimated - is there any win, and if yes, how 
much. It might be a complete dud in the end.

Thanks,

	Ingo

  reply	other threads:[~2011-07-25 14:14 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-24 21:07 [RFC] syscall calling convention, stts/clts, and xstate latency Andrew Lutomirski
2011-07-24 21:15 ` Ingo Molnar
2011-07-24 22:34   ` Andrew Lutomirski
2011-07-25  3:21     ` Andrew Lutomirski
2011-07-25  6:42       ` Ingo Molnar
2011-07-25 10:05       ` [PATCH 3.1?] x86: Remove useless stts/clts pair in __switch_to Andy Lutomirski
2011-07-25 11:12         ` Ingo Molnar
2011-07-25 13:04           ` Andrew Lutomirski
2011-07-25 14:13             ` Ingo Molnar [this message]
2011-07-25  6:38     ` [RFC] syscall calling convention, stts/clts, and xstate latency Ingo Molnar
2011-07-25  9:44       ` Andrew Lutomirski
2011-07-25  9:51         ` Ingo Molnar
2011-07-25 11:04         ` Hans Rosenfeld
2011-07-25  7:42   ` Avi Kivity
2011-07-25  7:54     ` Ingo Molnar

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