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From: Albert Cahalan <albert@users.sf.net>
To: Andi Kleen <ak@muc.de>
Cc: Albert Cahalan <albert@users.sourceforge.net>,
	linux-kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: get_current is __pure__, maybe __const__ even
Date: 16 Sep 2004 10:14:58 -0400	[thread overview]
Message-ID: <1095344098.3866.1396.camel@cube> (raw)
In-Reply-To: <m3llfaya29.fsf@averell.firstfloor.org>

On Thu, 2004-09-16 at 02:58, Andi Kleen wrote:
> Albert Cahalan <albert@users.sf.net> writes:
> 
> > Andi Kleen writes:
> >
> >> Please CSE "current" manually. It generates
> >> much better code on some architectures
> >> because the compiler cannot do it for you.
> >
> > This looks fixable.
> 
> I tried it some years ago, but I ran into problems with the scheduler
> and some other code and dropped it.

Right now, I'm thinking the switch_to assembly
has bad asm constraints.

I count 8 items passed in or out of the asm.
I count 11 clobbers. You don't have 19 registers.

If you pass something in and then destroy it,
you're supposed to use a dummy output. Look at
the i386 version, where esi and edi are dummy
outputs for this reason.

I recall seeing i386 compilers complain about
clobbered inputs. I guess the x86-64 gcc needs
to have this warning added?



  parent reply	other threads:[~2004-09-16 14:18 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <2ER4z-46B-17@gated-at.bofh.it>
2004-09-16  6:58 ` get_current is __pure__, maybe __const__ even Andi Kleen
2004-09-16 13:43   ` Albert Cahalan
2004-09-16 14:14   ` Albert Cahalan [this message]
2004-09-16 19:27     ` Andi Kleen
2004-09-15 22:50 Albert Cahalan
2004-09-15 23:15 ` Jakub Jelinek
2004-09-15 23:29   ` William Lee Irwin III
2004-09-16  2:10     ` Albert Cahalan
2004-09-16  2:36       ` William Lee Irwin III
2004-09-16  2:47         ` Nick Piggin
2004-09-16  3:23           ` William Lee Irwin III
2004-09-16  3:49         ` Albert Cahalan
2004-09-16  3:59           ` William Lee Irwin III
2004-09-16  9:04         ` Russell King
2004-09-16  9:11           ` Andi Kleen
2004-09-16  9:30             ` Russell King
2004-09-16 11:03               ` Andi Kleen
2004-09-16 14:36                 ` Russell King
2004-09-15 23:27 ` William Lee Irwin III

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