From: Avi Kivity <avi@argo.co.il>
To: Andreas Mohr <andi@rhlx01.fht-esslingen.de>
Cc: Chuck Ebbert <76306.1226@compuserve.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Emmanuel Fleury <emmanuel.fleury@labri.fr>,
Linus Torvalds <torvalds@osdl.org>
Subject: Re: [patch] i386: use C code for current_thread_info()
Date: Tue, 13 Jun 2006 12:27:10 +0300 [thread overview]
Message-ID: <448E84EE.9000503@argo.co.il> (raw)
In-Reply-To: <20060613064311.GA27543@rhlx01.fht-esslingen.de>
Andreas Mohr wrote:
>
> An entirely different way would be to store the stack base value in a
> global variable and update that on each context switch, but it would
> increase
> context switch overhead and have >= 2 cycles access time for L1 cache
> (which
> would be the best memory access case!), which would most likely be more
> combined overhead than an AGI stall (I was mistaken in declaring the
> stall
> a pipeline flush - it's only a stall for a couple cycles, not a full
> flush
> wasting ~ 15 cycles).
>
That wouldn't work on SMP. You'd need per-cpu variables, which are
likely even slower.
[One way around that would be to use a segment register for the per-cpu
areas]
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2006-06-13 9:27 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-13 1:50 [patch] i386: use C code for current_thread_info() Chuck Ebbert
2006-06-13 6:43 ` Andreas Mohr
2006-06-13 9:27 ` Avi Kivity [this message]
-- strict thread matches above, loose matches on Subject: below --
2006-06-13 5:26 Albert Cahalan
2006-06-12 17:14 Chuck Ebbert
2006-06-12 17:55 ` Adrian Bunk
2006-06-12 18:48 ` Andreas Mohr
2006-06-11 20:43 Chuck Ebbert
2006-06-11 21:05 ` Emmanuel Fleury
2006-06-11 19:07 Chuck Ebbert
2006-06-11 19:33 ` Linus Torvalds
2006-06-11 19:42 ` Jan Engelhardt
2006-06-11 20:33 ` Jan Engelhardt
2006-06-11 20:44 ` Alistair John Strachan
2006-06-12 8:10 ` Andi Kleen
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