From: Andi Kleen <ak@suse.de>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Benjamin LaHaise <bcrl@kvack.org>,
Zachary Amsden <zach@vmware.com>,
Chuck Ebbert <76306.1226@compuserve.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [rfc patch] i386: don't save eflags on task switch
Date: Sun, 5 Nov 2006 06:41:14 +0100 [thread overview]
Message-ID: <200611050641.14724.ak@suse.de> (raw)
In-Reply-To: <Pine.LNX.4.64.0611041959260.25218@g5.osdl.org>
> For me, when compiled with -O2, it results in
>
> 84
> 88
> 132
>
> which basically says: a "rdtsc->rdtsc" is 84 cycles, putting a "pushfl" in
> between is another _4_ cycles, and putting a "popfl" in between is about
> another 48 cycles.
This means we should definitely change restore_flags() to only STI,
never popf
-Andi
next prev parent reply other threads:[~2006-11-05 5:41 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-04 6:56 [rfc patch] i386: don't save eflags on task switch Chuck Ebbert
2006-11-04 19:09 ` Zachary Amsden
2006-11-04 19:35 ` Linus Torvalds
2006-11-05 3:55 ` Benjamin LaHaise
2006-11-05 4:13 ` Linus Torvalds
2006-11-05 5:41 ` Andi Kleen [this message]
2006-11-05 8:01 ` Zachary Amsden
2006-11-05 17:01 ` Andi Kleen
2006-11-05 17:26 ` Linus Torvalds
2006-11-05 17:34 ` Arjan van de Ven
2006-11-05 17:51 ` Linus Torvalds
2006-11-05 22:48 ` Zachary Amsden
2006-11-05 18:52 ` Andi Kleen
2006-11-05 16:12 ` Linus Torvalds
2006-11-05 16:54 ` Andi Kleen
2006-11-05 17:20 ` Linus Torvalds
2006-11-05 4:17 ` Zachary Amsden
2006-11-05 20:10 ` H. Peter Anvin
-- strict thread matches above, loose matches on Subject: below --
2006-11-04 0:00 Chuck Ebbert
2006-11-04 0:46 ` Linus Torvalds
2006-11-04 1:36 ` Andi Kleen
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