From: Eric Northup <lkml@digitaleric.net>
To: Linus Torvalds <torvalds@transmeta.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Theurer <habanero@us.ibm.com>
Subject: Re: HT and idle = poll
Date: Thu, 6 Mar 2003 17:36:17 -0500 [thread overview]
Message-ID: <200303061736.17181.lkml@digitaleric.net> (raw)
In-Reply-To: <Pine.LNX.4.44.0303061206240.8404-100000@home.transmeta.com>
On Thursday 06 March 2003 03:08 pm, Linus Torvalds wrote:
> On 6 Mar 2003, Alan Cox wrote:
> > idle=poll probably needs to be doing "rep nop" in a tight loop.
>
> We already do that. It's not enough. The HT thing will still steal cycles
> continually, since the "rep nop" is really only equivalent to a
> "sched_yield()".
(Perhaps a naive idea) Right now, there is a single "rep nop" per poll. What
happens if you unroll the loop a few times:
while (!condition) {
cpu_relax();
cpu_relax();
cpu_relax();
}
? I have no HT hardware so can't test this.
-Eric
next prev parent reply other threads:[~2003-03-06 22:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-06 5:18 HT and idle = poll Andrew Theurer
2003-03-06 19:30 ` Linus Torvalds
2003-03-06 19:52 ` Davide Libenzi
2003-03-06 20:05 ` Linus Torvalds
2003-03-06 20:52 ` Davide Libenzi
2003-03-06 21:09 ` Alan Cox
2003-03-06 20:08 ` Linus Torvalds
2003-03-06 22:36 ` Eric Northup [this message]
2003-03-06 22:22 ` Martin J. Bligh
2003-03-06 23:59 ` John Levon
2003-03-06 21:15 Nakajima, Jun
2003-03-06 22:42 ` Alan Cox
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