From: Jeff Dike <jdike@addtoit.com>
To: Hrishikesh <hrishikesh.amur@gmail.com>
Cc: user-mode-linux-devel@lists.sourceforge.net
Subject: Re: [uml-devel] Dramatic drop in C3 state residency with NO_HZ patches
Date: Tue, 6 Nov 2007 13:02:30 -0500 [thread overview]
Message-ID: <20071106180230.GA13370@c2.user-mode-linux.org> (raw)
In-Reply-To: <1f154f440710171243x40898f8bq386c91c59789fb42@mail.gmail.com>
On Wed, Oct 17, 2007 at 03:43:01PM -0400, Hrishikesh wrote:
> for the case where the kernel is patched, but NO_HZ is __not__ enabled,
> there is a do_nanosleep() every 100 or so us.
>
> setitimer(ITIMER_VIRTUAL, {it_interval={0, 0}, it_value={0, 0}},
> {it_interval={0, 0}, it_value={0, 0}}) = 0
> nanosleep({0, 0}, {0, 0}) = 0
Can you reproduce this with current mainline? I can't:
1194371604.120203 setitimer(ITIMER_VIRTUAL, {it_interval={0, 0}, it_value={0, 10000}}, NULL) = 0
1194371604.120256 setitimer(ITIMER_VIRTUAL, {it_interval={0, 0}, it_value={0, 0}}, {it_interval={0, 0}, it_value={0, 11998}}) = 0
1194371604.120306 nanosleep({0, 11998000}, {0, 11998000}) = 0
It's correctly reading the current alarm and sleeping for that long.
It could be more efficient, but this isn't a busy loop.
Jeff
--
Work email - jdike at linux dot intel dot com
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prev parent reply other threads:[~2007-11-06 18:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-17 2:36 [uml-devel] Dramatic drop in C3 state residency with NO_HZ patches Hrishikesh
2007-10-17 15:55 ` Jeff Dike
2007-10-17 16:16 ` Hrishikesh
2007-10-17 17:19 ` Jeff Dike
2007-10-17 19:43 ` Hrishikesh
2007-10-17 20:45 ` Jeff Dike
2007-10-17 23:29 ` Hrishikesh
2007-10-18 20:04 ` Jeff Dike
2007-10-23 19:21 ` Hrishikesh
2007-10-23 21:35 ` Jeff Dike
2007-10-23 23:53 ` Hrishikesh
2007-10-18 8:06 ` Hrishikesh
2007-11-06 18:02 ` Jeff Dike [this message]
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