mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>,
	linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@tglx.de
Subject: Re: [PATCH 4/5] select: make select() use schedule_hrtimeout()
Date: Fri, 29 Aug 2008 17:11:08 +0100	[thread overview]
Message-ID: <20080829171108.63e6dcd4@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <alpine.LFD.1.10.0808290915560.3300@nehalem.linux-foundation.org>

> "schedule_timeout()", there's a big difference between asking for two 
> ticks and asking for two seconds. The latter should probably try to round 
> to a nice timer tick basis for power reasons).

I disagree - that is fixing the problem in the wrong place. The timer
structure needs an accuracy field of some form that the existing timer
functions initialise to 0.

On a heavily loaded system with things like network events the behaviour
of the overall system is too complex to do the job well except at the
timer level which seems all. At the virtualisation level the hypervisor
needs to be doing the work to merge timer events between guests for power
management.

Once the timers have an accuracy representation there doesn't need to be
any real difference anywhere in the stack.

Alan

  reply	other threads:[~2008-08-29 16:28 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-29 15:05 [patch 0/5] Nano/Microsecond resolution for select() and poll() Arjan van de Ven
2008-08-29 15:06 ` [PATCH 1/5] select: add a timespec version of the timeout to select/poll Arjan van de Ven
2008-08-30  2:10   ` Andrew Morton
2008-08-30  2:54     ` Linus Torvalds
2008-08-29 15:07 ` [PATCH 2/5] select: return accurate remainer in select() and ppoll() Arjan van de Ven
2008-08-29 15:07 ` [PATCH 3/5] select: introduce a schedule_hrtimeout() function Arjan van de Ven
2008-08-29 15:08 ` [PATCH 4/5] select: make select() use schedule_hrtimeout() Arjan van de Ven
2008-08-29 15:36   ` Arnd Bergmann
2008-08-29 15:59   ` Daniel Walker
2008-08-29 16:20   ` Linus Torvalds
2008-08-29 16:11     ` Alan Cox [this message]
2008-08-29 17:26       ` Linus Torvalds
2008-08-29 17:42         ` Arjan van de Ven
2008-08-29 18:18         ` Alan Cox
2008-08-29 18:46           ` Linus Torvalds
2008-08-29 18:33             ` Alan Cox
2008-08-30 15:25               ` Arjan van de Ven
2008-08-29 16:30     ` Arjan van de Ven
2008-08-29 15:08 ` [PATCH 5/5] select: make poll() use schedule_hrtimeout() as well Arjan van de Ven
2008-08-29 15:54 ` [patch 0/5] Nano/Microsecond resolution for select() and poll() Arnd Bergmann
2008-08-29 16:12   ` Arjan van de Ven
2008-08-29 22:15 ` Brian Wellington

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20080829171108.63e6dcd4@lxorguk.ukuu.org.uk \
    --to=alan@lxorguk.ukuu.org.uk \
    --cc=arjan@infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=tglx@tglx.de \
    --cc=torvalds@linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®