From: Ian Kumlien <pomac@vapor.com>
To: Robert Love <rml@tech9.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [SHED] Questions.
Date: Mon, 01 Sep 2003 00:41:25 +0200 [thread overview]
Message-ID: <1062369684.9959.166.camel@big.pomac.com> (raw)
In-Reply-To: <1062359478.1313.9.camel@boobies.awol.org>
[-- Attachment #1: Type: text/plain, Size: 2200 bytes --]
On Sun, 2003-08-31 at 21:51, Robert Love wrote:
> On Sun, 2003-08-31 at 15:31, Ian Kumlien wrote:
>
> > Since they would have a high pri still, and preempt is there... it
> > should be back on the cpu pretty quick.
>
> Ah, but no! You assume we do not have an expired list and round robin
> scheduling.
hummm, I assume that a high pri process can preempt a low pri process...
The rest sounds sane to me =), Please tell me what i'm missing.. =)
> Once a task exhausts its timeslice, it cannot run until all other tasks
> exhaust their timeslice. If this were not the case, high priority tasks
> could monopolize the system.
All other? including sleeping?... How many tasks can be assumed to run
on the cpu at a time?....
Should preempt send the new quantum value to all "low pri, high quantum"
processes?
Damn thats a tough cookie, i still think that the priority inversion is
bad. Don't know enough about this to actually provide a solution...
Any one else that has a view point?
> > But, it also creates problems for when a interactive process becomes a
> > cpu hog. Like this the detection should be faster, but should be slowed
> > down somewhat.
>
> I agree, although I do think it responds fairly quick. But, regardless,
> this is why I am interested in Nick's work. The interactivity estimator
> can never be perfect.
Hummm, the skips in xmms tells me that something is bad..
(esp since it works perfectly on the previus scheduler)
> > But, hogs would instead cause a context switch hell and lessen the
> > throughput on server loads...
>
> Hm, why?
Since it's rescheduled after a short runtime or, might be.
From someones mail i saw (afair), there was much more context switches
in 2.6 than in 2.4. And each schedule consumes time and cycles.
> > I don't see how priorities would be questioned... Since, all i say is
> > that a task that gets preempted should have a guaranteed time on the cpu
> > so that we don't waste cycles doing context switches all the time.
>
> But latency is important.
Oh yes, but otoh, if you are really keen on the latency then you'll do
realtime =)
--
Ian Kumlien <pomac@vapor.com>
[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 189 bytes --]
next prev parent reply other threads:[~2003-08-31 22:42 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-31 10:07 [SHED] Questions Ian Kumlien
2003-08-31 10:17 ` Nick Piggin
2003-08-31 10:24 ` Ian Kumlien
2003-08-31 10:41 ` Nick Piggin
2003-08-31 10:46 ` Nick Piggin
[not found] ` <1062326980.9959.65.camel@big.pomac.com>
[not found] ` <3F51D4A4.4090501@cyberone.com.au>
2003-08-31 11:08 ` Ian Kumlien
2003-08-31 11:31 ` Nick Piggin
2003-08-31 11:43 ` Ian Kumlien
2003-08-31 18:53 ` Robert Love
2003-08-31 19:31 ` Ian Kumlien
2003-08-31 19:51 ` Robert Love
2003-08-31 22:41 ` Ian Kumlien [this message]
2003-08-31 23:41 ` Robert Love
2003-09-01 0:00 ` Ian Kumlien
2003-09-01 2:50 ` Con Kolivas
2003-09-01 15:58 ` Antonio Vargas
2003-09-01 22:19 ` Ian Kumlien
2003-09-01 4:03 ` Robert Love
2003-09-01 5:07 ` Con Kolivas
2003-09-01 5:55 ` Robert Love
2003-09-01 22:24 ` Ian Kumlien
2003-09-01 14:21 ` Antonio Vargas
2003-09-01 19:36 ` Geert Uytterhoeven
2003-09-01 22:49 ` Ian Kumlien
2003-09-01 15:07 ` Daniel Phillips
2003-09-01 14:16 ` Antonio Vargas
2003-09-01 23:03 ` Ian Kumlien
2003-09-02 0:04 ` Nick Piggin
2003-09-02 0:23 ` Con Kolivas
2003-09-02 10:25 ` Ian Kumlien
2003-09-02 11:08 ` Nick Piggin
2003-09-02 17:22 ` Ian Kumlien
2003-09-02 23:49 ` Nick Piggin
2003-09-03 23:02 ` Ian Kumlien
2003-09-04 1:39 ` Mike Fedyk
2003-09-02 10:44 ` Wes Janzen
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=1062369684.9959.166.camel@big.pomac.com \
--to=pomac@vapor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rml@tech9.net \
/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;
as well as URLs for NNTP newsgroup(s).