From: Artur Skawina <art_k@o2.pl>
To: Xavier Bestel <xavier.bestel@free.fr>
Cc: Willy Tarreau <w@1wt.eu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Mark Lord <lkml@rtr.ca>, Al Boldi <a1426z@gawab.com>,
Mike Galbraith <efault@gmx.de>, Con Kolivas <kernel@kolivas.org>,
ck@vds.kolivas.org, Serge Belyshev <belyshev@depni.sinp.msu.ru>,
Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org, Nicholas Miell <nmiell@comcast.net>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: RSDL v0.31
Date: Tue, 20 Mar 2007 13:31:06 +0100 [thread overview]
Message-ID: <45FFD40A.1090104@o2.pl> (raw)
In-Reply-To: <1174381383.30876.86.camel@frg-rhel40-em64t-04>
Xavier Bestel wrote:
> On Tue, 2007-03-20 at 07:11 +0100, Willy Tarreau wrote:
>> I don't agree with starting to renice X to get something usable
>
> X looks very special to me: it's a big userspace driver, the primary
> task handling user interaction on the desktop, and on some OS the part
> responsible for moving the mouse pointer and interacting with windows is
> even implemented as an interrupt handler, and that for sure provides for
> smooth user experience even on very low-end hardware. Why not compensate
> for X design by prioritizing it a bit ?
> If RSDL + reniced X makes for a better desktop than sotck kernel + X, on
> all kind of workloads, it's good to know.
No, running X at a different priority than its clients is not really
a good idea. If it isn't immediately obvious why try something like
this:
mkdir /tmp/tempdir
cd /tmp/tempdir
for i in `seq -w 1 10000` ; do touch
longfilenamexxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx$i
; done
nice --20 xterm &
xterm &
nice -20 xterm &
then do "time ls -l ." in each xterm.
This is what i get on UP 2.6.20+RSDL.31 w/ X at nice 0:
-20: 0m0.244s user 0m0.156s system 0m3.113s elapsed 12.84% CPU
0: 0m0.216s user 0m0.168s system 0m2.801s elapsed 13.70% CPU
19: 0m0.188s user 0m0.196s system 0m3.268s elapsed 11.75% CPU
I just made this simple example up and it doesn't show the problem
too well, but you can already see the ~10% performance drop. It's
actually worse in practice, because for some apps the increased
amount of rendering is clearly visible; text areas scroll
line-by-line, content is incrementally redrawn several times etc.
This happens because an X server running at a higher priority than a
client will often get scheduled immediately after some x11 traffic
arrives; when the process priorities are equal usually the client
gets a chance to supply some more data. IOW by renicing the server
you make X almost synchronous.
This isn't specific to RSDL - it happens w/ any cpu scheduler; and
while the effects of less extreme prio differences (ie -5 instead of
-20 etc) may be less visible i also doubt they will help much.
A better approach to X interactivity might be allowing the server to
use (part of) the clients timeslice, but it's not trivial -- you'd
only want to do that when the client is waiting for a reply and you
almost never want to preempt the client just because the server
received some data.
As to RSDL - it seems to work great for desktop use and feels better
than mainline. However top output under 100% load (eg kernel
compilation) looks like below -- the %CPU error seems a bit high...
Tasks: 97 total, 6 running, 91 sleeping, 0 stopped, 0 zombie
Cpu(s): 81.7% us, 18.3% sy, 0.0% ni, 0.0% id, 0.0% wa, 0.0% hi,
0.0% si
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7566 root 17 0 9196 4108 1188 R 3.0 0.8 0:00.09 cc1
7499 root 11 0 1952 924 648 S 0.3 0.2 0:00.01 make
12279 root 1 0 5556 2928 2064 S 0.3 0.6 0:00.83 xterm
31510 root 1 0 2152 1100 840 R 0.3 0.2 0:00.25 top
1 root 1 0 1584 88 60 S 0.0 0.0 0:00.30 init
artur
next prev parent reply other threads:[~2007-03-20 12:38 UTC|newest]
Thread overview: 197+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-04 20:35 [ANNOUNCE] RSDL completely fair starvation free interactive cpu scheduler Al Boldi
2007-03-04 21:49 ` Con Kolivas
[not found] ` <45EB45F7.3050208@simon.arlott.org.uk>
2007-03-04 22:27 ` Con Kolivas
2007-03-05 18:29 ` Simon Arlott
2007-03-05 21:36 ` Con Kolivas
2007-03-04 23:13 ` Willy Tarreau
2007-03-04 23:58 ` Con Kolivas
2007-03-05 0:10 ` [ck] " jos poortvliet
2007-03-05 1:09 ` Gene Heskett
[not found] ` <200703050834.45712.a1426z@gawab.com>
[not found] ` <20070305060732.GQ30401@nysv.org>
2007-03-05 11:59 ` [ck] " Al Boldi
2007-03-05 12:29 ` Con Kolivas
[not found] ` <200703052123.01095.a1426z@gawab.com>
2007-03-05 22:10 ` Con Kolivas
2007-03-06 8:42 ` Xavier Bestel
2007-03-06 15:15 ` Al Boldi
2007-03-11 18:11 ` Al Boldi
2007-03-11 21:52 ` Con Kolivas
2007-03-11 22:12 ` Con Kolivas
2007-03-12 4:42 ` Al Boldi
2007-03-12 4:53 ` Con Kolivas
2007-03-12 11:26 ` Al Boldi
2007-03-12 12:52 ` Con Kolivas
2007-03-12 14:14 ` Al Boldi
2007-03-12 14:58 ` [ck] " jos poortvliet
2007-03-12 16:37 ` michael chang
2007-03-12 17:41 ` Al Boldi
2007-03-12 18:05 ` Con Kolivas
2007-03-12 18:47 ` [ck] " jos poortvliet
2007-03-12 18:58 ` Antonio Vargas
2007-03-19 10:47 ` Helge Hafting
2007-03-18 1:30 ` Bill Davidsen
2007-03-18 10:50 ` [ck] " jos poortvliet
2007-03-13 15:31 ` [PATCH] [RSDL-0.30] sched: rsdl improve latencies with differential nice Con Kolivas
2007-03-13 16:03 ` [PATCH] [RSDL-0.30] sched: rsdl improve latencies with differential nice -1 Con Kolivas
2007-03-13 16:08 ` Con Kolivas
2007-03-13 20:58 ` Con Kolivas
2007-03-13 23:08 ` RSDL development plans Con Kolivas
2007-03-16 12:25 ` Con Kolivas
2007-03-16 13:40 ` RSDL v0.31 Con Kolivas
2007-03-16 15:34 ` Mike Galbraith
2007-03-16 21:13 ` Con Kolivas
2007-03-16 22:30 ` Mike Galbraith
2007-03-16 23:05 ` [ck] " Dirk Schoebel
2007-03-17 4:24 ` Nicholas Miell
2007-03-17 5:56 ` Mike Galbraith
2007-03-17 6:08 ` Mike Galbraith
2007-03-17 13:56 ` Ed Tomlinson
2007-03-18 19:37 ` Lee Revell
2007-03-18 19:55 ` Mike Galbraith
2007-03-18 22:45 ` Szonyi Calin
2007-03-19 2:27 ` David Schwartz
2007-03-19 6:21 ` Mike Galbraith
2007-03-19 6:59 ` Willy Tarreau
2007-03-17 6:26 ` Nicholas Miell
2007-03-17 7:11 ` Mike Galbraith
2007-03-17 7:25 ` William Lee Irwin III
2007-03-17 7:29 ` Nicholas Miell
2007-03-17 11:48 ` Gene Heskett
2007-03-17 7:45 ` Ingo Molnar
2007-03-17 7:44 ` David Lang
2007-03-17 8:46 ` Mike Galbraith
2007-03-17 14:09 ` [ck] " Mark Glines
2007-03-17 14:33 ` Mike Galbraith
2007-03-17 14:54 ` Mark Glines
2007-03-17 14:58 ` Mike Galbraith
2007-03-17 8:23 ` Nicholas Miell
2007-03-17 9:42 ` [patch] CFS scheduler: Completely Fair Scheduler / CONFIG_SCHED_FAIR Ingo Molnar
2007-03-17 8:41 ` RSDL v0.31 Serge Belyshev
2007-03-17 9:48 ` Con Kolivas
2007-03-17 9:58 ` Mike Galbraith
2007-03-17 10:49 ` Mike Galbraith
2007-03-17 12:05 ` Gene Heskett
2007-03-17 13:36 ` Mike Galbraith
2007-03-17 17:03 ` Gene Heskett
2007-03-17 17:37 ` Mike Galbraith
2007-03-17 18:23 ` [ck] " Kacper Wysocki
2007-03-17 18:45 ` Mike Galbraith
2007-03-17 13:58 ` michael chang
2007-03-17 20:55 ` Al Boldi
2007-03-18 6:17 ` Mike Galbraith
2007-03-18 6:47 ` Kasper Sandberg
2007-03-18 7:08 ` Mike Galbraith
2007-03-18 7:22 ` [ck] " Radoslaw Szkodzinski
2007-03-18 7:38 ` Mike Galbraith
2007-03-18 8:04 ` Mike Galbraith
2007-03-18 8:20 ` jimmy bahuleyan
2007-03-18 8:34 ` Mike Galbraith
2007-03-18 9:57 ` Kasper Sandberg
2007-03-18 13:57 ` Avuton Olrich
2007-03-19 20:47 ` Bill Davidsen
2007-03-20 10:19 ` jos poortvliet
2007-03-21 8:58 ` Kasper Sandberg
2007-03-18 15:44 ` Radoslaw Szkodzinski
2007-03-18 16:09 ` jos poortvliet
2007-03-19 16:07 ` Mark Lord
2007-03-19 16:26 ` Xavier Bestel
2007-03-19 16:36 ` Mark Lord
2007-03-19 16:43 ` Xavier Bestel
2007-03-20 3:11 ` Linus Torvalds
2007-03-20 6:11 ` Willy Tarreau
2007-03-20 8:03 ` Mike Galbraith
2007-03-21 14:57 ` Mike Galbraith
2007-03-21 16:02 ` Peter Zijlstra
2007-03-21 17:06 ` Mike Galbraith
2007-03-22 7:07 ` Mike Galbraith
2007-03-22 9:18 ` Ingo Molnar
2007-03-22 9:34 ` Mike Galbraith
2007-03-22 9:41 ` Mike Galbraith
2007-03-22 22:03 ` Con Kolivas
2007-03-22 22:50 ` Con Kolivas
2007-03-23 4:39 ` Mike Galbraith
2007-03-23 5:59 ` Con Kolivas
2007-03-23 6:11 ` Mike Galbraith
2007-03-23 12:17 ` Mike Galbraith
[not found] ` <20070321161147.54c7a727@localhost>
2007-03-21 17:07 ` Mike Galbraith
2007-03-22 4:49 ` Willy Tarreau
2007-03-22 7:14 ` Mike Galbraith
2007-03-20 9:03 ` Xavier Bestel
2007-03-20 12:31 ` Artur Skawina [this message]
2007-03-20 19:16 ` Artur Skawina
2007-03-21 7:50 ` Ingo Molnar
2007-03-21 10:43 ` David Schwartz
2007-03-28 23:37 ` Bill Davidsen
2007-03-29 7:10 ` David Schwartz
2007-03-29 7:34 ` Nick Piggin
2007-03-20 15:31 ` Linus Torvalds
2007-03-20 18:08 ` Al Boldi
2007-03-21 8:22 ` Keith Duthie
2007-03-28 23:43 ` Bill Davidsen
2007-03-20 10:26 ` [ck] " jos poortvliet
2007-03-20 13:22 ` Mark Lord
2007-03-20 15:16 ` Ray Lee
2007-03-20 15:20 ` Mark Lord
2007-03-21 8:55 ` Kasper Sandberg
2007-03-19 20:53 ` Al Boldi
2007-03-20 19:50 ` Artur Skawina
2007-03-21 4:15 ` Al Boldi
2007-03-21 17:24 ` Artur Skawina
2007-03-19 16:03 ` Mark Lord
2007-03-17 11:49 ` is RSDL an "unfair" scheduler too? Ingo Molnar
2007-03-17 12:02 ` Con Kolivas
2007-03-17 12:23 ` [ck] " jos poortvliet
2007-03-17 17:31 ` David Schwartz
2007-03-17 12:28 ` Ingo Molnar
2007-03-17 12:43 ` Con Kolivas
2007-03-17 16:34 ` Ingo Molnar
2007-03-18 3:23 ` Bill Davidsen
2007-03-18 2:13 ` Bill Davidsen
2007-03-18 3:20 ` Kasper Sandberg
2007-03-18 5:37 ` Mike Galbraith
2007-03-18 10:58 ` [ck] " jos poortvliet
2007-03-17 12:15 ` jos poortvliet
2007-03-17 20:41 ` Avi Kivity
2007-03-18 1:25 ` William Lee Irwin III
2007-03-18 1:32 ` Linus Torvalds
2007-03-18 5:24 ` Willy Tarreau
2007-03-18 5:55 ` Avi Kivity
2007-03-19 2:27 ` David Schwartz
2007-03-19 13:27 ` Radoslaw Szkodzinski
2007-03-19 18:30 ` David Lang
2007-03-19 15:25 ` Avi Kivity
2007-03-19 16:06 ` Helge Hafting
2007-03-19 16:37 ` Avi Kivity
2007-03-18 6:09 ` Bill Huey
2007-03-18 6:37 ` Mike Galbraith
2007-03-18 7:35 ` Bill Huey
2007-03-19 21:14 ` Bill Davidsen
2007-03-18 6:26 ` Mike Galbraith
2007-03-18 6:54 ` [ck] " Radoslaw Szkodzinski
2007-03-18 7:58 ` Willy Tarreau
2007-03-18 8:45 ` Avi Kivity
2007-03-18 5:00 ` Avi Kivity
2007-03-17 15:13 ` RSDL v0.31 Mark Hahn
2007-03-17 17:22 ` Stephen Clark
2007-03-19 15:06 ` Chris Friesen
2007-03-17 7:56 ` Ingo Molnar
2007-03-17 11:07 ` [ck] " jos poortvliet
2007-03-17 12:44 ` Ingo Molnar
2007-03-17 13:44 ` jos poortvliet
2007-03-17 14:04 ` [ck] " Ed Tomlinson
2007-03-17 14:32 ` Rik van Riel
2007-03-17 14:43 ` Mike Galbraith
2007-03-17 15:39 ` Ingo Molnar
2007-03-16 17:12 ` AshMilsted
2007-03-16 17:41 ` Gabriel C
2007-03-16 21:55 ` Al Boldi
2007-03-17 2:51 ` Con Kolivas
2007-03-17 4:40 ` Al Boldi
2007-03-17 4:57 ` Con Kolivas
2007-03-17 5:15 ` Gene Heskett
2007-03-17 13:50 ` Ed Tomlinson
2007-03-17 16:12 ` Al Boldi
2007-03-16 13:42 ` RSDL development plans Mike Galbraith
2007-03-16 13:59 ` Con Kolivas
2007-03-16 14:07 ` Mike Galbraith
2007-03-14 9:13 ` [PATCH] [RSDL-0.30] sched: rsdl improve latencies with differential nice Mike Galbraith
2007-03-14 9:25 ` Con Kolivas
2007-03-14 9:42 ` Mike Galbraith
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