From: Bill Davidsen <davidsen@tmr.com>
To: jg@laptop.org
Cc: Ingo Molnar <mingo@elte.hu>, Pavel Machek <pavel@ucw.cz>,
Ash Milsted <thatistosayiseenem@gawab.com>,
dmitry.torokhov@gmail.com, Arkadiusz Miskiewicz <arekm@maven.pl>,
linux-pm@lists.osdl.org, Jens Axboe <jens.axboe@oracle.com>,
linux-input@atrey.karlin.mff.cuni.cz,
Alexey Starikovskiy <alexey.y.starikovskiy@linux.intel.com>,
linux-usb-devel@lists.sourceforge.net,
Jeff Chua <jeff.chua.linux@gmail.com>,
Meelis Roos <mroos@linux.ee>,
Janosch Machowinski <jmachowinski@gmx.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Adrian Bunk <bunk@stusta.de>,
linux-acpi@vger.kernel.org,
"Eric W. Biederman" <ebiederm@xmission.com>,
Thomas Meyer <thomas.mey@web.de>,
"Michael S. Tsirkin" <mst@mellanox.co.il>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [linux-pm] [2/6] 2.6.21-rc2: known regressions
Date: Tue, 20 Mar 2007 10:44:44 -0400 [thread overview]
Message-ID: <45FFF35C.20003@tmr.com> (raw)
In-Reply-To: <1174342101.6832.173.camel@localhost>
Jim Gettys wrote:
> On Mon, 2007-03-19 at 16:33 -0400, Bill Davidsen wrote:
>
>
>> What you say sounds good, assuming that the cost of a sleep is less than
>> the cost of the busy wait. But this may be hardware, the waits may be
>> very small and frequent, and if it's hitting a small hardware window
>> like retrace, delays in response will cause the time period to be missed
>> completely. This probably less critical with very smart cards, many of
>> us don't run them.
>>
>
> Actually, various strategies involving short busy waiting, or looking at
> DMA address registers before sleeping were commonplace. But a
> syscall/sleep/wakeup is/was pretty fast. If you have an operation
> blitting the screen (e.g. scrolling), it takes a bit of time for the GPU
> to execute the command. I see this right now on OLPC, where a wonderful
> music application needs to scroll (most of) the screen left),
> periodically, and we're losing samples sometimes at those operation.
>
None of that conflicts with what I said, but what works on an LCD may
not be appropriate for a CRT. With even moderate 1024x768@70 timing the
horizontal retrace happens ~50k/sec, and that's not an appropriate
syscall rate. I'm just pointing out that some things a video interface
does with simple hardware involve lots of very small windows. Don't read
that as "don't do it," just "be careful HOW you do it."
> Remember also, that being nice to everyone else by sleeping, there are
> more cycles to go around, and the scheduler can nicely boost the X
> server's priority as it will for "interactive" processes that are being
> cooperative.
I'm going to cautiously guess that the problem might be not "how much"
but "how soon." That is, latency might be more important than giving the
server a lot of CPU.
--
bill davidsen <davidsen@tmr.com>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
next prev parent reply other threads:[~2007-03-20 14:43 UTC|newest]
Thread overview: 187+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-28 5:16 Linux 2.6.21-rc2 Linus Torvalds
2007-02-28 5:50 ` Gabriel C
2007-02-28 7:13 ` [PATCH] affinity is not defined in non-smp kernels - i386 Fernando Luis Vázquez Cao
2007-02-28 7:16 ` [PATCH] affinity is not defined in non-smp kernels - i386 (v2) Fernando Luis Vázquez Cao
2007-02-28 7:24 ` [PATCH] affinity is not defined in non-smp kernels - i386 Eric W. Biederman
2007-02-28 17:31 ` Bill Davidsen
2007-02-28 18:21 ` Eric W. Biederman
2007-02-28 18:30 ` Linus Torvalds
2007-02-28 7:42 ` [PATCH] affinity is not defined in non-smp kernels - i386 (v2) Fernando Luis Vázquez Cao
2007-02-28 7:17 ` [PATCH] affinity is not defined in non-smp kernels - x86_64 Fernando Luis Vázquez Cao
2007-02-28 7:23 ` Linux 2.6.21-rc2 David Brown
2007-02-28 7:39 ` Brice Goglin
2007-02-28 13:09 ` Eric W. Biederman
2007-02-28 16:44 ` David Brown
2007-02-28 17:07 ` Randy Dunlap
2007-02-28 7:41 ` [PATCH] affinity is not defined in non-smp kernels - x86_64 Fernando Luis Vázquez Cao
2007-02-28 7:59 ` Linux 2.6.21-rc2 Damien Wyart
2007-03-05 1:50 ` [1/6] 2.6.21-rc2: known regressions Adrian Bunk
2007-03-05 2:26 ` Andrew Morton
2007-03-05 3:35 ` Greg KH
2007-03-06 0:55 ` Johannes Berg
2007-03-05 4:01 ` Mark Lord
2007-03-05 4:34 ` Greg KH
2007-03-05 12:42 ` Marcel Holtmann
2007-03-05 4:34 ` [BUG} usb regression in 2.6.21-rc2-git3 Mark Lord
2007-03-05 4:37 ` [BUG] sdhci regression in 2.6.21-rc2 Mark Lord
2007-03-05 5:36 ` Pierre Ossman
2007-03-05 14:25 ` Mark Lord
2007-03-05 15:19 ` Mark Lord
2007-03-06 4:17 ` Andrew Morton
2007-03-06 5:47 ` Pierre Ossman
2007-03-06 6:09 ` Andrew Morton
2007-03-06 7:23 ` Pierre Ossman
2007-03-05 15:20 ` Pierre Ossman
2007-03-05 15:23 ` Pierre Ossman
2007-03-05 15:35 ` Mark Lord
2007-03-05 16:00 ` Pierre Ossman
2007-03-05 16:18 ` Mark Lord
2007-03-05 4:43 ` [BUG} usb regression in 2.6.21-rc2-git3 Mark Lord
2007-03-12 14:56 ` [BUG} usb-serial " Mark Lord
2007-03-12 15:06 ` Oliver Neukum
2007-03-12 15:13 ` Mark Lord
2007-03-12 15:27 ` Oliver Neukum
2007-03-12 15:29 ` Greg KH
2007-03-12 15:38 ` Oliver Neukum
2007-03-12 16:03 ` Mark Lord
2007-03-12 16:10 ` Greg KH
2007-03-12 16:22 ` Mark Lord
2007-03-12 16:11 ` Mark Lord
2007-03-12 16:14 ` Mark Lord
2007-03-12 16:27 ` Mark Lord
2007-03-12 16:50 ` Mark Lord
2007-03-12 18:48 ` Oliver Neukum
2007-03-12 20:22 ` [PATCH] usb-serial regression (Oops) in 2.6.21-rc* Mark Lord
2007-03-12 20:33 ` Greg KH
2007-03-12 22:20 ` Mark Lord
2007-03-12 22:42 ` Jim Radford
2007-03-12 22:59 ` [PATCH] usb-serial regression fix Jim Radford
2007-03-13 0:18 ` Greg KH
2007-03-13 0:41 ` Jim Radford
2007-03-13 1:55 ` Mark Lord
2007-03-13 9:14 ` Jim Radford
2007-03-13 10:14 ` Oliver Neukum
2007-03-13 13:39 ` Mark Lord
2007-03-13 13:50 ` Oliver Neukum
2007-03-13 13:55 ` Mark Lord
2007-03-13 15:30 ` Jim Radford
2007-03-13 16:35 ` Mark Lord
2007-03-12 16:28 ` [BUG} usb-serial regression in 2.6.21-rc2-git3 Oliver Neukum
2007-03-12 15:31 ` Greg KH
2007-03-07 11:06 ` [1/6] 2.6.21-rc2: known regressions Jeff Garzik
2007-03-07 22:17 ` Albert Hopkins
2007-03-05 1:50 ` [2/6] " Adrian Bunk
2007-03-07 11:09 ` Jeff Garzik
2007-03-07 16:10 ` Linus Torvalds
2007-03-08 12:03 ` Ash Milsted
2007-03-08 12:31 ` Michael S. Tsirkin
2007-03-08 15:11 ` Jeff Chua
2007-03-08 18:01 ` Linus Torvalds
2007-03-08 19:06 ` Ingo Molnar
2007-03-08 19:10 ` Ingo Molnar
2007-03-08 19:47 ` Michael S. Tsirkin
2007-03-08 20:10 ` Ingo Molnar
2007-03-08 19:25 ` Ingo Molnar
2007-03-08 23:07 ` Ingo Molnar
2007-03-08 23:12 ` Ingo Molnar
2007-03-08 23:28 ` Ingo Molnar
2007-03-08 23:49 ` Linus Torvalds
2007-03-09 10:56 ` Ingo Molnar
2007-03-09 18:00 ` Linus Torvalds
2007-03-09 11:19 ` Pavel Machek
2007-03-18 16:07 ` Ingo Molnar
2007-03-18 16:40 ` [linux-pm] " Jim Gettys
2007-03-19 19:08 ` BSOD (was: [2/6] 2.6.21-rc2: known regressions) Pete Zaitcev
2007-03-19 19:38 ` BSOD David Miller
2007-03-19 19:54 ` BSOD Jesse Barnes
2007-03-19 20:05 ` BSOD David Miller
2007-03-19 20:20 ` BSOD Jesse Barnes
2007-03-19 20:20 ` BSOD Jim Gettys
2007-03-20 9:19 ` BSOD Paul Mackerras
2007-03-20 20:33 ` BSOD Jim Gettys
2007-03-19 20:33 ` [linux-pm] [2/6] 2.6.21-rc2: known regressions Bill Davidsen
2007-03-19 22:08 ` Jim Gettys
2007-03-20 14:44 ` Bill Davidsen [this message]
2007-03-09 17:48 ` Johannes Stezenbach
2007-03-09 23:35 ` Pavel Machek
2007-03-10 9:01 ` Ingo Molnar
2007-03-10 11:43 ` Stefan Seyfried
2007-03-10 13:53 ` Johannes Stezenbach
2007-03-10 15:18 ` Ingo Molnar
2007-03-10 22:08 ` Pavel Machek
2007-03-11 8:20 ` Ingo Molnar
2007-03-12 6:34 ` Stefan Seyfried
2007-03-10 22:04 ` s2ram (was Re: [2/6] 2.6.21-rc2: known regressions) Pavel Machek
2007-03-08 19:46 ` [2/6] 2.6.21-rc2: known regressions Michael S. Tsirkin
2007-03-08 19:57 ` Michael S. Tsirkin
[not found] ` <20070311120802.GA8823@elte.hu>
2007-03-12 20:20 ` Michael S. Tsirkin
2007-03-17 21:41 ` Michael S. Tsirkin
2007-03-17 22:33 ` Thomas Gleixner
2007-03-21 17:28 ` Michael S. Tsirkin
2007-03-05 1:50 ` [3/6] " Adrian Bunk
2007-03-05 3:58 ` Michal Jaegermann
2007-03-06 17:08 ` Alan Cox
2007-03-07 11:12 ` Jeff Garzik
2007-03-10 1:09 ` Mathieu Bérard
2007-03-10 4:11 ` and try remove another quirk on this computers " Sergio Monteiro Basto
2007-03-10 5:41 ` Linus Torvalds
2007-03-11 4:32 ` Sergio Monteiro Basto
2007-03-12 11:37 ` Tejun Heo
2007-03-13 12:31 ` Mathieu Bérard
2007-03-13 12:41 ` Tejun Heo
2007-03-13 20:56 ` Mathieu Bérard
2007-03-14 6:07 ` Tejun Heo
2007-03-14 10:49 ` Mathieu Bérard
2007-03-05 1:50 ` [4/6] " Adrian Bunk
2007-03-05 10:35 ` Antonino A. Daplas
2007-03-05 15:06 ` Andrew
2007-03-08 23:28 ` Len Brown
2007-03-09 19:25 ` Andrew
2007-03-05 12:21 ` Richard Purdie
2007-03-05 1:50 ` [5/6] " Adrian Bunk
2007-03-05 7:57 ` Ingo Molnar
2007-03-05 8:13 ` Andrew Morton
2007-03-05 15:25 ` Daniel Walker
2007-03-05 15:27 ` Ingo Molnar
2007-03-05 16:42 ` Daniel Walker
2007-03-05 19:30 ` Ingo Molnar
2007-03-05 16:14 ` Bill Davidsen
2007-03-05 16:21 ` Ingo Molnar
2007-03-05 23:12 ` Adrian Bunk
2007-03-05 23:43 ` Thomas Gleixner
2007-03-05 23:45 ` Linus Torvalds
2007-03-06 0:25 ` Thomas Gleixner
2007-03-06 6:49 ` Soeren Sonnenburg
2007-03-06 7:49 ` Soeren Sonnenburg
2007-03-06 0:38 ` Linus Torvalds
2007-03-06 1:02 ` Thomas Gleixner
2007-03-06 1:31 ` Linus Torvalds
2007-03-06 2:18 ` Linus Torvalds
2007-03-06 7:25 ` Ingo Molnar
2007-03-06 8:09 ` Thomas Gleixner
2007-03-06 10:33 ` Michael S. Tsirkin
2007-03-06 10:37 ` Ingo Molnar
2007-03-06 10:46 ` Michael S. Tsirkin
2007-03-06 11:32 ` Ingo Molnar
2007-03-06 12:20 ` Michael S. Tsirkin
2007-03-06 16:44 ` Linus Torvalds
2007-03-06 17:05 ` Ingo Molnar
2007-03-06 17:29 ` [PATCH] highres: do not run the TIMER_SOFTIRQ after switching to highres mode Thomas Gleixner
2007-03-06 17:41 ` Linus Torvalds
2007-03-16 15:18 ` [5/6] 2.6.21-rc2: known regressions Randy Dunlap
2007-03-06 11:36 ` Soeren Sonnenburg
2007-03-06 12:07 ` Ingo Molnar
2007-03-06 12:15 ` Michael S. Tsirkin
2007-03-06 12:51 ` Ingo Molnar
2007-03-06 12:55 ` Michael S. Tsirkin
2007-03-06 13:03 ` Ingo Molnar
2007-03-06 13:09 ` Thomas Gleixner
2007-03-06 12:09 ` Jeff Chua
2007-03-11 17:32 ` Pavel Machek
2007-03-06 10:33 ` Michael S. Tsirkin
2007-03-05 1:50 ` [6/6] " Adrian Bunk
2007-03-05 2:07 ` David Miller
2007-03-05 2:26 ` Adrian Bunk
2007-03-05 2:29 ` David Miller
2007-03-05 4:42 ` David Miller
2007-03-05 3:32 ` Greg KH
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