Re: a serious error in sched_ule.c?
Wes Peters [EMAIL PROTECTED] writes: On Mon, 15 Mar 2004 07:42:59 + Colin Percival [EMAIL PROTECTED] alleged: At 07:32 15/03/2004, Dag-Erling Smrgrav wrote: Actually, my wife is a molecular biologist and eats CPU hours with milk and sugar for breakfast. She expressed her satisfaction yesterday at finding out that her latest program only takes four and a half hours per data set. But honey, says I, you have 30,000 data sets! Quoth the love of my life, That's OK, we've got *two* computers. ... and 8 years to waste, apparently. Wowsers. Sounds like they need a cluster. Actually, the computers in question have 160 CPUs each, so she should be done in about three weeks :) DES -- Dag-Erling Smrgrav - [EMAIL PROTECTED] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: a serious error in sched_ule.c?
On Sun, Mar 14, 2004 at 09:16:54PM -0800, Wes Peters wrote: Sigh. Nobody really does compute-bound tasks anymore, do they? I really miss scientific programming. [EMAIL PROTECTED], the mersenne prime project, protein folding and the list goes on (the mersenne prime project web site includes an extensive list of other ways to help your CPU avoid the idle loop). I suspect more people now have a compute-bound process soaking their idle cycles than ever before. (Of course, these processes need to be using an interactive scheduler so the user doesn't notice the background process - even if the compute-bound task runs a bit slower as a result). Of course this isn't quite the same as a vector supercomputer doing traditional scientific programming - but no-one's ported FreeBSD to a Cray yet. Peter ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: a serious error in sched_ule.c?
On Tue, 09 Mar 2004 21:29:54 +0100 [EMAIL PROTECTED] (Dag-Erling Smørgrav) alleged: Wes Peters [EMAIL PROTECTED] writes: One of the classic trade-offs in making a 'server' vs. 'workstation' operating system. Workstations require a strong preference for interactive over background tasks so the interactive tasks will remain responsive, especially in terms of heavily event-driven tasks like graphical UIs. For a true server, where interactive tasks are not the norm, this preference may be counter-productive. Umm, remember that interactive here means performs I/O, even if that I/O is a database lookup or a TCP connection. Sigh. Nobody really does compute-bound tasks anymore, do they? I really miss scientific programming. -- Where am I, and what am I doing in this handbasket? Wes Peters [EMAIL PROTECTED] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: a serious error in sched_ule.c?
Wes Peters [EMAIL PROTECTED] writes: Sigh. Nobody really does compute-bound tasks anymore, do they? I really miss scientific programming. Actually, my wife is a molecular biologist and eats CPU hours with milk and sugar for breakfast. She expressed her satisfaction yesterday at finding out that her latest program only takes four and a half hours per data set. But honey, says I, you have 30,000 data sets! Quoth the love of my life, That's OK, we've got *two* computers. DES -- Dag-Erling Smrgrav - [EMAIL PROTECTED] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: a serious error in sched_ule.c?
At 07:32 15/03/2004, Dag-Erling Smørgrav wrote: Actually, my wife is a molecular biologist and eats CPU hours with milk and sugar for breakfast. She expressed her satisfaction yesterday at finding out that her latest program only takes four and a half hours per data set. But honey, says I, you have 30,000 data sets! Quoth the love of my life, That's OK, we've got *two* computers. ... and 8 years to waste, apparently. Colin Percival ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: a serious error in sched_ule.c?
On Mon, 15 Mar 2004 07:42:59 + Colin Percival [EMAIL PROTECTED] alleged: At 07:32 15/03/2004, Dag-Erling Smørgrav wrote: Actually, my wife is a molecular biologist and eats CPU hours with milk and sugar for breakfast. She expressed her satisfaction yesterday at finding out that her latest program only takes four and a half hours per data set. But honey, says I, you have 30,000 data sets! Quoth the love of my life, That's OK, we've got *two* computers. ... and 8 years to waste, apparently. Wowsers. Sounds like they need a cluster. Introduce her to Dillon! ;^) -- Where am I, and what am I doing in this handbasket? Wes Peters [EMAIL PROTECTED] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: a serious error in sched_ule.c?
On Tuesday 09 March 2004 08:41 am, Robert Watson wrote: On 9 Mar 2004, Bin Ren wrote: I've been reading sched_ule.c and seem to find a serious error: in 'sched_slice()': * Rationale: * KSEs in interactive ksegs get the minimum slice so that we * quickly notice if it abuses its advantage. . #define SCHED_SLICE_INTERACTIVE (slice_max) (slice_max) for interactive KSEs Either this is a serious mistake or I'm seriously missing sth here. I believe this is a synchronization error in the comment and the code. The code was changed to provide a maximum slice to interactive applications because non-CPU intensive X11 applications will be marked as interactive, but redraws get interrupted in a short slice. When the change went in to increase the time slice I saw an observable improvement in the redraws of X11 apps under load. One of the classic trade-offs in making a 'server' vs. 'workstation' operating system. Workstations require a strong preference for interactive over background tasks so the interactive tasks will remain responsive, especially in terms of heavily event-driven tasks like graphical UIs. For a true server, where interactive tasks are not the norm, this preference may be counter-productive. Is there some way (boot hint?) we could change SCHED_SLICE_INTERACTIVE between slice_max and something approaching slice_min? -- Where am I, and what am I doing in this handbasket? Wes Peters [EMAIL PROTECTED] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: a serious error in sched_ule.c?
Wes Peters [EMAIL PROTECTED] writes: One of the classic trade-offs in making a 'server' vs. 'workstation' operating system. Workstations require a strong preference for interactive over background tasks so the interactive tasks will remain responsive, especially in terms of heavily event-driven tasks like graphical UIs. For a true server, where interactive tasks are not the norm, this preference may be counter-productive. Umm, remember that interactive here means performs I/O, even if that I/O is a database lookup or a TCP connection. DES -- Dag-Erling Smørgrav - [EMAIL PROTECTED] ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: a serious error in sched_ule.c?
On 9 Mar 2004, Bin Ren wrote:
Hi, all:
I've been reading sched_ule.c and seem to find a serious error:
in 'sched_slice()':
* Rationale:
* KSEs in interactive ksegs get the minimum slice so that we
* quickly notice if it abuses its advantage.
Then, there is:
if (!SCHED_INTERACTIVE(kg)) {
.
.
} else
ke-ke_slice = SCHED_SLICE_INTERACTIVE;
Then, at the beginning of the file, there is:
#define SCHED_SLICE_INTERACTIVE (slice_max)
(slice_max) for interactive KSEs Either this is a serious mistake or
I'm seriously missing sth here.
I believe this is a synchronization error in the comment and the code.
The code was changed to provide a maximum slice to interactive
applications because non-CPU intensive X11 applications will be marked as
interactive, but redraws get interrupted in a short slice. When the
change went in to increase the time slice I saw an observable improvement
in the redraws of X11 apps under load.
Robert N M Watson FreeBSD Core Team, TrustedBSD Projects
[EMAIL PROTECTED] Senior Research Scientist, McAfee Research
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