Re: command piped into bzip not using all available CPU
From: Jim C. Nasby (jim_at_nasby.net)
Date: 04/20/04
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- In reply to: Scott Lambert: "Re: command piped into bzip not using all available CPU"
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Date: Tue, 20 Apr 2004 09:45:47 -0500 To: freebsd-performance@freebsd.org
decibel@fritz.1[9:34]~:6>uname -a
FreeBSD fritz.distributed.net 5.2.1-RELEASE FreeBSD 5.2.1-RELEASE #1:
Wed Apr 7 18:42:52 CDT 2004
root@fritz.distributed.net:/usr/obj/usr/src/sys/FRITZ amd64
decibel@fritz.1[9:35]/usr/src/sys/amd64/conf:9>grep -i sched FRITZ
options SCHED_4BSD #4BSD scheduler
options _KPOSIX_PRIORITY_SCHEDULING #Posix P1003_1B real-time extensions
Also, don't read anything into the fact that they were on the same CPU
for that snapshot; here's one showing the exact opposite:
PID USERNAME PRI NICE SIZE RES STATE C TIME WCPU CPU COMMAND
10336 dnetc 139 20 1344K 856K RUN 1 80.5H 90.14% 90.14% dnetc
10702 decibel 108 0 10856K 7304K CPU0 1 0:13 23.86% 22.41% bzip2
10703 pgsql 4 0 154M 78004K sbwait 0 0:07 10.92% 10.25% postgres
FWIW, I recall seeing this same behavior under FreeBSD 4.x as well.
On Mon, Apr 19, 2004 at 11:27:16PM -0400, Scott Lambert wrote:
> On Mon, Apr 19, 2004 at 09:09:21AM -0500, Jim C. Nasby wrote:
> > Why would I expect to see it only use one CPU? It was CPU bound, not
> > disk bound. There were two CPU-intensive processes running, why wouldn't
> > they each use a different CPU?
> >
> > On Mon, Apr 19, 2004 at 12:08:32AM -0700, Aaron Seelye wrote:
> > > I'm not sure the exact technical reason, but as I understand that, it's
> > > 47% idle on the total cpu power of the machine, which would indicate
> > > that one cpu was 100% full, and the other was 3%, due to system usage,
> > > i/o, or whatever else was running. This is quite normal in my
> > > experience, and what you should expect to see.
>
> At the time you took the snapshot, both processes were running on the
> same CPU. FreeBSD 4.x or 5.2? If 5.2, SCHED_4BSD or SCHED_ULE?
>
> > > > The command I'm running is:
> > > > pg_dump -vZ0 ogr | bzip2 > ogr-20040416.sql.bz2
> > > >
> > > > PID USERNAME PRI NICE SIZE RES STATE C TIME WCPU CPU COMMAND
> > > > 17334 decibel 109 0 10856K 7164K CPU0 0 11:05 65.77% 65.77% bzip2
> > > > 17335 pgsql 4 0 154M 124M sbwait 0 5:54 34.03% 34.03% postgres
> > > > 17333 decibel -8 0 20128K 3236K pipdwt 0 0:46 2.88% 2.88% pg_dump
>
> --
> Scott Lambert KC5MLE Unix SysAdmin
> lambert@lambertfam.org
>
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>
-- Jim C. Nasby, Database Consultant jim@nasby.net Member: Triangle Fraternity, Sports Car Club of America Give your computer some brain candy! www.distributed.net Team #1828 Windows: "Where do you want to go today?" Linux: "Where do you want to go tomorrow?" FreeBSD: "Are you guys coming, or what?" _______________________________________________ freebsd-performance@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-performance To unsubscribe, send any mail to "freebsd-performance-unsubscribe@freebsd.org"
- Previous message: Q?=Igor ShmuklerQ=20?=: "Re[2]: How does disk caching work?"
- In reply to: Scott Lambert: "Re: command piped into bzip not using all available CPU"
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