Re: command piped into bzip not using all available CPU

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Date: Mon, 19 Apr 2004 09:09:21 -0500
To: Aaron Seelye <aseelye-lists@eltopia.com>

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.
>
> -Aaron
> ----- Original Message -----
> From: "Jim C. Nasby" <jim@nasby.net>
> To: "Aaron Seelye" <aseelye-lists@eltopia.com>
> Cc: <freebsd-performance@freebsd.org>
> Sent: Sunday, April 18, 2004 7:22 PM
> Subject: Re: command piped into bzip not using all available CPU
>
>
> Perhapse I didn't make it clear, but this is on a dual CPU machine. I
> would expect that either bzip2 or pgsql would hit 100% CPU, using one
> entire CPU. The 47% idle indicates to me that it's not.
>
> On Fri, Apr 16, 2004 at 03:48:19PM -0700, Aaron Seelye wrote:
> > I would venture a guess that bzip is not multi threaded and therefore
> > isn't spreading the load around.
> >
> > -Aaron Seelye
> > ----- Original Message -----
> > From: "Jim C. Nasby" <jim@nasby.net>
> > To: <freebsd-performance@freebsd.org>
> > Sent: Friday, April 16, 2004 3:05 PM
> > Subject: command piped into bzip not using all available CPU
> >
> >
> > As you can see below, a command piped into bzip2 is only effectively
> > using one CPU. It's not disk bound, both systat and gstat report less
> > than 10% disk utilization. Why is this?
> >
> > The command I'm running is:
> > pg_dump -vZ0 ogr | bzip2 > ogr-20040416.sql.bz2
> >
> > last pid: 18345; load averages: 1.17, 1.09, 0.81 up 8+22:12:27
> > 17:00:56
> > 66 processes: 2 running, 64 sleeping
> > CPU states: 49.4% user, 0.0% nice, 3.7% system, 0.2% interrupt,
> 46.7%
> > idle
> > Mem: 67M Active, 2935M Inact, 359M Wired, 331M Cache, 255M Buf, 5576K
> > Free
> > Swap: 8192M Total, 64M Used, 8127M Free, 48K Out
> >
> > 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
> > --
> > 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"
> >
> >
> >
> > _______________________________________________
> > freebsd-performance@freebsd.org mailing list
> > http://lists.freebsd.org/mailman/listinfo/freebsd-performance
> > To unsubscribe, send any mail to
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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?"
>
>
>

-- 
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?"
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