Re: command piped into bzip not using all available CPU

From: Jim C. Nasby (jim_at_nasby.net)
Date: 04/19/04

  • Next message: Uwe Doering: "Re: How does disk caching work?" 
    Date: Sun, 18 Apr 2004 21:22:39 -0500
To: Aaron Seelye <aseelye-lists@eltopia.com>

    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?"
    > _______________________________________________
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    >
    >
    >
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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?"
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  • Next message: Uwe Doering: "Re: How does disk caching work?"

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