command piped into bzip not using all available CPU

From: Jim C. Nasby (jim_at_nasby.net)
Date: 04/17/04

  • Next message: Q?=Igor ShmuklerQ=20?=: "Re[2]: How does disk caching work?" 
    Date: Fri, 16 Apr 2004 17:05:56 -0500
To: freebsd-performance@freebsd.org

    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
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