Re: command piped into bzip not using all available CPU

From: Scott Lambert (lambert_at_lambertfam.org)
Date: 04/20/04

  • Next message: Uwe Doering: "Re: How does disk caching work?" 
    Date: Mon, 19 Apr 2004 23:27:16 -0400
To: freebsd-performance@freebsd.org

    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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