command piped into bzip not using all available CPU

[Aaron Seelye]

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 at nasby.net>
To: "Aaron Seelye" <aseelye-lists at eltopia.com>
Cc: <freebsd-performance at 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 at nasby.net>
> To: <freebsd-performance at 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 at 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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--
Jim C. Nasby, Database Consultant                  jim at 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?"