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Date:      Tue, 5 Oct 2004 11:41:05 +0300
From:      Giorgos Keramidas <keramida@ceid.upatras.gr>
To:        Joe Schmoe <non_secure@yahoo.com>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: tracking per process IO usage / stats ... help needed..
Message-ID:  <20041005084105.GA1837@orion.daedalusnetworks.priv>
In-Reply-To: <20041004131500.9587.qmail@web53308.mail.yahoo.com>
References:  <20041004131500.9587.qmail@web53308.mail.yahoo.com>

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On 2004-10-04 06:15, Joe Schmoe <non_secure@yahoo.com> wrote:
>
> I have a FreeBSD system (4.9) running a fair number of processes in a
> multi-user / shell hosting environment.
>
> One problem that routinely comes up is that the system will seem to be
> fine in terms of CPU, and none of the top 10 or 15 processes that I
> see in "top" are using much CPU ... but the load average is very high
> - sometimes as high as 30 or 40 ...
>
> I have good reason to suspect that the load is high due to I/O.  I can
> see the number of processes blocking on I/O in vmstat, and I can see
> iostat for the entire machine, of course ...

You might want to see if the "io" mode of top can be ported to RELENG_4.
In 5.X you can use top to display io statistics too:

: $ top -m io | sed -e 1,7d | head -10
:   PID USERNAME   VCSW  IVCSW   READ  WRITE  FAULT  TOTAL PERCENT COMMAND
:  1742 keramida  32250   2182    278      7   1376   1661  28.90% Xorg
:  1829 keramida   5617   1601    440      4    472    916  15.94% mozilla-bin
:   416 root       5031   5119      0      0      1      1   0.02% moused
:  1745 keramida  19871    517     65      0     22     87   1.51% wmaker
:  1789 keramida   5264    425      2      0      1      3   0.05% xterm-static
:  1837 keramida    643    205     17    188      6    211   3.67% mutt
:  1792 keramida   2640   1023      0      0      0      0   0.00% screen
:  1949 keramida    260    118      0     16      1     17   0.30% emacs
:   293 root        702    181      9      3      0     12   0.21% syslogd

The differences of top from RELENG_4 to CURRENT are many and I don't have the
time right now to try porting the "io mode" stuff to RELENG_4, but if you
cannot do it yourself I might find a bit of time this weekend.

- Giorgos



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