Message-ID: <465B4B75.2040602@tmr.com>
Date: Mon, 28 May 2007 17:36:53 -0400
From: Bill Davidsen <davidsen@tmr.com>
Organization: TMR Associates Inc, Schenectady NY
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.8) Gecko/20061105 SeaMonkey/1.0.6
MIME-Version: 1.0
To: Linux Kernel mailing List <linux-kernel@vger.kernel.org>
Subject: What causes iowait other than waiting for i/o?
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1057
Lines: 23

I recently noted that my system was spending a lot of time in i/o wait 
when doing some tasks which I thought didn't involve i/o, as noted by 
the lack of disk light activity most of the time. I thought of network, 
certainly the NIC had no activity for this job. So I set up a little 
loop to capture all disk i/o and network activity (including loopback). 
That was no obvious help, and the program doesn't use pipes.

At this point I'm really curious, does someone have a good clue?

Note: I don't think this is a bug or performance issue, unless the 
kernel is doing something and charging time to iowait instead of system 
I don't see anything to fix, but I would like to understand.

-- 
bill davidsen <davidsen@tmr.com>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/