From owner-freebsd-hackers  Wed May 15 11: 7:31 2002
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Date: Wed, 15 May 2002 14:07:05 -0400 (EDT)
From: Zhihui Zhang <zzhang@cs.binghamton.edu>
X-Sender: zzhang@onyx
To: Alfred Perlstein <bright@mu.org>
Cc: Terry Lambert <tlambert2@mindspring.com>,
	Doug White <dwhite@resnet.uoregon.edu>, freebsd-hackers@FreeBSD.ORG
Subject: Re: Collect process sleeping statistics
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What if most I/O are asynchronous writes and handled by a background
process (e.g. SoftUpdate syncer daemon or a special kernel daemon), then I
guess the wait should have something to do with memory or buffer. But I do
not know to to confirm this. Maybe some profiling or instrumentation (too
much work?) will help.

-Zhihui

On Wed, 15 May 2002, Alfred Perlstein wrote:

> * Zhihui Zhang <zzhang@cs.binghamton.edu> [020515 10:33] wrote:
> > 
> > Basically I have a program that does a lot of I/O and alloctes/frees a lot
> > of memory. The time command gives result like this:
> > 
> > 6.239u 19.329s 7:59.76 5.3%	310+775k 3993+246io 7pf+0w
> > 
> > I want to know why CPU is running only 5.3% of the total time. I just
> > want know how long it is waiting for memory and how long it is waiting for
> > I/O.  No other process is running at the same time.
> 
> When not condending against other processes, almost all time not
> spent on CPU is waiting for IO.
> 
> -Alfred
> 
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