Date: Wed, 15 May 2002 11:43:40 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Zhihui Zhang <zzhang@cs.binghamton.edu> Cc: Doug White <dwhite@resnet.uoregon.edu>, freebsd-hackers@FreeBSD.ORG Subject: Re: Collect process sleeping statistics Message-ID: <3CE2AC5C.5B511B16@mindspring.com> References: <Pine.SOL.4.21.0205151325290.17622-100000@onyx>
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Zhihui Zhang 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. You got 7 page faults with 0 waits. So it was waiting for I/O 94.7% of the time. That's statistical; the real calculation is 100% - 246/3993 = 93.8%. Generally, this comes down to a design issue that's very common in code these days, particularly code where people think "threads solve all concurrency problems". I think I should patent the correct way of solving this problem, since no one seems to use it. I'll call it "interleaved I/O"... -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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