Date: Thu, 12 Nov 1998 13:11:37 -0700 (MST) From: "Kenneth D. Merry" <ken@plutotech.com> To: dillon@apollo.backplane.com (Matthew Dillon) Cc: aron@cs.rice.edu, freebsd-hackers@FreeBSD.ORG Subject: Re: scsi disk queue Message-ID: <199811122011.NAA24806@panzer.plutotech.com> In-Reply-To: <199811121938.LAA28728@apollo.backplane.com> from Matthew Dillon at "Nov 12, 98 11:38:36 am"
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Matthew Dillon wrote... > Neat! I hope you don't mind if I modify the program some. > > http://www.backplane.com/FreeBSD/dds.c No problem. Looks interesting. > For ongoing reporting of read activity, write activity (avg per second), > busy percentage, and request backlog. > > The busy percentage is especially useful. I would take the busy time stuff with a grain of salt. It is only updated when the busy count goes to zero. (to save CPU cycles, among other things) So if the disk stays busy for 10 seconds, the busy time won't get updated until the end of that 10 second period. So this can have some interesting results (using a 1 second update): da0 da1 22.4k 15.6k 2%/0 5.9k 5.76m 65%/10 31.9k 8.0k 4%/0 6.0k 4.11m 76%/21 2.0k 39.6k 0%/0 25.7k 5.75m 0%/24 14.9k 7.9k 0%/0 31.7k 5.02m 147%/18 118k 87.1k 16%/0 11.9k 4.03m 148%/10 0.0k 31.7k 0%/0 25.7k 7.12m 0%/12 0.0k 0.0k 0%/0 17.8k 7.87m 0%/18 28.7k 0.0k 3%/0 19.8k 203k 223%/10 > % ./dds da1 da2 da3 10 > nntp1:/news> ./dds da1 da2 da3 10 > da1 da2 da3 > 625k 142k 75%/0 644k 155k 70%/2 652k 137k 72%/1 > 763k 78.6k 77%/2 792k 96.9k 80%/3 840k 86.4k 80%/2 > 696k 153k 77%/3 693k 172k 83%/2 702k 163k 80%/4 [ ... ] > :If you're running 3.0 or a CAM version of -current or -stable, you can find > :out the number of outstanding transactions for any device registered with > :the devstat(9) subsystem. > : > :Download the following program: > : > :ftp://ftp.kdm.org/pub/FreeBSD/cam/ds.c > : > :It dumps out the devstat entry for each device. The devstat entry includes > :a busy count, which is the number of outstanding transactions queued to the > :drive. > : > :Ken > :-- > :Kenneth Merry > :ken@plutotech.com > Ken -- Kenneth Merry ken@plutotech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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