Date: Wed, 15 Nov 2000 17:30:54 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: riel@conectiva.com.br (Rik van Riel) Cc: tlambert@primenet.com (Terry Lambert), float@firedrake.org (void), hackers@FreeBSD.ORG Subject: Re: "iowait" CPU state Message-ID: <200011151730.KAA12666@usr01.primenet.com> In-Reply-To: <Pine.LNX.4.21.0011141720170.25493-100000@duckman.distro.conectiva> from "Rik van Riel" at Nov 14, 2000 05:21:09 PM
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> > > Thank you! This gets the me disk %busy, which is one of the things I > > > was looking for. Now, can anyone tell me how to tell what percentage of > > > processor time is being spent waiting for disk I/O to complete? > > > > Uh, none? > > > > If there is disk I/O pending, the processor just runs a > > different process... am I missing your question? > > I guess it might be useful to see the difference between > "true" idle time and time the system couldn't do anything > useful because it was blocked on the disk (but /should/ > have done something useful...). You mean because the programmer didn't interleave their I/O, and wrote to a threads interface, or some other interface that's prone to subsystem stalling, instead? I think you get what you pay for, when it comes to engineering skill. It's easy to write code that stalls, and then expect to be able to throw clock-doubled hardware at it to "fix it". I'm always tempted to set up a company where the main engineers have a centralized batch compile server, so as to not slow down developement, but requiring that they run no better than a 386SX/16 on their desktop. If they are good, I'd give them a full 8M of real RAM, instead of 4M. Modern bloat-ware really pisses me off; I built the bind library the other day: the frigging thing was 4M, unstripped. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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