Date: Wed, 5 Feb 2003 11:52:14 +1030 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: phk@freebsd.org Cc: Brad Knowles <brad.knowles@skynet.be>, current@freebsd.org Subject: Re: Preview: GEOMs statistics code. Message-ID: <20030205012214.GG12525@wantadilla.lemis.com> In-Reply-To: <27759.1044403667@critter.freebsd.dk> References: <a05200f08ba65f714a4e9@[146.106.12.76]> <27759.1044403667@critter.freebsd.dk>
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On Wednesday, 5 February 2003 at 1:07:47 +0100, Poul-Henning Kamp wrote: > In message <a05200f08ba65f714a4e9@[146.106.12.76]>, Brad Knowles writes: >> At 10:44 PM +0100 2003/02/04, Poul-Henning Kamp wrote: >> >>> In difference from the devstat framework which measures how big a >>> percentage of the time a drive has one or more outstanding requests, >>> I think that measuring the responstime is a much more useful metric. >>> (comments, input, references welcome) >> >> This is queue depth versus latency, right? I don't suppose a >> request to provide both would hold any weight with you, would it? > > I'm 100% wide open to suggestions. Anything I can trivally account > for is fair game. It looks like there are at least three statistics of interest: 1. Response time. 2. %busy. I personally think this is the most important one, but as you say, there's no reason not to do the others as well. 3. Average number of requests waiting. > I don't have a queue-depth as such, but I have number of > transactions in transit. Will a snapshot of that at the time of the > read do what you want ? What's the difference? I would have thought that's the same thing. > I won't be locking the stats counters, so reads may get inconsistent > results. This looks like a correct decision to me. I can't see any disadvantage in slightly incorrect values, as long as they don't accumulate. Greg -- See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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