Date: Thu, 28 Dec 1995 01:40:20 +0100 (MET) From: Mattias.Gronlund@sa.erisoft.se (Mattias Gronlund) To: se@zpr.uni-koeln.de (Stefan Esser) Cc: freebsd-hackers@FreeBSD.org Subject: Re: iostat and msps Message-ID: <9512280040.AA04766@sws021.sa.erisoft.se> In-Reply-To: <199512271546.AA16282@Sysiphos> from "Stefan Esser" at Dec 27, 95 04:46:23 pm
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On Wed, 27 Dec 1995 16:46 Stefan Esser wrote: > Well, if we agree on some standard format, I'll make the NCR driver > create the necessary data ... I think it would be great if we could agree on some standard format. Here's a proposal of parameters that whould be nice to collect: a busy (clock ticks) b read_transfers (number of) c write_transfers (number of) d read_bytes (number of) e write_bytes (number of) f queue_length (sum of the queue length when transfer initiated) g wait (clock ticks when the wueue length > 1) h serve_length (sum of the serve queue length when transfer initiated) i fly_interrupts (number of) j brk_interrupts (number of) k expected_disconnects (number of) l unexpected_disconnects (number of) Is there any device that can serve more then I request at a time that would need (h)? I guess k and l only is relevant for scsi devices but it would be nice to have them avaible. If we let the statistics and the number of clockticks from boot (t) to be read together by one sysctl call, I think we could calculate at least the following intresting information from the collected data: Average number of bytes read per transfer = d / b Average number of bytes write per transfer = e / c Average number of bytes read per clocktick = d / t Average number of bytes write per clocktick = e / t Average number of read transfers per clocktick = b / t Average number of write transfers per clocktick = c / t Average number of requests on queue = f / (b+c) Average number of requests on serve queue = h / (b+c) Average service time = a / (b+c) Percent busy = 100 * a / t Percent wait = 100 * g / t /Mattias
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