Date: Tue, 16 Jul 2002 23:29:57 +0100 From: Matthew Seaman <m.seaman@infracaninophile.co.uk> To: Oleg Borodkin <theboa@mail.ru> Cc: freebsd-questions@FreeBSD.ORG, dinorep1@nitroclicks.com Subject: Re: Top utility Message-ID: <20020716222957.GB37671@happy-idiot-talk.infracaninophi> In-Reply-To: <004b01c22d06$e1c7b310$01004280@irridium> References: <004b01c22d06$e1c7b310$01004280@irridium>
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On Wed, Jul 17, 2002 at 12:25:08AM +0400, Oleg Borodkin wrote:
> The 'top' utility shows 25-30% system load. It seems to be too high
> - what do the system does? How I can trace it?
Look at the top output and figure out what the processes are that are
hitting your system hardest. Use truss(1) or ktrace(1) to trace out
what system calls those processes are making. Care: injudicious use of
ktrace(1) can bring a system to it's knees and really spoil your whole
day.
Use `systat -vm' for a good summary screen showing process, VM,
network and disk activity. That might give you some clues about
what's happening.
It's not impossible for your machine to legitimately have it's CPU
spending 25-30% of the time performing system calls --- but the
machine would have to be fairly well loaded and the other CPU states
(except idle) would probably be high as well.
The effect might be caused by marginal hardware: eg. a disk that takes
a few retries to do an IO operation, or a network flooded with bogus
packets from a NIC gone bad. Check system logs for indications of
impending failure and make some good backups. If you have sufficient
time, motivation and spare parts try removing or swapping out
components to see if it makes a difference -- sometimes it's amazing
what a difference replacing a damaged Ethernet cable can make.
Cheers,
Matthew
--
Dr Matthew J Seaman MA, D.Phil. 26 The Paddocks
Savill Way
Tel: +44 1628 476614 Marlow
Fax: +44 0870 0522645 Bucks., SL7 1TH UK
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