SUMMARY: Performance question

From: Jan Dreyer <dreyerja_at_uni-paderborn.de>
Date: Thu Apr 03 2008 - 10:10:26 EDT
Hi @ll,

thanks for answers to
Bill Voight
przemol
Darren Dunham
Roberto Fratelli

They mostly pointed to the very usefull scripts included in the dtrace 
toolkit, available at 
http://opensolaris.org/os/community/dtrace/dtracetoolkit/

Brendan Gregg published some scripts on 
http://www.brendangregg.com/k9toolkit.html

Also very good is the guide on 
http://www.sun.com/software/solaris/howtoguides/dtracehowto.jsp

I did'nt have had a lot process creation or forking.
After running 'topsyscall' and 'topsysproc' I identified  some processes 
that made a lot of reads and writes. But these applications didn't 
change in the past months, so they were not likely the cause.

A look at the syslog showed that the automounter tried to mount 
something on /net every minute. I disabled /net as we don't use it 
anyway. But the performance issue still stayed.

Last (ugly) resort was to reboot the machine.
Till now (~2h) that did it. But as the behaviour wasn't persistent but 
occured casually, I can't say, if we really got it.
Maybe tomorrow or so ...

Greetings
Jan Dreyer

Jan Dreyer wrote:
> Hi managers,
> 
> we have a E3500 (5.10 Generic_127111-06) with some trouble completing 
> it's job(s). The problem is, I can't identify the source of the dilemma.
> 
> sar shows:
> 13:55:17    %usr    %sys    %wio   %idle
> 13:55:19      11      89       0       0
> 13:55:20      10      88       0       2
> 13:55:24      10      89       0       1
> 13:55:26      10      89       0       1
> 13:55:27       9      91       0       0
> 13:55:29       6      94       0       0
> 13:55:31       4      96       0       0
> 
> so the processes are in system mode about 85-99%! That's way too much. 
> But I can't see, why this occurs. Obviously there is few IO, so this 
> doesn't block.
> 
> Dtrace seems the answer, but I have no idea which of the millions of 
> screws I shall turn there ...
> 
> Any hints here, where and how to look?
> 
> Greetings and thanks in advance
> Jan Dreyer
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Received on Thu Apr 3 09:14:12 2008

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