we're running on sgi powerchallenge, 8 r10000 4-way smp, and we're getting bad performance from postgres, throughput increases from 1 to 5 streams, but from 5 and above there is no further increase, performance analysis show high sleep waiting for resources an example:

running(user mode) =32.57
running(system mode)=7.15
running(graphics mode)=0.21
waiting(for block I/O)=0.03
waiting(paging)=0.00
waiting(for memory)=0.00
waiting(in select)=17.13
waiting(in cpu queue)=0.26
sleep(for resource)=42.87

any tip?

thanks and regards

almost forget postgres7.2







we're running on sgi powerchallenge, 8 r10000 4-way 
smp, and we're getting bad performance from postgres, throughput increases from 
1 to 5 streams, but from 5 and above there is no further increase, performance 
analysis show high sleep waiting for resources an example:
 
running(user mode) =32.57
running(system mode)=7.15
running(graphics mode)=0.21
waiting(for block I/O)=0.03
waiting(paging)=0.00
waiting(for memory)=0.00
waiting(in select)=17.13
waiting(in cpu queue)=0.26
sleep(for resource)=42.87
 
any tip?
 
thanks and regards
 
almost forget 
postgres7.2
Tue, 12 Mar 2002 18:45:12 +0100
"Luis Alberto Amigo Navarro" <lamigo@atc.unican.es>
bad performance on irix
thanks for your answer, I send three mails detailing, you must have missed
one, briefing:
we're running a like tpch on an 8 processor machine, performance grows from
1 to 5 streams, but in 5 streams and up results get steady, I mean, the
results are measured on query-per-hour, it is obtained multiplying for the
number of streams and dividing for real time, so when your up of 5 streams
it is supposed than performance must grow up to 7 or 8 streams, but it gets
steady.
thank and regard


Wed, 13 Mar 2002 08:49:18 +0100
"Luis Alberto Amigo Navarro" <lamigo@atc.unican.es>
Re: bad performance on irix
part of postgres.conf

fsync on
wal_files=6
wal_buffers=64
shared_buffers=81940
sort_mem=16384
checkpoint segments=10


thanks and regards


Wed, 13 Mar 2002 09:01:13 +0100
"Luis Alberto Amigo Navarro" <lamigo@atc.unican.es>
Re: bad performance on irix
lamigo@atc.unican.es ("Luis Alberto Amigo Navarro") writes:

 > we're running on sgi powerchallenge, 8 r10000 4-way smp, and we're
 > getting bad performance from postgres, throughput increases from 1
 > to 5 streams, but from 5 and above there is no further increase,
 > performance analysis show high sleep waiting for resources

IIRC there is a bottleneck on calls to sleep() or similar on IRIX
SMP.  All requests are dealt with on just one of the CPUs.  I don't
recollect whether there is a way to work around that or whether
programs need to be rewritten.
-- 
Pete Forman                -./\.-  Disclaimer: This post is originated
WesternGeco                  -./\.-   by myself and does not represent
pete.forman@westerngeco.com    -./\.-   opinion of Schlumberger, Baker
http://petef.port5.com  (new)    -./\.-   Hughes or their divisions.

25 Mar 2002 15:04:04 +0000
Pete Forman <pete.forman@westerngeco.com>
Re: bad performance on irix