Re: CPU upgrade caused application slow down

From: Tim Gorman <tim_at_sagelogix.com>
Date: Fri, 30 Apr 2004 04:12:12 -0600
Message-ID: <BCB7829C.14183%tim@sagelogix.com>

Zhu Chao,

Sustained rates of 15-20 Mbytes/sec is absolute network saturation if you'r= e
running 100BaseT - don=B9t forget that 100 Mbits/sec is 12.5 Mbytes/sec. Eve= n
if the network segment closest to the server is GigE, you might have a network segment somewhere in the mix running at 100BaseT, perhaps?

Cary's remarks aren't theory, of course. Making one component of the stack of technology much faster will almost certainly cause a bottleneck in another component. Think of a 10-mile (16 km) roadway where the first 6 miles (10 km) are expanded to 4 lanes while the remainder is left at 2 lanes. That was the situation in my hometown (Evergreen, Colorado) some years ago -- guess whether the roadway expansion helped improve traffic flo= w
or caused massive backups where the lanes reduced from 4 to 2...?

Just some thoughts...

-Tim

> 1.. According to Cary Millsap=A1=AFs theory, upgrade CPU *CAN* make performan=
ce
> worse. In his case, SQL*Net was the bottleneck. Our server network traffi=
c is
> only at 15-20Mb/Second. This seems not like the bottleneck, Though from 1=
0046
> trace report, sqlnet wait is the NO.1 wait event, but this is normal for =
most
> applications. I also tried to change the tnsnames.ora and listener.ora w=
ith
> larger SDU/TDU of 8KB, restarted tuxedo service and oracle listener. And
> compare the performance data leter. This does not make much difference fo=
r
> application response time.

>=20

> 2.. We did some pure simple SQL test. Result in appendix 1. SAME SQL in
> 1200MHZ CPU does run faster.

>=20

> 2.. We write a simple tuxedo service run the same SQL for 1000 times.
> Everytime the SQL is transferred through SQL*Net and result is fetched in=
to
> host variable. The result still shows that it runs faster on 1200MHZ CPU.=
The
> average response time in 1200MHZ server is 12.12ms ,and the average respo=
nse
> time in 900mhz server is 14.20ms.

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Received on Fri Apr 30 2004 - 05:08:25 CDT