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dual core processor low performance

Rene Mendez_4
Super Advisor

dual core processor low performance

Hi

I migrate the rp8400 to rp8420 and install dual core processor. total 3 dualcore 6 cpus

But the databases performance is very low and exist performance problem.

Version Sybase 12.51
HPUX 11.11

Exists service notes the dualcore with hpux 11.11 or sybase with dual core.

Regards
Rene
6 REPLIES
Hein van den Heuvel
Honored Contributor

Re: dual core processor low performance

Did you have a reason to believe more processor cores would help your specific application? Was CPU time the limiting factor/bottleneck? Did you ask the system to do more? Was it already mostly waiting on disk/net/???

How many processors where there? How fast?
Are the new cores faster or slower or equal?

Did you scale the rest of the system with the increased capacity? More memory, More IO channels? More disks ?

If the application/sybase is single stream, then more CPUs will not help.

Was the prior system heavily cpu loaded?

Did you tell the application and/or Sybase that it is OK to use more CPUs?

Hope these questions get you thinking towards the root causes of the system performance. At the very least these question should suggest some datapoints to include in a more detailed problem statement.

Regards,

Hein van den Heuvel
HvdH Performance Consulting
Yogeeraj_1
Honored Contributor

Re: dual core processor low performance

Hi rene.

I don't have any experience on Sybase. See if you can identify any bottle necks at the database level.

At the OS level, you can use glance or measureware to plot performance graphs of your system and identify any problems

hope this helps too!

kind regards
yogeeraj
No person was ever honoured for what he received. Honour has been the reward for what he gave (clavin coolidge)
Rene Mendez_4
Super Advisor

Re: dual core processor low performance

Old processor: 8 x 875
New processor: 6 x 1.1 dual core

New Configuration: 6 cpu, 2 celda, 1 partition

Hein van den Heuvel
Honored Contributor

Re: dual core processor low performance

>> Old processor: 8 x 875
>> New processor: 6 x 1.1 dual core

Hmm, now I can confused.
Did you expect a perofmance improvement?

There seems to be very few performance numbers avaiable on those CPUs.
If we just take the Processor Speed (I know, I know...) times count, then the old system system would rate 7000, the new 6600. Now this is only an indication, but it suggest to me that you have less raw power.
And you have few streams to do work.

fwiw,
Hein.



Steve Lewis
Honored Contributor

Re: dual core processor low performance

We went from 12x875 to 8x1100 and performance is no different. The run queue is slightly higher and we saved on per-cpu licence costs but thats all.
The reason its no faster?
Firstly, with more cpus, data flows around the machine better with better distribution of work and less fighting over the cpu cache, with the parallelised processing that we have.
Secondly, if your system is i/o bound (and databases are i/o bound pretty much by definition) then you could run your DB on a supercomputer CPU and it won't make any difference to overall performance. Your system is stuck waiting for i/o.
I tried to explain this to my management and project board before our change, but they wouldn't have any of it. They thought the faster cpus would make the whole system faster. But they were wrong and I was right.

Steven E. Protter
Exalted Contributor

Re: dual core processor low performance

Shalom Rene,

A lot of people are surprised when faster performance is not obtained merely my having fast processers.

Note: i/o is more important than anything else with database apps. How the storage is configured, raid level is important. A heavy write db on raid 5 storage is a recipe for delays.

First, find the problem:
http://www.hpux.ws/system.perf.sh

Then we'll try and help you fix it.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com