RE: Saving the System i: Fight Rather Than Switch

I'd guess the problem isn't with Websphere, but instead with the OS and
hardware architecture (NUMA vs. SMP).

Since all threads run under the same process, the OS was probably trying
not to split threads between processors.

By chance, do you remember what hardware and OS was being used?

Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121
  

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx 
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Nathan Andelin
Sent: Wednesday, December 13, 2006 5:17 PM
To: Midrange Systems Technical Discussion
Subject: Re: Saving the System i: Fight Rather Than Switch

Walden Leverich wrote:
Are you saying WebSphere won't take advantage
of multiple processors?

My comment about needing 32 instances of Websphere to utilize 
a 16-way server was based on a  case study I downloaded from 
an IBM Web site a few years ago, featuring an application 
that was deployed across 64 instances of Websphere, running 
on a 32-way server.

In the beginning, they tried deploying the application under 
a few instances of Websphere - setting the thread count as 
high as possible.  Throughput was horrible while most of the 
CPU's remained idle under that approach.  Reducing the thread 
count and running more instances of the application server 
was their final attempt at making it scale.

Of course, you can't use any one particular case study as a 
benchmark for every workload, but my impression was that 
Websphere application server itself was the bottleneck, which 
is counter intuitive.  Threaded applications should 
theoretically spread their workloads across all processors.

I read something similar about ASP .Net architecture, where 
companies were deploying applications under out of process 
servers, with each server hosting a separate instance of the 
Common Language Runtime, which in my mind is comparable to 
running multiple instances of a Java Virtual Machine.

Nathan.







 
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