Re: [Xen-users] Re: Java non-performant in a domU?

Javier Guerra
Mon, 05 Jun 2006 05:14:55 -0000

On Sunday 04 June 2006 10:53 pm, Matthew Palmer wrote:
> That''s the crazy thing -- we''ve been monitoring
everything we can, and we
> can''t find any anomalous bottlenecks.  The application is
naturally CPU

just a wild guess, but on a heavily multithreaded and multiprocessor system
like yours, its quite possible that a given JVM could use a non-optimal
strategy on a Xen system.  I think it''s important to test different
JVM''s,
and different ''bitness'' of them (64bit vs. 32bit). Since 32bit
x86 is _SO_
register-starved, and Xen interferes with the infamous TLS trick, you should
try to use a 64bit clean system.  since you already stated that your software
can''t run on a 64bit JVM, maybe you could get some insight by running a
benchmark with similar threading and processor requirements, on all
combinations of 32bit, 64bit, Xen and non-Xen.

in the worst case, you might find that you must delay the Xen deployment until
your software gets more 64bit-friendly.  or maybe you''ll find that
simply
changing JVM get''s you the lost performance.

--
Javier