Re: load testing
Re: load testing
- Subject: Re: load testing
- From: Chuck Hill <email@hidden>
- Date: Tue, 26 Jul 2005 10:02:01 -0700
A week later... :-)
On Jul 21, 2005, at 3:34 PM, Mike Schrag wrote:
So I've been load testing my app w/ Apache JMeter while profiling
it with JProfiler, both really cool apps that are working really
nicely together -- just a public service announcement to start
things off.
So single "user" things were great ... Then I tossed 50 concurrent
"users" at it and things didn't go so well. CPU usage was
relatively low, memory was no problem at all, so obviously I'm
thinking lock contention. So I attach JProfiler and sure enough my
app is spending a HUGE amount of time (like >30%) in
sharedEditingContext.unlock(). Odd because I don't actually use
shared editing context. So for grins I added
EOSharedEditingContext.setDefaultSharedEditingContext(null) to the
top of my app and performance was around 10x faster.
So my three part question:
1) does the original behavior sound odd? it sure SEEMS odd to me
-- particularly since nobody else has mentioned this ... which
leads me to believe it's my fault ... which is historically a safe
bet to make when it comes to Me vs WO
Yes, this seems odd to me too. Was your load testing resulting in
more concurrent saveChanges() calls than the app would really
encounter? I've never timed this with and without the shared EC. It
could be that nobody else has either. Perhaps I can get a huge
performance boost!
2) what horrors will i bring upon my family by completely removing
the shared editing context ... my tests have not revealed a problem
yet, but i don't want to set myself up for trouble
If you are not using it then there is no need for it.
3) is there a better fix for whatever it is I am seeing with this
lock contention, or if nobody is seeing this issue, I'll go back to
the profiler drawing board and see if i can track down more
specifically where the contention is coming from
If you have not found out anything else you should file this on
http://bugreport.apple.com
Chuck
--
Practical WebObjects - a book for intermediate WebObjects developers
who want to increase their overall knowledge of WebObjects, or those
who are trying to solve specific application development problems.
http://www.global-village.net/products/practical_webobjects
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