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Re: profile questions
- From: Andrew Haley <aph at gcc dot gnu dot org>
- To: Anthony Green <green at redhat dot com>
- Cc: java at gcc dot gnu dot org
- Date: Mon, 28 Aug 2006 10:29:42 +0100
- Subject: Re: profile questions
- References: <1156693205.2716.9.camel@localhost.localdomain>
Anthony Green writes:
> I just profiled tomcat's hello world servlet on i386 FC development.
>
> To do this, I just installed the following two packages...
> tomcat5-5.5.17-6jpp.1
> tomcat5-webapps-5.5.17-6jpp.1
> ...ran "service tomcat5 start", and then oprofiled while running...
> ab -n 20000 -c 160 http://172.31.0.50:8080/servlets-examples/servlet/HelloWorldExample
> (ab is part of the httpd package)
>
> I have all of appropriate gcc and tomcat debuginfo installed.
>
> See below for the top of "opreport -l".
>
> So, my questions...
> 1. What's with _dl_addr taking > 51% of the time?
This is because of the lamentable decision to generate line numbers
and filenames in all stack traces, by default. This causes jonas to
run at half speed too.
So, having these line numbers makes all app servers on gcj run at half
speed. What do I need to do to persuade people that line numbers
should be off by default?
> 2. What's with the messed up .so name for catalina?
It's not messed up; it's a copy of the library, because some class in
catalina-5.5.17.jar is loaded twice, by two different class loaders.
Andrew.