[fedora-java] Re: Performance issues with gcc-4.1.0-0.10.i386

[Andrew Haley]

Andrew Overholt writes:
 > 
 > I am seeing some performance issues with the latest gcc rawhide RPM set.
 > I tried a build of Eclipse with them and it took 650 minutes 42 seconds
 > where it used to take about 20 - 30 minutes (this is just for the
 > bytecode, BTW).  I watched the log a bit as it built but nothing stood
 > out to me as taking more time than anything else.
 > 
 > My build did eventually finish, however, so I upgraded to those Eclipse
 > RPMs and tried to run Eclipse.  Startup is very slow.  I used OProfile
 > to grab some data and put it here:
 > 
 > http://overholt.ca/eclipsestartup-opreport.txt
 > 
 > Then I reset OProfile and grabbed some data while using Eclipse for a
 > few minutes.  I have two small projects checked out and I cleaned them,
 > opened a file (which took a very long time), moved around a bit in the
 > file, closed it, and reopened it (which took much less time).  Here is
 > the report from that session:
 > 
 > http://overholt.ca/eclipseusage-opreport.txt
 > 
 > The top of both reports is similar.  Here's the top of the startup
 > report:
 > 
 > samples  %        app name                 symbol name
 > 1814289  28.7922  libgcc_s-4.1.0-20051221.so.1 __deregister_frame_info_bases

This is usually called when a library is unloaded.  I can't imagine
any reason why this might happen when running gij.

The quickest way to find this is to run under gdb and see where
__deregister_frame_info_bases is called from.

I have seen this once, and it turned out to be a bug in our interface
with the garbage collector.  But as far as I am aware little has
changed since the last gcc build thath might affect this.

Andrew.