Re: performance problems

[Tom Tromey <tromey@cygnus.com>]

>>>>> "Jeff" == Jeff Sturm <jsturm@sigma6.com> writes:

Jeff> I compiled the benchmark code with -O3, I think...  I also
Jeff> hacked the GC initialization code to bump the initial heap up to
Jeff> 16MB.  I should probably send a patch for it.  Does anyone
Jeff> object to an environment variable, something like GCJ_HEAP_INIT,
Jeff> to set the initial heap size?

I'm not too thrilled with the idea of an environment variable.
Shouldn't this be set on a per-application basis?

Two ideas:

1. Change the default in the Boehm GC on a per-target basis.
   For native builds we could make it larger.

2. Add a new --heap-size option to gcj and build in the number
   at link time.  Change the GC interface (such as it is) in libgcj
   to support setting this at initialization time.

Comments?

I don't have time to implement either one :-(

Jeff> Any other thread trying to enter the monitor is going to
Jeff> busy-loop at least until the I/O completes, potentially a very
Jeff> long time.

This seems like a problem in LinuxThreads.  Busy-waiting is bad, and
there's no rule that says you should only hold a mutex for a short
period of time.

Tom