From: Charles Oliver Nutter <charles.nutter@...>
Date: 2007-12-22T23:31:56+09:00
Subject: Re: Experimental PATCH to improve thread performance

Brent Roman wrote:
> 
> Charles Oliver Nutter-2 wrote:
>>
>> I'd love to know what broke in JRuby. I tried both benchmarks and 
>> they're very snappy on my machine. We're making a big push to get JRuby 
>> threading solid, so please let us know what you've seen.
>>
>>
> 
> I'd like to work with you on this after the holidays.
> In the meantime, I've attached a java backtrace
> of the failure in our dreaded "killer app"
> Let me know if you can glean anything from it that will
> help me create a simple test case for you.
> 
> http://www.nabble.com/file/p14467248/jruby-1.1b1.backtrace
> jruby-1.1b1.backtrace 

The bug here is that for some reason "self" is null going into a call. 
There have been various issues in JRuby that could cause that, all 
concurrency related, all fixed. One example is regexp caching; the code 
that compiled and cached a regexp on first encounter wasn't thread safe, 
resulting in some threads trying to invoke against a null regexp object 
or pass a null regexp object as a parameter. That has been fixed, and to 
my knowledge there are no existing threading bugs that would fail in 
this way (though it's certainly possible you've found a new one).

I don't expect this would be hard to fix if we cooperated a bit.

- Charlie