Mauricio Fernandez wrote:
> On Fri, Aug 18, 2006 at 06:05:12AM +0900, John Lam wrote:
>> I was wondering if anyone had taken a look at what % of time that ruby
>> spends doing method dispatch?
>>
>> I'll eventually do the experiments myself, but I wanted to check with
>> y'all to see if someone had already done some investigations. It would
>> be an interesting experiment to see how much you can improve method
>> dispatch performance by caching the reference to the method call
>> target, and invalidating it when the call context changes.
> 
> The current implementation has a method cache whose hit rate is above 95% or
> so (don't remember the exact figure; it's not hard to reproduce anyway) ---
> full method lookups are relatively rare.
> 
> Method dispatching is still fairly slow, though; I once measured that it took
> some ~200 instructions to run a CFUNC, and about half as much with YARV.
> Last time I read YARV's sources, it didn't have inline method caches (but it
> was caching constants, IIRC), but it's been a while and they might have been
> implemented meanwhile.
> 
I'm about to re-post my profiling of Ruby on a moderate-sized "Matrix"
benchmark. I'll post the link as soon as I get it re-run.