From: Kent Sibilev <ksruby@...>
Date: 2006-09-05T04:37:23+09:00
Subject: Re: The real difference between Mutex and Sync

This patch will make Mutex a bit slower, but much better in terms of
garbage collection:

Index: lib/thread.rb
===================================================================
RCS file: /src/ruby/lib/thread.rb,v
retrieving revision 1.16.2.2
diff -r1.16.2.2 thread.rb
99c99
<       @waiting.push Thread.current
---
>       @waiting.unshift Thread.current
115c115
<       t = @waiting.shift
---
>       t = @waiting.pop


On 9/4/06, Kent Sibilev <ksruby@gmail.com> wrote:
> On 9/4/06, Kent Sibilev <ksruby@gmail.com> wrote:
> > On 9/4/06, khaines@enigo.com <khaines@enigo.com> wrote:
> > >
> > > array.c's behavior is what needs to be examined in greater detail, here.
> > > Mutex, itself, is not doing anything surprising.
> > >
> > >
> > > Kirk Haines
> > >
> >
> > Good findings.
> >
> > I think the problem lies in the Array#shift (rb_ary_shift)
> > implementation. Basically, it just increments the internal pointer and
> > it never modifies the size of an array. This means that if you have an
> > array with 1000 elements and you 'shift' it 999 times, all these
> > elements are still visible to the garbage collector, until you modify
> > this array by triggering rb_ary_store method, for example.
> >
>
> I meant that rb_ary_shift never modifies the size of allocated memory.
>
> --
> Kent
> ---
> http://www.datanoise.com
>
>


-- 
Kent
---
http://www.datanoise.com