Subj : Re: Can I have more than one runtime to facilitate multiple threads?
To   : netscape.public.mozilla.jseng
From : Brendan Eich <brendan@meer.net>
Date : Tue Jul 01 2003 03:01 pm

David Bradley wrote:

> Consider, that if each thread's job is to process a JavaScript script. 
> And the system only has 4 cpu's, then having more than 4 or so will only 
> add to overhead, unless those scripts involve I/O. In that case, maybe 
> two times the cpu count is better. A lot hinges on the exact nature of 
> your system how much I/O vs CPU process is being done.

Amdahl's law says that if 1/3rd of the program is serial, you can't 
speed up the program with more than 3 processors; etc. for 1/4 and 4 
CPUs.  It sounds like blocking i/o is involved (JS_SuspendRequest and 
JS_ResumeRequest), and enough of it that the suspend/resume contention 
for rt->gcLock seemed high (although it wasn't clear to me that that was 
more than a hunch).

So yeah, it could be that there are simply too many threads being used 
here for the given target machine (which could be a uniprocessor).

/be

.