Subj : Re: thread suspend using pthreads?
To   : comp.programming.threads
From : Joe Seigh
Date : Thu Sep 01 2005 09:12 am

Yaytay wrote:
> "Steve Watt" <steve@Watt.COM> wrote in message 
> news:df65m7$2g24$1@wattres.Watt.COM...
> 
>>So what is suspend/resume being used for in the application?
>>
>>There _are_ a few places where it's a useful feature.  They are
>>extremely rare.
> 
> 
> On Windows it is reasonably common practice to start a thread suspended, 
> then resume it.
> This does not introduce race conditions.
> So I'd argue that it is suspend that is risky, not resume.
> 

This is a way of dealing with the creation of threads being expensive
so you create them before you actually need them.  There are lots
of ways of dealing with that.  One is to use a condition variable or
semaphore that the created thread blocks on first thing.  You unblock
it when you want the thread to actually start.  Thread pools are a
generalization of this mechanism.  You prestart a bunch of threads
and start them when you want to.  You also can reuse the threads in
this case.

The other thing you can do when porting this code over is change
the thread create to a no-op and make the thread resume the actual
thread create (pthread_create).  This won't affect correctness, just
performance.  Is there an actual performance issue on thread creation
here?


-- 
Joe Seigh

When you get lemons, you make lemonade.
When you get hardware, you make software.

.