Re: [boost] [thread] throw during new boost::thread() ??

Subject: Re: [boost] [thread] throw during new boost::thread() ??
From: David M. Cotter (me_at_[hidden])
Date: 2010-08-21 19:21:06

>> these threads live a very short time and only maybe ten max are
>> alive at any one time.
>> 
>> for example if i'm iterating over every song in my music library and
>> doing some quick process, after about 5500 songs, the program stops
>> working.
>> 
>> i'm exiting the threads normally, so housekeeping is performed (tho
>> it would be performed anyway, right?)
>> 
>> i checked and when it crashes there are indeed only about five
>> threads running.  so SOME resource is not getting released, it's not
>> my resource, it's something to do with boost::threads.
> 
> Well, if things are *really* borked when it crashes, you might not be
> getting an accurate count of the running threads, or perhaps they've
> all exited by the time you actually check.  No matter how quick the
> task, without something to keep the number of actual simultaneous
> threads under control, you *are* very likely launching all 5500 of
> them at once in a way that—at best—will never perform well.

well, things aren't borked, i can assure you that no more than ten are running at once

during my test, i increment a "live" count and a "done" count, and they never differ by more than say five.  if they do, i assert.
so it's simply not possible that more than five are live at once.

put another way, i have a live thread count that in inc's when a thread is created and dec's when a thread is destroyed.  and that count never goes over five.

performance has never been an issue.  in my actual app i'm not actually just performing a tight loop spawning threads.  there's a lot happening between spawnings and threads close at the same rate they are opened.   again i've never had more than about five open at once.