[concurrency-interest] missed deadlines.

Dhanji R. Prasanna dhanji at gmail.com
Thu Jul 6 23:45:07 EDT 2006


On 7/7/06, David Holmes <dcholmes at optusnet.com.au> wrote:
>
> Dhanji R. Prasanna writes:
> > Re auto-creation of pools, what is wrong with simply starting out with
> the
> > max-intended size? After all there is no cost associated with idle
> threads
> is
> > there?
>
> Sure there is - they use up OS threads, stack space etc. If they didn't we
> wouldn't need thread pools we would just keep as many idle threads as we
> wanted.


Surely the cost of starting new threads (and killing excess idle ones) is
greater than the cost of keeping a reasonable number of idle threads around?
perhaps I should have rephrased "no cost" to "comparatively less cost".


> Having an unbounded maximum number of threads can be a bad idea if you
> have
> an unbounded potential arrival rate for tasks. If the task arrival rate is
> limited then so is the thread creation rate.


 Yea, I cant think of when an unbounded max # of threads is ever a good
idea? Even at OS-level semantics...

ScheduledThreadPoolExecutor sets up the ThreadPoolExecutor queueing and
> threading behaviour is a very specific way: the queue is effectively
> unbounded so only coreSize comes into play. Given that, there is less
> control over how ScheduledThreadPoolExecutor behaves.


This is how I read it STPE is a specialization of TPE. Peter made a fair
comment to me, that perhaps STPE should have embedded/delegated to TPE
rather than extended from it (to avoid contract confusion).
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