[Vm-dev] Re: [Pharo-project] Waste of CPU Power by polling events?

[Eliot Miranda]

2011/1/11 Levente Uzonyi <leves at elte.hu>

>
> On Tue, 11 Jan 2011, Eliot Miranda wrote:
>
> (Pine can't quote your mail, sorry.)
>
> "The problem with linux is that the pthreads implementation doesn't allow a
> normal user-level process to create high-priroity threads so that as
> soon as the Vm starts to spin doing some computation the heartbeat thread
> is shut-out and if the spinning computation only interrupted when a delay
> expires it'll never get interrupted because it is blocking the very thread
> that would signal the delay.  So until linux's pthreads implementation
> supports multiple priorities we're stuck with hacks like the interval timer
> based itimer in the linux Cog VMs."
>
> What about keeping the priority of the heartbeat thread at user-level and
> decreasing the other VM threads' priority slighly?
>

Linux doesn't allow more than /one/ thread priority for threads in a
user-level process.   So one /can't/ have multiple priorities.  All threads
run at the same priority.  This is a horrible bug in the linux pthreads
implementation but there it is.

best
Eliot

>
>
> Levente
>
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