Re: thread priorities?

[<don...@is...>]

 > As of now - no. There is no way to specify or change threads priorities.
 > There are several caveats:
 > 1. We have to unify what priority means across platforms. On Win32 we
 > have just SetThreadPriority...

So far I don't know what exactly all of these things do.
But I guess the best that can be done is use what the platform
provides and put a short description and a link in the clisp doc.

 > 2. On Linux in order process to be allowed to change scheduling
 > policy/priority of thread it needs CAP_SYS_NICE capability
 > (http://linux.die.net/man/7/capabilities). By default it is available
 > only to privileged (root) processes. So if you just download/build
 > clisp and run it as non-root you will not be able to change the
 > priority.

I'd have expected that you start a process with a given priority
(and perhaps can change that from outside the process), and then
within the process you can set thread priorities up to the process
priority.

 > 3. IMO, generally playing with threads priorities is bad idea. There
 > are very few cases where it makes sense (e.g. communication with
 > devices when protocol timing is important). Also note that garbage
 > collection is "stop-the-world" i.e. all threads are suspended during
 > GC.

Yes, I see that GC is a concern.  I'd expect this to run in the
process (highest available) priority.

What I really wanted to do was start a separate thread to do a long
computation and LOWER its priority.
What I was observing is that my machine would become unresponsive 
during occasional data dumps.

 > I am not against implementing it but i would set the task with low
 > priority :).

I was imagining that it would at least be easy to do.