Julian Elischer wrote:
Sarath Kamisetty wrote:
Hi,

How does Linux handle this ? Any idea ?

If you make 1000 threads, you get 1000 slots on the scheduler. (last time I looked..
Let me know if I'm wrong).


The guy next to you with 'vi' gets 1 slot..
who gets more cpu?

And how is that different from forking 1000 processes and use shared memory to communicate? I'll tell you: the thread option will be better for every user in that machine, so let's promote threads.


IMHO, a thread should have the same privilege as a full processes, and it should count as a process for resource limits.




Thanks,
Sarat

On Mon, 28 Feb 2005 00:26:10 -0800, Julian Elischer <[EMAIL PROTECTED]> wrote:


Ashwin Chandra wrote:


I wanted to get some clarification about the 4BSD scheduler. I am sort of
confused why there are two forms of scheduling, one done between processes and
another done between threads in a process. The priority calculations seem to be
done only with processes and I assume that the global run queue holds processes,
not threads. Also why is there only 1 run queue for 1 CPU. What happens to
blocked processes and ready to be runned processes?

Part of the challenge of adding threads to a system is to make it hard for a
threaded process to "flood" the system run queues so that other processes
get no cpu time.


The scheme in the current freeBSD schedulers is a "crude" method, by which
only a limitted number of threads per process are allowed to be added to
the system run queue. RUnnable hreads fo r aprocess are kept on a run queue for
the process and only the highest N prioriy hreads are actually put on the
system run queue.


This is by no means the best way, but rather the
easiest way. I am hoping that some PhD candidate somewhere will decide
that thread scheduling is his topic and will figure out a better way
of doing this.

both run queues hold threads. This is still a place wjere a lot
of work can be done.

:-)




Ash
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