> >
> > Well, as far as I know the 2.0 series of kernels have a global lock
> > around all the kernel code wich effectively implies that only one
> > proccess could be in the kernel at the same time this is the so
> > called global lock. Now int the 2.1 and 2.2 series the kernel has
> > been moved to a fine grained lock wich implies that only one proccess
> > can be in the same locked kernel code, but the locked code is a
> > little part of the kernel, not the whole kernel, so the speed is
> > better.
> >
> > About the threads part; I don't really understand the NT's text (and
> > so other things about NT). It's true that the threads in linux are in
> > user space, but they are like any other proccess and the time is
> > divided by the scheduler, not by the app. If a program spawns two
> > threads there will be (if I remember correctly) a total of four
> > processes two for the threads, + one for the program + one for a
> > thread spawned by linuxthreads in glibc which controls the signals
> > and locks between the threads, this "control thread" is closed
> > automatically when all the other threads have finished.
>
>
> I don't understand the "user-space" point. Threads on linux are
> _kernel_ threads... they are distinct 'processes' in every sense of
> the word, each having its own context (proc structure as it is known
> in most unix circles). Some machines do this in userspace, where
> there is one kernel process and some library code actually interlaces
> execution of each user thread onto that one (or more if specified)
> kernel threads. If you run 10 threads, you get 11 processes, one of
> them to manage the 10 actual threads running. IE I always see only
> N+1 processes on my machines when running N thread applications.
>
> Perhaps part of this is a terminology problem, (user space vs
> kernel space)??
>
>
Yes, I say user space because the kernel does not distiguish betwen
threads a processes, a thread has it's own PID and it works like any
other independent process. (I was wrong with that terminology)
And to the number of threads I say a program wich does two
pthread_create will end having a PID for the program itself, a PID
for the thread manager, and a PID for every thread, for a total of
four different PIDs.
\_/, _
| @___oo ( Jorge Nerin
/\ /\ / (___,,,}_--~
) /^\) ^\/ _) ~__ [EMAIL PROTECTED]
) /^\/ _) (_
) _ / / _) ( [EMAIL PROTECTED]
/\ )/\/ || | )_)
< > |(,,) )__)
|| / \)___)\
| \____( )___) )___
\______(_______;;; __;;;
Greeetings from Zaragoza (Spain)
-
Linux SMP list: FIRST see FAQ at http://www.irisa.fr/prive/mentre/smp-faq/
To Unsubscribe: send "unsubscribe linux-smp" to [EMAIL PROTECTED]
