sched_4BSD

[Steve Watt]

[ Attempted to clean up citations, apologies if I mis-attribute
something ]

In article <20050304032003.89305.qmail at web52702.mail.yahoo.com>,
	Kamal R. Prasad <kamalp at acm.org> wrote:
Kamal>--- Julian Elischer <julian at elischer.org> wrote:
Julian> Kamal R. Prasad wrote:
Kamal>>--- Julian Elischer <julian at elischer.org> wrote:
Julian>>Kamal R. Prasad wrote:
Kamal>>>Maybe the freebsd implementation should implement
Kamal>>>NPTL in entirety.
Julian>>NPTL?
Julian>>New Pthreads Library from Library?

No, Native POSIX Threads Library for Linux.  It's a Linux
implementation of kernel-level threads that was spearheded by
Ulrich Drepper.  It fixes most (all?) of the ugly signal problems
that LinuxThreads had.

Kamal>>Yes.

Julian>>isn't that GPL'd?

Yes.

Kamal>No -it is a standard. The linux implementation of nptl
Kamal>is gpl'ed.

No, POSIX 1003.1 is the standard, the thread portion was known for
some time as 1003.1c, but was combined in with the base.

NPTL is a particular (less brain damaged than LinuxThreads)
implementation of the POSIX thread standard.

Likewise, scheduler activations are a decent implementation of
threads.  I'll refrain from commenting further about libc_r.

Julian> so how does that differ from what we have ... a
Julian> native pthreads library?

Kamal>I just said if it was conformant with NPTL, thread and
Kamal>process scheduling would co-exist.

Uh, as far as I understand, in NPTL, each thread gets a scheduler
slot, and it is my understanding that there is nothing to protect
against the issue that Julian is asking about (1000 threads of a
single process *do* get 1000 times the time slices).

Whether that is a bug or a feature depends very heavily on the
system load.


-- 
Steve Watt KD6GGD  PP-ASEL-IA          ICBM: 121W 56' 57.8" / 37N 20' 14.9"
 Internet: steve @ Watt.COM                         Whois: SW32
   Free time?  There's no such thing.  It just comes in varying prices...