Date: Sun, 6 Mar 2005 00:40:44 -0800 From: steve@Watt.COM (Steve Watt) To: kamalp@acm.org Cc: hackers@freebsd.org Subject: Re: sched_4BSD Message-ID: <200503060840.j268eiPT004555@wattres.watt.com> In-Reply-To: <20050304032003.89305.qmail@web52702.mail.yahoo.com>
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[ Attempted to clean up citations, apologies if I mis-attribute something ] In article <20050304032003.89305.qmail@web52702.mail.yahoo.com>, Kamal R. Prasad <kamalp@acm.org> wrote: Kamal>--- Julian Elischer <julian@elischer.org> wrote: Julian> Kamal R. Prasad wrote: Kamal>>--- Julian Elischer <julian@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...
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