Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!uwm.edu!bionet!ig!arizona!bakken From: bakken@cs.arizona.edu (Dave Bakken) Newsgroups: comp.sys.sequent Subject: Re: timing parallel programs Message-ID: <18356@megaron.cs.arizona.edu> Date: 26 Feb 90 22:32:35 GMT References: <1324@csisles.Bristol.AC.UK> <1803@baird.cs.strath.ac.uk> <11171@encore.Encore.COM> <67411@aerospace.AERO.ORG> <2151@baird.cs.strath.ac.uk> Reply-To: bakken@megaron.cs.arizona.edu (Dave Bakken) Organization: U of Arizona CS Dept, Tucson Lines: 30 In article <2151@baird.cs.strath.ac.uk> jim@cs.strath.ac.uk writes: >Yes, but that is not much help to the person who posed the initial >question. They were looking for a way to *exclusively* dedicate a >processor (or bunch of processors) to a particular process. The >tmp_affinity() system call does not provide this facility. It can bind >a process to a particular processor, but does not prevent another >process from also being bound to that processor or for the processor to >be given over to interrupt servicing and related kernel processing. If >the processor had to switch from the process that was being timed, the >benchmark results would be inconsistent and possibly non-reproducible. >I understand that Encore provide this capability on their boxes, so maybe >DYNIX will get it some day. I hope so, but I won't hold my breath, since Sequent seems to be about 2-3 years behind every other multiprocessor vendor in terms of their OS. I think that, in general, it would be nice to have a (privileged) system call that allowed you to dedicate a certain number of processors to a certain job without rebooting or anything. Even more generally, I think it would be useful to a lot of people of you could create separate pools of processors, where processors in the same pool pulled processes off of the same ready queue, and where you can configure which jobs go to which pool in a flexible way, maybe based on some sort of grouping (e.g., faculty, grad_student, undergrad). This grouping could probably be both static and dynamic. -- Dave Bakken Internet: bakken@cs.arizona.edu 721 Gould-Simpson Bldg UUCP: uunet!arizona!bakken Dept of Computer Science; U of Arizona Phone: +1 602 621 8372 (w) Tucson, AZ 85721 USA FAX: +1 602 621 4246