domo@riddle.UUCP (Dominic Dunlop) (03/22/89)
In article <36715@bbn.COM> ellard@BBN.COM (Dan Ellard) writes: >Has anyone ever done any testing to measure the percentage >of time the UNIX kernel spends handling interrupts (i.e. in the interrupt >context), or in context switching for moderately loaded systems? Firstly, /usr/group's technical committee has a working group concerned with performance measurement. I'm sorry to say that I can't put my hands on an email address for a contact person. Can somebody in netland please post one? Although those who attend (typically bimonthly) meetings get the most out of these working groups, some have associated mailing lists which aid participation by those who cannot attend. Again, I don't know if this is the case with performance measurement. Clarification please, somebody? Secondly, well, there I was thumbing through AT&T Technical Journal, Vol 67 #5 (Sept-Oct 88) yesterday (I was waiting for a thirty-one page fax to arrive, but that's another story). In it I found An Analytical Model for UNIX Systems Gopalakrishnan Ramamurthy ``This paper presents an analytical model for a single-processor interactive computer system running under the UNIX operating system. The model is a closed multichain, multiclass priority-queueing network model. The model solution is an approximation and is based on mean value analysis. The validity of the model has been established by using it with a number of workloads and workload mixes and with a number of different computer systems. mean response times predicted by the model are within 10 percent of measured values. The model can be extended to tightly-coupled multiprocessor systems and multiple UNIX systems running with network file systems over local-area networks.'' and also A Performance Study of the UNIX System V Fork System Call using Casper Ronald E Barkley and Curt F Schimmel ``In this paper, we describe a general-purpose timing and tracing package, called CASPER, for UNIX System V. We also present the results of a study of the behaviour of the UNIX System V fork system call using this package. CASPER is designed to support high-resolution timing and tracing of software under UNIX System V. With CASPER, we were able to obtain detailed and accurate information on the behavoiur of the fork system call, which led to minor algorithmic changes that reduced the time to execute small forks by about 15 percent.'' > >I'm mostly interested in data about BSD-flavored UNIX or MACH, but >info about any other flavor of UNIX or other operating systems like >VAX/VMS, OS/360, MULTICS, etc. would be useful too. These papers are specifically about UNIX System V release 2 (Ramamurthy) and release 3 (Barkley & Schimmel). The latter paper cites CASPER the Friendy Daemon R E Barkley, D Chien Proceedings of the 1988 Summer Usenix Conference which might also be worth a look (must get around to ordering a copy of those proceedings). The math in the Ramamurthy paper, although not extensive, is not for amateurs (I'm definitely an amateur in this context); readers of the Barkley & Schimmel paper would benefit from having access to System V, release 3 source code (I don't). Sales message: I'd say that the AT&T Technical Journal is well worth $40 per year (US) or $50 per year (foreign), although potential subscribers should be warned that it covers all manner of technical topics (telecommunications, materials science, economics, human factors...), not just UNIX. The subscription address is AT&T Bell Laboratories Circulation Group, Room 1K-424, 101 J F Kennedy Parkway, Short Hills, NJ 07078. (Disclaimer: I am not assocated with \*(oR other than as \*(rE...) -- Dominic Dunlop domo@sphinx.co.uk domo@riddle.uucp