Path: utzoo!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!tut.cis.ohio-state.edu!sei.cmu.edu!fs7.ece.cmu.edu!o.gp.cs.cmu.edu!netnews From: af@cs.cmu.edu (Alessandro Forin) Newsgroups: comp.os.mach Subject: The value of microbenchmarking (WAS Re: Mach RPC Throughput...) Message-ID: <1991Mar18.155406.1320@cs.cmu.edu> Date: 18 Mar 91 15:54:06 GMT References: <63274@bbn.BBN.COM> <9337@star.cs.vu.nl> Sender: netnews@cs.cmu.edu (USENET News Group Software) Followup-To: comp.os.mach Organization: School of Computer Science, Carnegie Mellon Lines: 43 In article <9337@star.cs.vu.nl>, ast@cs.vu.nl (Andy Tanenbaum) writes: > > What are the current figures for the 3.0 microkernel for sending a null > message from user space on one machine over the Ethernet to another > user process and then back, i.e. the null RPC time? Also, what is the > maximum user-to-user bandwidth in 3.0? If possibly, what are they > on Sun 3/60s, to compare them with the numbers I published in the Dec, 1990 > CACM. > > Andy Tanenbaum (ast@cs.vu.nl) It is customary in our field to use microbenchmarks such as ast's one when talking about a system, for various (practical) reasons. However, that is only meaningful for comparisons purposes when all other things are equal. In this case I strongly fear we are comparing apples and oranges. I was, for instance, surprised to hear from a friend that visited Denmark last summer that Amoeba is quite far from being a usable system. Certainly things have improved since, but I will only be willing to compare Mach and Amoeba seriously when I will be able to: 1) login from testarossa.mach.cs.cmu.edu to a machine running Amoeba 2) compile a C program, maybe run some Lisp code 3) send/receive mail locally 4) locally produce a paper describing my impressions of the system 5) come back a couple weeks later and find all my files still there I can certainly volunteer to ast an account on testarossa which has been a Mach 3.0 system for quite some time, to prove that it meets all the above criteria. [A quick way to summarize the above tests is to answer the question "Does Andy Tanenbaum use Amoeba as his own operating system ?".] Please note that Sprite and the V kernel both pass, as far as I know, the above tests. In addition, I have a Sprite distribution tape that I received at no charge and installed myself on my machine, but that's a story for another day... Respectfully yours, sandro- PS: Incidentally, does the "local RPC" optimization take into account heterogeneity ? I mean, what are the times between a Sun 3/60 and a VaxStation 3100. Just curious.