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From: georgeb@fai.UUCP (George Bosworth)
Newsgroups: comp.os.mach
Subject: Mach 3.0 Performance
Message-ID: <3102@fai.UUCP>
Date: 24 Jun 91 20:15:37 GMT
Reply-To: georgeb@fai.com (George Bosworth)
Lines: 47

In an article in the ASPLOS-IV Proceedings (full citation later),
researchers from U. of Washington published a side-by-side
performance comparison of Mach 2.5 and Mach 3.0.

They averaged three runs of seven diverse applications running on a
MIPS R3000-based DECstation 5000/200 with 24 MB of memory.  I condense
their tabulation of results by adding the applications together for
a few of their measured items:

   Measured Item                        Mach 2.5       Mach 3.0
   ==========================           ========       ========

   Elapsed time (seconds)                    307            416

   Address space context switches         10,740        215,811

   Kernel-level thread context            18,255        248,274
     switches 

   System calls                           90,515        278,771

   Kernel mode TLB misses                439,067      3,867,602

Here are two questions:

1. The authors argue that RISC hardware and microkernel OS designs
   are out of kilter, and deliberately chose a RISC machine for
   the Mach comparisons.  Are there similar timing runs for Mach 2.5
   and Mach 3.0 on CISC machines?

2. Are there any reasons to believe that more current versions of
   Mach 3.0 have improved in performance? If so, are there published
   performance runs?

Full citation:  Thomas E. Anderson, Henry M. Levy, Brian N. Bershad,
and Edward D Lazowska, "The Interaction of Architecture and Operating
System Design", in Proceedings of the Fourth International Conference
on Architectural Support for Programming Languages and Operating
Systems, April 1991, pages 108-120.  The proceedings are available
from ACM by order number 556910.

George
  
George H. Bosworth                    georgeb@fai.com    or  
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