From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,LOTS_OF_MONEY
	autolearn=ham autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,5bcf30769d6d9599
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2001-09-03 03:01:54 PST
Path: archiver1.google.com!postnews1.google.com!not-for-mail
From: Ian0Kerr@my-deja.com (Ian)
Newsgroups: comp.lang.ada
Subject: Re: ADA os talk
Date: 3 Sep 2001 03:01:54 -0700
Organization: http://groups.google.com/
Message-ID: <eb48e9c0.0109030201.3954b0dc@posting.google.com>
References: <mailman.998888394.11895.comp.lang.ada@ada.eu.org>
 <20010829113230.0ae3febd.tonygair@blueyonder.co.uk>
 <9miteo$t7r$1@nh.pace.co.uk>
 <4twk7.28692$wX5.3722280@news6-win.server.ntlworld.com>
NNTP-Posting-Host: 194.133.99.210
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
X-Trace: posting.google.com 999511314 30760 127.0.0.1 (3 Sep 2001 10:01:54
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: 3 Sep 2001 10:01:54 GMT
Xref: archiver1.google.com comp.lang.ada:12650
Date: 2001-09-03T10:01:54+00:00
List-Id: <comp.lang.ada>

"chris.danx" <chris.danx@ntlworld.com> wrote in message news:<4twk7.28692$wX5.3722280@news6-win.server.ntlworld.com>...
> On x86 this is ok for monolithic kernels but if it's real privileged mode in
> a microkernel, then performance will take a hit.  If you fake privileged
> mode and run things in "user mode" with a user level IPC, then the hit will
> be much less.  Check out L4 for info on it.  Note that on other systems, the
> hit of the context switch (which are more frequent in microkernels) is not
> so bad and this scheme may not be necessary.
 
 
> Chris

Out of curiosity I looked up some context switching timings in case
this is an Intel 86k problem.

I have this data for a LynxOS 3.0.1 benchmark (supplied by the
manufacturer):

MPC604e         400 CPU clock cycles
MPC750          466  "     "     "
Pentium II      666  "     "     "
MC68060        1050  "     "     "
microSPARC II  3485  "     "     "

Just divide the cycles by the clock frequency to get timings. The
original data was for timings on different clock speeds and so did not
give a true comparison.

Q: why is the thread title not "Ada OS talk"?

Ian