Re: ADA os talk

[Ian0Kerr@my-deja.com (Ian)]

"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