From: peter@ficc.uu.net (Peter da Silva)
Subject: Re: Ada vs C/UNIX / switching speeds
Date: 25 Nov 89 18:39:13 GMT [thread overview]
Message-ID: <7103@ficc.uu.net> (raw)
In-Reply-To: 14042@grebyn.com
> > The following article relates to the recent discussion
> > of Ada vs. UNIX/C and lightweight processes. Notice the
> > disastrous performance produced by UNIX/C relative to Ada.
Yeh. Since ADA shouldn't have to do more than a function call, a switch
in stack frames, and a return in the new stack frame... why is it so slow?
> >Sun 3/50 (UNIX) Function call ~ 0.01 ms
> >Sun 3/50 (UNIX) Verdix Ada tasks ~ 0.3 ms
> >Sun 3/50 (UNIX) UNIX/C processes ~10.0 ms
I would have expected the ADA task switch to take no more than 0.05 ms
based on the speed of a function call. There's no MMU to deal with, a not
inconsiderable overhead. There's no switch between user and kernel mode.
There's none of the overhead that UNIX has to deal with. What's it doing,
dynamically rearranging priorities at context-switch time instead of when
you make a call or handle an external event?
Lester Buck: could yo do some estimates on the context switch time for
your C-threads routines? And has anyone done any realtime benchmarks on
the Amiga?
--
`-_-' Peter da Silva <peter@ficc.uu.net> <peter@sugar.lonestar.org>.
'U` -------------- +1 713 274 5180.
"The basic notion underlying USENET is the flame."
-- Chuq Von Rospach, chuq@Apple.COM
next prev parent reply other threads:[~1989-11-25 18:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
1989-11-22 21:37 Ada vs C/UNIX / switching speeds Ted Holden
1989-11-23 8:30 ` Markku Sakkinen
1989-11-25 18:39 ` Peter da Silva [this message]
1989-11-27 16:39 ` Jonathan Shapiro
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