cooperative versus preempt
Wed, 23 Aug 1995 15:53:47 -0700 (PDT)
On Wed, 23 Aug 1995, Frank DiCostanzo wrote:
> it would seem a few major issues about this are being ignored:
> 1. wouldn't it be easier to exploit multiple processor architectures and
> distributed computing under preemptive threading? is tunes a single
> processor OS, end of story?
No, because MP is an issue related to contol _delivery_, not control
return. preemption vs. cooperation deals only with control return (to
> 2. as more and more OS's use threading, the hardware people will come
> around and implement threading in the processor. state changes and
> object protection won't take any noticable time at all. it happened with
> floating point and memory management, its only a matter of time for
> threading. (and hopefully garbage collection)
Two things. First of all, threading is the same as multitasking-- no
real difference, except the overhead.
Second, nothing is without a cost. If they implement threading in
hardware it will cost, just as it costs to rum memory management in
> 3. who really cares if a percentage of time is spent dealing with
> threading? as someone posted earlier, one can just wait a year and
> processors will double in speed.
Wow, will mine do that too? Last I checked, time increases entropy, not
decreases it. :)
Seriously, though, TUNES cannot be designed to run ONLY on the
cutting-edge models. I woud have NO objection to using ONLY preemption
on those cutting edge models, though-- if it had no other cost, it
certainly is nice to program for.
> 4. real time computing requires preemptive scheduling.
> Frank DiCostanzo