Re: MMX for kernel

Theodore Y. Ts'o (tytso@MIT.EDU)
Fri, 7 Feb 1997 16:57:51 -0500

From: (Harald Koenig)
Date: Fri, 7 Feb 1997 15:06:28 +0100 (MET)

> If there were many, many proceses which used the FPU, one could imagine
> an advisory bit which meant "when task switching to this process,
> immediately restore my FPU registers, since I'm an intensive FPU
> user".

wouldn't only 2 FP-intensive (compute) processes be enough for this
scenario ?

Yes, if we're constantly switching between them.

The trick, of course, is figuring out when to turn on the advisory bit.
It would be rather lame if the program had to turn it on automatically.
One way might be to do lazy evaluation, and if the program uses takes
the floating point trap more than (say) 10 times, turn on the advisory
bit at that point.