Paging Performance

[Brad Miller <miller@doughnut.cs.rochester.edu>]

As I sit here, editing something because my machine is too sluggish running a
compile and a dynamic GC to do anything else... I wonder:

I'm running on a 3620: the maxstor (sp?) disks are notorious for being slow. I
recall reading something in the internals doc under the schedular that page
faults do not generate sequence breaks. That is, when GC, for example, asks
for a page from disk, the processor does not go to another runnable process
(e.g. the compiler, the editor): it just waits for the page to come in. <my
understanding of the doc, please correct me if I'm wrong>.

I wonder if some wizard could enlighten me: isn't that a big waste of
processor resource, esp. with GCs going on? I'd think those cycles could be
put to better use... it certainly seems like *I* could be using them right
now! I understand <part of> the trade off here: certain parts of the system
might have to be moved to memory that cannot be paged, e.g. the schedular.
Since the minimum system is 8mb, I'd think there would be space, and the
overall performance improvement would be worth it. I know this may not come up
if you always tend to do *one* thing at a time: but the lispm environment
makes saving state so easy I tend to do lots of different things at once -
giving my poor machine's <paging> disks a workout!!

Thanks,
Brad Miller

PS to CWH@Fuji: <You didn't give me a mail address I could reply to> Thanks!!!
>much< more than I expected!
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miller@cs.rochester.edu {...[allegra|seismo]!rochester!miller}
Brad Miller
University of Rochester Computer Science Department