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Re: Extra systems in world load
In article <19891031210329.1.BARMAR@OCCAM.THINK.COM> barmar@THINK.COM (Barry Margolin) writes:
> Date: Mon, 30 Oct 89 09:37:00 MST
> From: firstname.lastname@example.org (David R. Strip)
> What are the disadvantages of adding a large, infrequently used
> system (e.g., Macsyma) to a world load (on a 3645, to be
> precise)? Presumably this increases boot time, but does it
> have other nasty performance hits once it has been ignored for
> a long time?
>It will increase the size of the world load on disk, and slightly
>increase the boot time, but it shouldn't have much effect on runtime
>performance. Programs that aren't used will just sit on disk, waiting
>to be paged in.
I can think of a couple of cases where doing this would increase
response time for a developer. These are:
1) Doing package DWIM
2) Doing List Callers
In both these cases, the presence of a package with many symbols
will probably cause a significantly longer response time. I don't
know a lot about how symbols are implemented but I assume there
is a separate hash-table for each package and that the above
functionalities involve paging the hash-table for each package.
BTW, I've wondered for several years if one could effectively "unload"
software by doing a remob on all the symbols in a package.
If the number of symbols is large and many of them are functions,
would there be a significant recovery of free space?
(responsible-p ADS message)