386 malloc with huge programs
amy snader
amys at sco.COM
Sun Jul 24 04:45:00 AEST 1988
Here's a hint for all of you out there who are running
BIG programs on the '386, especially those large enough
to cause the system to page:
If your huge application does many small malloc()'s
(as opposed to a couple of big malloc()'s, compiling
your application with -lmalloc can be a tremendous
performance win.
This is a "try it and see" sort of thing.
For both small applications and for big applications that
allocate their memory all in one chunk,
normal malloc is less overhead.
But when -lmalloc wins, it really wins. I have an
(admittedly contrived) test program that runs in 1/50th
the time with -lmalloc.
The explanation has to do with which pages have to be
faulted in to manage malloc()'s freelist. I suspect
this may be helpful in running pathalias on the 386.
(To JFH -- no, there is no difference
in how a growing process is paged vs. one whose size
is static).
--Amy (sco!abs)
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