Re: I need help with RAM (I suspect a problem but ...)

Gerry S Hayes (sumner@CMU.EDU)
Sun, 16 Feb 1997 02:22:57 -0500 (EST)


"W. Reilly Cooley" <wcooley@navi.net> writes:
> I have found that with 32MB of memory running up to "make -j 30" or so
> (maybe higher, I gave up because I found little difference in the time
> for a kernel make with that than without it, and often it seemed to
> take several seconds _longer_ with more concurrent jobs, but I have
> only one CPU) I had no swapping (but I had nothing else running on the
> machine)

More than the "-j #" option is important here. RAM use will vary
radically depending on what parts of the kernel you are compiling.
-j 30 is excessive on a single processor machine, though; I find -j8
to be optimal on a PPro 180 with 64MB RAM. -j16 hits swap on this
machine with my standard kernel options. -j12 fails to hit swap but
is slower than -j8. I don't think that anyone else can get anything
useful from this except that they need to try timing things
themselves; -jX, where X is 4 times the number of processors in the
machine, is a good place to start for machines with 16MB+ of RAM.

Cordially,

Sumner

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