Re: VM benchmarks

["Martin J. Bligh" <mbligh@xxxxxxxxxxx>]

> It seems to me that increasing -jX doesn't necessarily result in a
> linear increase in load since the kernel build process has all kinds of
> dependencies and source files distributed in different nested
> subdirectories. Thus, it may not be possible for make to spawn X gcc
> instances say unless there are at least X independent files to compile
> in the directory it's working in. Maybe something about kbuild that I
> don't know, I just use make bzImage.

A full -j on the kernel spawns about 1300 processes constantly on a 16-way,
so there's not too much of a problem there. Make sure you do "make vmlinux"
not "make bzImage" though, as the compression phase is all single-threaded.
There's also a pretty much single-threaded linker phase at the end, which
is unavoidable, but on the whole it scales pretty well.

M.

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