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Re: fork performance

On Thu, Oct 18, 2012 at 12:52:47PM +1300, Lloyd Parkes wrote:
> So, with a slightly closer look, a guess and some tests to verify
> my guess, and I think I have found my performance problem converting
> the NetBSD CVS repositories to Mercurial.
> The CVS server forks once for each command it receives, and it receives
> a lot of commands. NetBSD fork(2) seems to be much slower than OS X
> fork(2).

I've seen things that show that a processes memory page list isn't
getting its entries merged - so there are a lot of items to process
during fork().  (cat something in /proc ...)

The malloc netbsd uses (that uses mmap() instead of sbrk()) probably
makes this much more significant.
Especially if a big C++ program - like a python interpreter - is doing
the forks().


David Laight:

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