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In article <87ocxl3903.fsf%himring.draga.com@localhost>,
Jim Wise <jwise%draga.com@localhost> wrote:
>Quick question, out of curiosity, about NetBSD's vfork():
>In 1998, we switched vfork() back from the 4.4 semantics (Copy-on-Write
>until exec) to the traditional BSD semantics (shared address space
>between parent and child until exec()). I'm curious about the how this
> -- was this an optimization, with code working pretty much as before,
> but gaining speed from not doing a bunch of unneeded Copy-on-Write
Yes. Look in the mailing lists on how much the shell performance improved
when elric switched it to vfork for the common cases.
> -- are there programs in-tree which depend on the shared address space
> -- are there common third-party apps which do?
Probably not (except tcsh).
> -- what do other systems do?
Print 0 in hashstat in csh.
>Needless to say, there's no lurking change behind this question -- just
Another important semantic is that vfork() has is that the parent is suspended
until the child execs.
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