On 12/08/2011 08:29 AM, Charles Wilson wrote: > On 12/8/2011 5:21 AM, Gary V. Vaughan wrote: >> The recently pushed series of patches included the controversial >> introduction of an additional 3 forks per invocation, which might >> add a minute or two of wall-clock time to giant builds on windows. >> By assuming that windows will run shell scripts on some shell with >> all the modern optional features that libtool wants, this patch >> eliminates even those 3 new forks. >> >> Okay to push? > > Has anybody done a comparison between: > > cygwin + libtool + dash/posh (e.g. small, fast shell -- without XSI)
Umm, dash has XSI features (where XSI features covers things like
${var##prefix}). It is only shells like Solaris /bin/sh that lack this
mandatory POSIX feature. Meanwhile, libtool is using more than just XSI
extensions; for example, it is probing for bash's += variable append
extension. I'm not sure how much difference += makes (especially since
it is not shaving on forks, but is reducing O(n^2) malloc behavior for
large piece-wise constructions), but do know that XSI variable usage
definitely shaves a lot of forkes.
As for actual timing comparisons, I have not done any recently.
--
Eric Blake ebl...@redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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