[MERGE][#230567] Faster (local) branch

[Robert Collins]

On Thu, 2008-05-29 at 11:20 +1000, Andrew Bennetts wrote:
> Aaron Bentley wrote:
> > Ian Clatworthy wrote:
> [...]
> > > 
> > > Fair enough. Right now, we're chmod'ing each file where executable
> > > is not None. I changed this to only set the mode is it was True.
> > 
> > AFAIK, that's not accurate.  Without further data, you don't know
> > whether the execute bit is being set on newly-created files.
> 
> Wow, really?  What platform/filesystem/environment creates new files with the
> execute bit set but also lets you unset it afterwards?  Is this a Windows issue?
> 
> > > Even with hundreds of executable bits set in the mozilla repo, the
> > > time drops from 5% of a big number (24 secs) to < 1% of a smaller
> > > number (15 secs). I can update the TODO if you like.
> > 
> > Hmm.  I can't seem to find that old branch.  But the basic strategy was
> > to use os.open instead of the builtin open.  os.open allows the
> > permissions to be specified at file creation time, so that we only have
> > to do one syscall, and can skip the chmod.
> 
> That sounds sane to me if we really do need this degree of control over file
> creation.

It was an experimental branch Aaron and I created in London a couple of
years back; at that time we didn't see a performance gain - but a
smaller delta now will show up more - we have moved the goalposts a long
way.

however - os.open() still honours umask, which as I recall is why we
discarded the branch.

-Rob
-- 
GPG key available at: <http://www.robertcollins.net/keys.txt>.
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