Re: [RFC/PATCH v2 1/1] cygwin: Add fast_lstat() and fast_fstat() functions

On 2013-07-15 21.49, Junio C Hamano wrote:

Mark Levedahl [off-list ref] writes:

quoted

quoted

In order to limit the adverse effects caused by this implementation,
we provide a new "fast stat" interface, which allows us to use this
only for interactions with the index (i.e. the cached stat data).

Signed-off-by: Ramsay Jones <redacted>
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I've tested this on Cygwin 1.7 on WIndows 7 , comparing to the results
using your prior patch (removing the Cygwin specific lstat entirely)
and get the same results with both, so this seems ok from me.

My comparison point was created by reverting your current patch from
pu, then reapplying your earlier patch on top, so the only difference
was which approach was used to address the stat functions.

Caveats:
1) I don't find any speed improvement of the current patch over the
previous one (the tests actually ran faster with the earlier patch,
though the difference was less than 1%).

Hm, measuring the time for the test suite is one thing,
did you measure the time of "git status" with and without the patch?

(I don't have my test system at hand, so I can test in a few days/weeks)

quoted

2) I still question this whole approach, especially having this
non-POSIX compliant mode be the default. Running in this mode breaks
interoperability with Linux, but providing a Linux environment is the
*primary* goal of Cygwin.

Sounds like we are better off without this patch, and instead remove
the "schizophrenic stat"?  I do not have a strong opinion either
way, except that I tend to agree with your point 2) above.

My understanding is that we want both:
Introduction of fast_lstat() as phase 1,
and the removal of the "schizophrenic stat" in compat/cygwin.c
as phase 2. (or do I missunderstand something ?)


And yes, phase 3:
The day we have a both reliable and fast 
lstat() in cygwin, we can remove compat/cygwin.[ch]