If you are wondering, v1 of this patch was appended to an email
that is part of the "cygwin: Remove the Win32 l/stat() functions"
thread.
Changes from v1:
- add comment in git-compat-util.h to explain the use
of the "fast" stat variants.
- remove the fast_stat() function, along with the now
redundant code in compat/cygwin.c
- add the fast_fstat() function; this is used by code
in write_entry() (entry.c:139), even though it is not
actually called by cygwin.
- replaced an additional call to lstat with fast_lstat.
- a commit message
This patch, which was built on master @ commit 56df44a, has passed
the full test suite:
$ GIT_SKIP_TESTS='t0008 t0061.3 t0070.3 t4130 t9010 t9300' \
make test >test-outp15 2>&1
$
After Torsten's patch, I didn't need to skip t0070.3; that was just
force of habit! Once Mark's PIPE prerequisite patch is applied, I
would not have to skip t0008, t9010 and t9300.
I also used one of Torsten's tests, on git.git, to provide a quick
check on performance:
$ time bin-wrappers/git -c core.filemode=true status -uno
which gave the following results (5 runs, discard fastest, slowest
and average remaining three):
master @ 56df44a + this patch
true 0.641, 0.656, (0.688), 0.657, (0.640) = 0.651
false 0.500, (0.531), 0.500, (0.469), 0.500 = 0.500
master @ 56df44a
true 0.670, (0.734), (0.638), 0.648, 0.663 = 0.660
false (0.509), (0.490), 0.496, 0.497, 0.498 = 0.497
So, this patch does not cause any performance regression (+/- 1%).
However, I was a bit worried by the timings, until I noticed that
(on cygwin) the timings are affected by running from the build
directory. Note the timings for v1.8.3:
v1.8.3 (build)
true 0.671, 0.672, (0.640), 0.672, (0.969) = 0.672
false (0.515), 0.532, 0.516, 0.516, (0.547) = 0.521
v1.8.3 (installed)
true (0.250), (0.266), 0.265, 0.250, 0.265 = 0.260
false (0.109), (0.125), 0.109, 0.125, 0.125 = 0.120
Also, just for comparison, here are the numbers for Linux and
MinGW on the same laptop:
Linux MinGW
master + patch 0.045 0.115
master @ 56df44a ----- 0.110
v1.8.3 (build) 0.045 0.109
v1.8.3 (installed) 0.045 0.094
So, this patch seems to cause a 5% slowdown on MinGW; I haven't
looked into this yet. Note that the "build directory slowdown" is
much less pronounced on MinGW, and non existent (or too small to
notice) on Linux.
This patch is marked RFC because:
- I don't like the function names; suggestions welcome!
- Is fast_fstat() necessary; should we remove the use of
fstat() in write_entry() instead. (I don't think so).
- Is the 5% slowdown on MinGW a real problem? (are the
static inline functions being in-lined?)
- I need to double check that I have replaced all relevant
lstat() calls.
ATB,
Ramsay Jones
Ramsay Jones (1):
cygwin: Add fast_lstat() and fast_fstat() functions
builtin/apply.c | 8 ++++----
builtin/commit.c | 2 +-
builtin/ls-files.c | 2 +-
builtin/rm.c | 2 +-
builtin/update-index.c | 2 +-
check-racy.c | 2 +-
compat/cygwin.c | 48 ++++++++++--------------------------------------
compat/cygwin.h | 17 +++++++++--------
diff-lib.c | 2 +-
diff.c | 2 +-
entry.c | 6 +++---
git-compat-util.h | 27 +++++++++++++++++++++++++--
help.c | 5 +----
path.c | 9 +--------
preload-index.c | 2 +-
read-cache.c | 6 +++---
unpack-trees.c | 8 ++++----
17 files changed, 68 insertions(+), 82 deletions(-)
--
1.8.3
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