[PATCH v1] diffcore-rename: speed up register_rename_src
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- git@jeffhostetler.com <git@jeffhostetler.com>
- Date
- Apr 18, 2017, 19:44 UTC
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- <20170418194421.22453-2-git@jeffhostetler.com>
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- <20170418194421.22453-1-git@jeffhostetler.com>
From: Jeff Hostetler <jeffhost@microsoft.com>
Teach register_rename_src() to see if new file pair can simply be appended to the rename_src[] array before performing the binary search to find the proper insertion point.
This is a performance optimization. This routine is called during run_diff_files in status and the caller is iterating over the sorted index, so we should expect to be able to append in the normal case. The existing insert logic is preserved so we don't have to assume that, but simply take advantage of it if possible.
Using t/perf/p0005-status.h (from a parallel patch series), we get the following improvement on a 4.2M file repo:
Test HEAD~1 HEAD 0005.2: read-tree status br_ballast (4194305) 59.14(31.85+18.79) 55.48(28.52+20.71) -6.2%
On a 1M file repo: Test HEAD~1 HEAD 0005.2: read-tree status br_ballast (1000001) 8.20(4.82+3.35) 7.91(4.57+3.27) -3.5%
On a smaller repo, like linux.git (58K files), results are masked by normal I/O variance.
Test HEAD~1 HEAD 0005.2: read-tree status br_ballast (57994) 0.43(0.30+0.13) 0.42(0.31+0.12) -2.3% 0005.2: read-tree status br_ballast (57994) 0.42(0.32+0.09) 0.43(0.34+0.10) +2.4% 0005.2: read-tree status br_ballast (57994) 0.44(0.33+0.10) 0.42(0.26+0.16) -4.5%
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> --- diffcore-rename.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/diffcore-rename.c b/diffcore-rename.c index f7444c8..543a409 100644 --- a/diffcore-rename.c +++ b/diffcore-rename.c @@ -81,6 +81,18 @@ static struct diff_rename_src *register_rename_src(struct diff_filepair *p) first = 0; last = rename_src_nr; + + if (last > 0) { + struct diff_rename_src *src = &(rename_src[last-1]); + int cmp = strcmp(one->path, src->p->one->path); + if (!cmp) + return src; + if (cmp > 0) { + first = last; + goto append_it; + } + } + while (last > first) { int next = (last + first) >> 1; struct diff_rename_src *src = &(rename_src[next]); @@ -94,6 +106,7 @@ static struct diff_rename_src *register_rename_src(struct diff_filepair *p) first = next+1; } +append_it: /* insert to make it at "first" */ ALLOC_GROW(rename_src, rename_src_nr + 1, rename_src_alloc); rename_src_nr++;
-- 2.9.3