Mercurial > hg
view setup_bdiff_cffi.py @ 30289:1f92056c4066
revlog: optimize _chunkraw when startrev==endrev
In many cases, _chunkraw() is called with startrev==endrev. When
this is true, we can avoid an extra index lookup and some other
minor operations.
On the mozilla-unified repo, `hg perfrevlogchunks -c` says this
has the following impact:
! read w/ reused fd
! wall 0.371846 comb 0.370000 user 0.350000 sys 0.020000 (best of 27)
! wall 0.337930 comb 0.330000 user 0.300000 sys 0.030000 (best of 30)
! read batch w/ reused fd
! wall 0.014952 comb 0.020000 user 0.000000 sys 0.020000 (best of 197)
! wall 0.014866 comb 0.010000 user 0.000000 sys 0.010000 (best of 196)
So, we've gone from ~25x slower than batch to ~22.5x slower.
At this point, there's probably not much else we can do except
implement an optimized function in the index itself, including in C.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 23 Oct 2016 10:40:33 -0700 |
parents | a8933d992a71 |
children |
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from __future__ import absolute_import import cffi import os ffi = cffi.FFI() ffi.set_source("_bdiff_cffi", open(os.path.join(os.path.join(os.path.dirname(__file__), 'mercurial'), 'bdiff.c')).read(), include_dirs=['mercurial']) ffi.cdef(""" struct bdiff_line { int hash, n, e; ssize_t len; const char *l; }; struct bdiff_hunk; struct bdiff_hunk { int a1, a2, b1, b2; struct bdiff_hunk *next; }; int bdiff_splitlines(const char *a, ssize_t len, struct bdiff_line **lr); int bdiff_diff(struct bdiff_line *a, int an, struct bdiff_line *b, int bn, struct bdiff_hunk *base); void bdiff_freehunks(struct bdiff_hunk *l); void free(void*); """) if __name__ == '__main__': ffi.compile()