branchmap: introduce branchheads() method

localrepo: refactor repo.branchtip() to use repo.branchmap().branchtip()

branchmap: introduce branchtip() method

branchmap: cache open/closed branch head information This lets us determine the open/closed state of a branch without reading from the changelog (which can be costly over NFS and/or with many branches).

bookmarks: allow push -B to create a new remote head (issue2372) Push is currently allowed to create a new head if there is a remote bookmark that will be updated to point to the new head. If the bookmark is not known remotely then push aborts, even if a -B argument is about to push the bookmark. This change allows push to continue in this case. This does not require a wireproto force.

template: modify showextras to return a hybrid This modifies slightly the behavior introduced in 519120a96c63 to allow showextras to return a hybrid, rather than showlist. The example in the template help file now executes and returns meaningful results.

branches: avoid unnecessary changectx.branch() calls This requires reading from the changelog, which can be costly over NFS. Note that this does not totally remove reading from the changelog; we still do that when calling changectx.closesbranch(). That call will be removed in a later patch. Running hg branches on the PyPy repo (with 996) over a busy NFS server, before this change: $ time hg --profile branches > /dev/null CallCount Recursive Total(s) Inline(s) module:lineno(function) 2042 0 2.2827 2.2827 <open> 2036 0 0.9840 0.9840 <method 'close' of 'file' objects> 2036 0 0.0464 0.0464 <method 'read' of 'file' objects> 5233 0 0.1985 0.0453 mercurial.repoview:161(changelog) 10462 0 0.0791 0.0314 mercurial.changelog:133(tip) 5233 0 0.0388 0.0176 mercurial.localrepo:26(__get__) 10462 0 0.0250 0.0126 <len> 5233 0 0.0059 0.0039 mercurial.repoview:112(filterrevs) 10462 0 0.0029 0.0029 <hash> 2034 0 0.0444 0.0444 <method 'seek' of 'file' objects> 5340 0 0.0390 0.0390 mercurial.revlog:296(rev) 2582 0 0.0371 0.0371 <zlib.decompress> 3155 0 0.1963 0.0366 mercurial.context:202(__init__) 3155 0 0.1238 0.0306 mercurial.repoview:161(changelog) 3155 0 0.0261 0.0080 mercurial.changelog:183(rev) 9465 0 0.0061 0.0061 <isinstance> 1096 0 0.0023 0.0023 <binascii.unhexlify> 4251 0 0.0014 0.0014 <len> 2059 0 3.7341 0.0332 mercurial.changelog:270(read) 2059 0 3.6304 0.0307 mercurial.revlog:907(revision) 2057 0 0.0262 0.0137 mercurial.changelog:28(decodeextra) 4118 0 0.0094 0.0094 <method 'split' of 'str' objects> 4118 0 0.0270 0.0048 mercurial.encoding:61(tolocal) 2059 0 0.0040 0.0040 <method 'index' of 'str' objects> 10462 0 0.0791 0.0314 mercurial.changelog:133(tip) 10462 0 0.0289 0.0207 mercurial.changelog:190(node) 10462 0 0.0188 0.0091 <len> 52433 20932 0.0478 0.0310 <len> 20932 0 0.0221 0.0168 mercurial.revlog:262(__len__) 2059 0 3.6304 0.0307 mercurial.revlog:907(revision) real 0m4.361s user 0m0.986s sys 0m0.237s After this change: $ time hg --profile branches > /dev/null CallCount Recursive Total(s) Inline(s) module:lineno(function) 1069 0 1.1098 1.1098 <open> 1063 0 0.4865 0.4865 <method 'close' of 'file' objects> 4122 0 0.1811 0.0404 mercurial.repoview:161(changelog) 8240 0 0.0712 0.0272 mercurial.changelog:133(tip) 4122 0 0.0378 0.0177 mercurial.localrepo:26(__get__) 8240 0 0.0221 0.0115 <len> 4122 0 0.0057 0.0033 mercurial.repoview:112(filterrevs) 8240 0 0.0025 0.0025 <hash> 3029 0 0.1979 0.0371 mercurial.context:202(__init__) 3029 0 0.1278 0.0310 mercurial.repoview:161(changelog) 3029 0 0.0230 0.0081 mercurial.changelog:183(rev) 9087 0 0.0061 0.0061 <isinstance> 1096 0 0.0026 0.0026 <binascii.unhexlify> 4125 0 0.0014 0.0014 <len> 4229 0 0.0337 0.0337 mercurial.revlog:296(rev) 1061 0 0.0296 0.0296 <method 'seek' of 'file' objects> 1063 0 0.0292 0.0292 <method 'read' of 'file' objects> 8240 0 0.0712 0.0272 mercurial.changelog:133(tip) 8240 0 0.0271 0.0196 mercurial.changelog:190(node) 8240 0 0.0169 0.0083 <len> 40476 16488 0.0422 0.0271 <len> 16488 0 0.0193 0.0152 mercurial.revlog:262(__len__) 1342 0 0.0241 0.0241 <zlib.decompress> 9445 0 0.0336 0.0224 mercurial.changelog:190(node) 9445 0 0.0112 0.0112 mercurial.revlog:317(node) 1074 0 1.9102 0.0224 mercurial.changelog:270(read) 1074 0 1.8397 0.0202 mercurial.revlog:907(revision) 1073 0 0.0187 0.0099 mercurial.changelog:28(decodeextra) 2148 0 0.0061 0.0061 <method 'split' of 'str' objects> 2148 0 0.0184 0.0034 mercurial.encoding:61(tolocal) real 0m2.402s user 0m0.735s sys 0m0.177s

branchmap: add documentation on the branchcache on-disk format

revlog: allow tuning of the chunk cache size (via format.chunkcachesize) Running perfmoonwalk on the Mercurial repo (with almost 20,000 changesets) on Mac OS X with an SSD, before this change: $ hg --config format.chunkcachesize=1024 perfmoonwalk ! wall 2.022021 comb 2.030000 user 1.970000 sys 0.060000 (best of 5) (16,154 cache hits, 3,840 misses.) $ hg --config format.chunkcachesize=4096 perfmoonwalk ! wall 1.901006 comb 1.900000 user 1.880000 sys 0.020000 (best of 6) (19,003 hits, 991 misses.) $ hg --config format.chunkcachesize=16384 perfmoonwalk ! wall 1.802775 comb 1.800000 user 1.800000 sys 0.000000 (best of 6) (19,746 hits, 248 misses.) $ hg --config format.chunkcachesize=32768 perfmoonwalk ! wall 1.818545 comb 1.810000 user 1.810000 sys 0.000000 (best of 6) (19,870 hits, 124 misses.) $ hg --config format.chunkcachesize=65536 perfmoonwalk ! wall 1.801350 comb 1.810000 user 1.800000 sys 0.010000 (best of 6) (19,932 hits, 62 misses.) $ hg --config format.chunkcachesize=131072 perfmoonwalk ! wall 1.805879 comb 1.820000 user 1.810000 sys 0.010000 (best of 6) (19,963 hits, 31 misses.) We may want to change the default size in the future based on testing and user feedback.

revlog: read/cache chunks in fixed windows of 64 KB When reading a revlog chunk, instead of reading up to 64 KB ahead of the request offset and caching that, this change caches a fixed window before and after the requested data that falls on 64 KB boundaries. This increases cache hits when reading revlogs backwards. Running perfmoonwalk on the Mercurial repo (with almost 20,000 changesets) on Mac OS X with an SSD, before this change: $ hg perfmoonwalk ! wall 2.307994 comb 2.310000 user 2.120000 sys 0.190000 (best of 5) (Each run has 10,668 cache hits and 9,304 misses.) After this change: $ hg perfmoonwalk ! wall 1.814117 comb 1.810000 user 1.810000 sys 0.000000 (best of 6) (19,931 cache hits, 62 misses.) On a busy NFS share, before this change: $ hg perfmoonwalk ! wall 17.000034 comb 4.100000 user 3.270000 sys 0.830000 (best of 3) After: $ hg perfmoonwalk ! wall 1.746115 comb 1.670000 user 1.660000 sys 0.010000 (best of 5)