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)
#!/usr/bin/env python
#
# posplit - split messages in paragraphs on .po/.pot files
#
# license: MIT/X11/Expat
#
import sys
import polib
def addentry(po, entry, cache):
e = cache.get(entry.msgid)
if e:
e.occurrences.extend(entry.occurrences)
else:
po.append(entry)
cache[entry.msgid] = entry
def mkentry(orig, delta, msgid, msgstr):
entry = polib.POEntry()
entry.merge(orig)
entry.msgid = msgid or orig.msgid
entry.msgstr = msgstr or orig.msgstr
entry.occurrences = [(p, int(l) + delta) for (p, l) in orig.occurrences]
return entry
if __name__ == "__main__":
po = polib.pofile(sys.argv[1])
cache = {}
entries = po[:]
po[:] = []
for entry in entries:
msgids = entry.msgid.split(u'\n\n')
if entry.msgstr:
msgstrs = entry.msgstr.split(u'\n\n')
else:
msgstrs = [u''] * len(msgids)
if len(msgids) != len(msgstrs):
# places the whole existing translation as a fuzzy
# translation for each paragraph, to give the
# translator a chance to recover part of the old
# translation - erasing extra paragraphs is
# probably better than retranslating all from start
if 'fuzzy' not in entry.flags:
entry.flags.append('fuzzy')
msgstrs = [entry.msgstr] * len(msgids)
delta = 0
for msgid, msgstr in zip(msgids, msgstrs):
if msgid:
newentry = mkentry(entry, delta, msgid, msgstr)
addentry(po, newentry, cache)
delta += 2 + msgid.count('\n')
po.save()