obsolete: use parsers.fm1readmarker if it exists for a ~38% perf win
This moves perfloadmarkers on my linux workstation (63494 markers from
mpm, crew, and myself) performance from
! wall 0.357657 comb 0.360000 user 0.350000 sys 0.010000 (best of 28)
to
! wall 0.222345 comb 0.220000 user 0.210000 sys 0.010000 (best of 41)
which is a pretty good improvement.
On my BSD machine, which is ancient and slow, before:
! wall 3.584964 comb 3.578125 user 3.539062 sys 0.039062 (best of 3)
after:
! wall 2.267974 comb 2.265625 user 2.195312 sys 0.070312 (best of 5)
I feel like we could do better by moving the whole generator function
into C, but I didn't want to tackle that right away.
--- a/mercurial/obsolete.py Fri Jan 23 15:11:25 2015 -0500
+++ b/mercurial/obsolete.py Tue Jan 20 13:38:07 2015 -0500
@@ -68,7 +68,7 @@
"""
import struct
-import util, base85, node
+import util, base85, node, parsers
import phases
from i18n import _
@@ -301,6 +301,15 @@
# Loop on markers
stop = len(data) - _fm1fsize
ufixed = util.unpacker(_fm1fixed)
+
+ fast = getattr(parsers, 'fm1readmarker', None)
+ if fast is not None:
+ while off <= stop:
+ ret = fast(data, off)
+ yield ret[1:]
+ off += ret[0]
+ return
+
while off <= stop:
# read fixed part
o1 = off + fsize