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