tracing: add a couple of trace points on obsolete and repoview

I was seeing weird stalls in some fast commands, and these trace
events help explain them.

Differential Revision: https://phab.mercurial-scm.org/D6550

mercurial/obsolete.py

@@ -899,11 +899,12 b' def getrevs(repo, name):'
 
     Such access may compute the set and cache it for future use"""
     repo = repo.unfiltered()
-    if not repo.obsstore:
-        return frozenset()
-    if name not in repo.obsstore.caches:
-        repo.obsstore.caches[name] = cachefuncs[name](repo)
-    return repo.obsstore.caches[name]
+    with util.timedcm('getrevs %s', name):
+        if not repo.obsstore:
+            return frozenset()
+        if name not in repo.obsstore.caches:
+            repo.obsstore.caches[name] = cachefuncs[name](repo)
+        return repo.obsstore.caches[name]
 
 
 # To be simple we need to invalidate obsolescence cache when:

mercurial/repoview.py

@@ -274,8 +274,8 b' class repoview(object):'
         unfiindex = unfichangelog.index
         unfilen = len(unfiindex)
         unfinode = unfiindex[unfilen - 1][7]
-
-        revs = filterrevs(unfi, self.filtername, self._visibilityexceptions)
+        with util.timedcm('repo filter for %s', self.filtername):
+            revs = filterrevs(unfi, self.filtername, self._visibilityexceptions)
         cl = self._clcache
         newkey = (unfilen, unfinode, hash(revs), unfichangelog._delayed)
         # if cl.index is not unfiindex, unfi.changelog would be