diff --git a/mercurial/registrar.py b/mercurial/registrar.py
--- a/mercurial/registrar.py
+++ b/mercurial/registrar.py
@@ -166,6 +166,16 @@
     Optional argument 'takeorder' indicates whether a predicate function
     takes ordering policy as the last argument.
 
+    Optional argument 'weight' indicates the estimated run-time cost, useful
+    for static optimization, default is 1. Higher weight means more expensive.
+    Usually, revsets that are fast and returns only one single revision has a
+    weight of 0.5 (ex. a string symbol); revsets with O(changelog) complexity
+    have weight 10 (ex.  author); revsets which also needs reading manifest
+    diffs usually have weight 30 (ex. adds); revset reading file contents
+    usually have weight 100 (ex. contains). Note: those values are not
+    absolute, if the revset has a same big-O time complexity as `contains`,
+    but with a smaller constant, it might have a weight of 90.
+
     'revsetpredicate' instance in example above can be used to
     decorate multiple functions.
 
@@ -178,9 +188,10 @@
     _getname = _funcregistrarbase._parsefuncdecl
     _docformat = "``%s``\n    %s"
 
-    def _extrasetup(self, name, func, safe=False, takeorder=False):
+    def _extrasetup(self, name, func, safe=False, takeorder=False, weight=1):
         func._safe = safe
         func._takeorder = takeorder
+        func._weight = weight
 
 class filesetpredicate(_funcregistrarbase):
     """Decorator to register fileset predicate
diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -253,7 +253,7 @@
 #   repo - current repository instance
 #   subset - of revisions to be examined
 #   x - argument in tree form
-symbols = {}
+symbols = revsetlang.symbols
 
 # symbols which can't be used for a DoS attack for any given input
 # (e.g. those which accept regexes as plain strings shouldn't be included)
@@ -276,7 +276,7 @@
         sourceset = getset(repo, fullreposet(repo), x)
     return subset & baseset([destutil.destmerge(repo, sourceset=sourceset)])
 
-@predicate('adds(pattern)', safe=True)
+@predicate('adds(pattern)', safe=True, weight=30)
 def adds(repo, subset, x):
     """Changesets that add a file matching pattern.
 
@@ -288,7 +288,7 @@
     pat = getstring(x, _("adds requires a pattern"))
     return checkstatus(repo, subset, pat, 1)
 
-@predicate('ancestor(*changeset)', safe=True)
+@predicate('ancestor(*changeset)', safe=True, weight=0.5)
 def ancestor(repo, subset, x):
     """A greatest common ancestor of the changesets.
 
@@ -394,7 +394,7 @@
         ps.add(r)
     return subset & ps
 
-@predicate('author(string)', safe=True)
+@predicate('author(string)', safe=True, weight=10)
 def author(repo, subset, x):
     """Alias for ``user(string)``.
     """
@@ -462,7 +462,7 @@
     bms -= {node.nullrev}
     return subset & bms
 
-@predicate('branch(string or set)', safe=True)
+@predicate('branch(string or set)', safe=True, weight=10)
 def branch(repo, subset, x):
     """
     All changesets belonging to the given branch or the branches of the given
@@ -595,7 +595,7 @@
     cs = _children(repo, subset, s)
     return subset & cs
 
-@predicate('closed()', safe=True)
+@predicate('closed()', safe=True, weight=10)
 def closed(repo, subset, x):
     """Changeset is closed.
     """
@@ -604,7 +604,7 @@
     return subset.filter(lambda r: repo[r].closesbranch(),
                          condrepr='<branch closed>')
 
-@predicate('contains(pattern)')
+@predicate('contains(pattern)', weight=100)
 def contains(repo, subset, x):
     """The revision's manifest contains a file matching pattern (but might not
     modify it). See :hg:`help patterns` for information about file patterns.
@@ -654,7 +654,7 @@
     return subset.filter(lambda r: _matchvalue(r),
                          condrepr=('<converted %r>', rev))
 
-@predicate('date(interval)', safe=True)
+@predicate('date(interval)', safe=True, weight=10)
 def date(repo, subset, x):
     """Changesets within the interval, see :hg:`help dates`.
     """
@@ -664,7 +664,7 @@
     return subset.filter(lambda x: dm(repo[x].date()[0]),
                          condrepr=('<date %r>', ds))
 
-@predicate('desc(string)', safe=True)
+@predicate('desc(string)', safe=True, weight=10)
 def desc(repo, subset, x):
     """Search commit message for string. The match is case-insensitive.
 
@@ -722,7 +722,7 @@
     # Like ``descendants(set)`` but follows only the first parents.
     return _descendants(repo, subset, x, followfirst=True)
 
-@predicate('destination([set])', safe=True)
+@predicate('destination([set])', safe=True, weight=10)
 def destination(repo, subset, x):
     """Changesets that were created by a graft, transplant or rebase operation,
     with the given revisions specified as the source.  Omitting the optional set
@@ -891,7 +891,7 @@
 
     return subset & s
 
-@predicate('first(set, [n])', safe=True, takeorder=True)
+@predicate('first(set, [n])', safe=True, takeorder=True, weight=0)
 def first(repo, subset, x, order):
     """An alias for limit().
     """
@@ -1012,7 +1012,7 @@
     getargs(x, 0, 0, _("all takes no arguments"))
     return subset & spanset(repo)  # drop "null" if any
 
-@predicate('grep(regex)')
+@predicate('grep(regex)', weight=10)
 def grep(repo, subset, x):
     """Like ``keyword(string)`` but accepts a regex. Use ``grep(r'...')``
     to ensure special escape characters are handled correctly. Unlike
@@ -1097,7 +1097,7 @@
                                    'exclude=%r, default=%r, rev=%r>',
                                    pats, inc, exc, default, rev))
 
-@predicate('file(pattern)', safe=True)
+@predicate('file(pattern)', safe=True, weight=10)
 def hasfile(repo, subset, x):
     """Changesets affecting files matched by pattern.
 
@@ -1139,7 +1139,7 @@
     hiddenrevs = repoview.filterrevs(repo, 'visible')
     return subset & hiddenrevs
 
-@predicate('keyword(string)', safe=True)
+@predicate('keyword(string)', safe=True, weight=10)
 def keyword(repo, subset, x):
     """Search commit message, user name, and names of changed files for
     string. The match is case-insensitive.
@@ -1157,7 +1157,7 @@
 
     return subset.filter(matches, condrepr=('<keyword %r>', kw))
 
-@predicate('limit(set[, n[, offset]])', safe=True, takeorder=True)
+@predicate('limit(set[, n[, offset]])', safe=True, takeorder=True, weight=0)
 def limit(repo, subset, x, order):
     """First n members of set, defaulting to 1, starting from offset.
     """
@@ -1259,7 +1259,7 @@
         pass
     return baseset(datarepr=('<min %r, %r>', subset, os))
 
-@predicate('modifies(pattern)', safe=True)
+@predicate('modifies(pattern)', safe=True, weight=30)
 def modifies(repo, subset, x):
     """Changesets modifying files matched by pattern.
 
@@ -1403,7 +1403,7 @@
     # some optimizations from the fact this is a baseset.
     return subset & o
 
-@predicate('outgoing([path])', safe=False)
+@predicate('outgoing([path])', safe=False, weight=10)
 def outgoing(repo, subset, x):
     """Changesets not found in the specified destination repository, or the
     default push location.
@@ -1654,7 +1654,7 @@
             return baseset([r])
     return baseset()
 
-@predicate('removes(pattern)', safe=True)
+@predicate('removes(pattern)', safe=True, weight=30)
 def removes(repo, subset, x):
     """Changesets which remove files matching pattern.
 
@@ -1794,7 +1794,7 @@
 
     return subset.filter(matches, condrepr=('<matching%r %r>', fields, revs))
 
-@predicate('reverse(set)', safe=True, takeorder=True)
+@predicate('reverse(set)', safe=True, takeorder=True, weight=0)
 def reverse(repo, subset, x, order):
     """Reverse order of set.
     """
@@ -1862,7 +1862,8 @@
 
     return args['set'], keyflags, opts
 
-@predicate('sort(set[, [-]key... [, ...]])', safe=True, takeorder=True)
+@predicate('sort(set[, [-]key... [, ...]])', safe=True, takeorder=True,
+           weight=10)
 def sort(repo, subset, x, order):
     """Sort set by keys. The default sort order is ascending, specify a key
     as ``-key`` to sort in descending order.
@@ -2033,7 +2034,7 @@
     return subset & orphan
 
 
-@predicate('user(string)', safe=True)
+@predicate('user(string)', safe=True, weight=10)
 def user(repo, subset, x):
     """User name contains string. The match is case-insensitive.
 
@@ -2042,7 +2043,7 @@
     """
     return author(repo, subset, x)
 
-@predicate('wdir()', safe=True)
+@predicate('wdir()', safe=True, weight=0)
 def wdir(repo, subset, x):
     """Working directory. (EXPERIMENTAL)"""
     # i18n: "wdir" is a keyword
@@ -2097,7 +2098,7 @@
     return baseset([r for r in ls if r in s])
 
 # for internal use
-@predicate('_intlist', safe=True, takeorder=True)
+@predicate('_intlist', safe=True, takeorder=True, weight=0)
 def _intlist(repo, subset, x, order):
     if order == followorder:
         # slow path to take the subset order
diff --git a/mercurial/revsetlang.py b/mercurial/revsetlang.py
--- a/mercurial/revsetlang.py
+++ b/mercurial/revsetlang.py
@@ -49,6 +49,8 @@
 
 keywords = {'and', 'or', 'not'}
 
+symbols = {}
+
 _quoteletters = {'"', "'"}
 _simpleopletters = set(pycompat.iterbytestr("()[]#:=,-|&+!~^%"))
 
@@ -441,21 +443,7 @@
     elif op == 'func':
         f = getsymbol(x[1])
         wa, ta = _optimize(x[2])
-        if f in ('author', 'branch', 'closed', 'date', 'desc', 'file', 'grep',
-                 'keyword', 'outgoing', 'user', 'destination'):
-            w = 10 # slow
-        elif f in ('modifies', 'adds', 'removes'):
-            w = 30 # slower
-        elif f == "contains":
-            w = 100 # very slow
-        elif f == "ancestor":
-            w = 0.5
-        elif f in ('reverse', 'limit', 'first', 'wdir', '_intlist'):
-            w = 0
-        elif f == "sort":
-            w = 10 # assume most sorts look at changelog
-        else:
-            w = 1
+        w = getattr(symbols.get(f), '_weight', 1)
         return w + wa, (op, x[1], ta)
     raise ValueError('invalid operator %r' % op)