--- a/hgext3rd/evolve/stablesort.py	Sun Sep 08 11:56:11 2019 +0200
+++ b/hgext3rd/evolve/stablesort.py	Sun Sep 08 13:31:28 2019 +0200
@@ -156,6 +156,46 @@
         displayer.flush(ctx)
     displayer.close()
 
+@eh.command(
+    b'debugstablesortcache',
+    [] + commands.formatteropts,
+    _(b''))
+def debugstablesortcache(ui, repo, **opts):
+    """display data about the stable sort cache of a repository
+    """
+    unfi = repo.unfiltered()
+    revs = unfi.revs('all()')
+    nbrevs = len(revs)
+    ui.write('number of revisions: %12d\n' % nbrevs)
+    merge = unfi.revs('merge()')
+    nbmerge = len(merge)
+    cache = unfi.stablesort
+    ui.write('number of merge:     %12d\n' % nbmerge)
+    alljumps = []
+    alljumpssize = []
+    for r in merge:
+        jumps = cache.getjumps(unfi, r)
+        if jumps is None:
+            continue # not a merge
+        jumps = list(jumps)
+        alljumps.append(jumps)
+        alljumpssize.append(len(jumps))
+    nbjumps = sum(alljumpssize)
+    ui.write('number of jumps:     %12d\n' % nbjumps)
+    if not nbjumps:
+        return 0
+    avgjumps = nbjumps / float(len(alljumpssize))
+    ui.write('average jumps:                 %6.3f\n' % avgjumps)
+    alljumpssize.sort()
+    medianjumps = alljumpssize[len(alljumpssize) // 2]
+    ui.write('median jumps:        %12d\n' % medianjumps)
+    tensjumps = alljumpssize[len(alljumpssize) * 9 // 10]
+    ui.write('90%% jumps:           %12d\n' % tensjumps)
+    centsjumps = alljumpssize[len(alljumpssize) * 99 // 100]
+    ui.write('99%% jumps:           %12d\n' % centsjumps)
+    ui.write('max jumps:           %12d\n' % max(alljumpssize))
+    ui.write('jump cache size:     %12d bytes\n' % (nbjumps * 12))
+
 def stablesort_branchpoint(repo, revs, mergecallback=None):
     """return '::revs' topologically sorted in "stable" order