perf: support measuring bdiff for all changeset related data

The --all argument changes the behavior of `perfbdiff` to pull
in fulltext revision pairs for all changes related to a changeset.
The p1 and p2 manifests will be bdiffed against current. Every file
that changed between p1 and current will have its file revisions
loaded and bdiffed.

This mode of operation effectively measured the bdiff time required
for `hg commit`.

contrib/perf.py

@@ -748,7 +748,8 b' def perffncacheencode(ui, repo, **opts):'
     fm.end()
 
 @command('perfbdiff', revlogopts + formatteropts + [
-    ('', 'count', 1, 'number of revisions to test (when using --startrev)')],
+    ('', 'count', 1, 'number of revisions to test (when using --startrev)'),
+    ('', 'alldata', False, 'test bdiffs for all associated revisions')],
     '-c|-m|FILE REV')
 def perfbdiff(ui, repo, file_, rev=None, count=None, **opts):
     """benchmark a bdiff between revisions
@@ -757,7 +758,14 b' def perfbdiff(ui, repo, file_, rev=None,'
 
     With ``--count``, benchmark bdiffs between delta parents and self for N
     revisions starting at the specified revision.
+
+    With ``--alldata``, assume the requested revision is a changeset and
+    measure bdiffs for all changes related to that changeset (manifest
+    and filelogs).
     """
+    if opts['alldata']:
+        opts['changelog'] = True
+
     if opts.get('changelog') or opts.get('manifest'):
         file_, rev = None, file_
     elif rev is None:
@@ -769,8 +777,25 b' def perfbdiff(ui, repo, file_, rev=None,'
 
     startrev = r.rev(r.lookup(rev))
     for rev in range(startrev, min(startrev + count, len(r) - 1)):
-        dp = r.deltaparent(rev)
-        textpairs.append((r.revision(dp), r.revision(rev)))
+        if opts['alldata']:
+            # Load revisions associated with changeset.
+            ctx = repo[rev]
+            mtext = repo.manifest.revision(ctx.manifestnode())
+            for pctx in ctx.parents():
+                pman = repo.manifest.revision(pctx.manifestnode())
+                textpairs.append((pman, mtext))
+
+            # Load filelog revisions by iterating manifest delta.
+            man = ctx.manifest()
+            pman = ctx.p1().manifest()
+            for filename, change in pman.diff(man).items():
+                fctx = repo.file(filename)
+                f1 = fctx.revision(change[0][0] or -1)
+                f2 = fctx.revision(change[1][0] or -1)
+                textpairs.append((f1, f2))
+        else:
+            dp = r.deltaparent(rev)
+            textpairs.append((r.revision(dp), r.revision(rev)))
 
     def d():
         for pair in textpairs: