[PATCH 3 of 6] changegroup: remove one special case from lookupmflinknode

[Martin von Zweigbergk]

On Fri, Dec 4, 2015 at 11:25 AM Augie Fackler <raf at durin42.com> wrote:

> # HG changeset patch
> # User Augie Fackler <augie at google.com>
> # Date 1449244546 18000
> #      Fri Dec 04 10:55:46 2015 -0500
> # Node ID 1477b679417ada21523eeb4ae945e907e8df5f8c
> # Parent  ef0693b1540667fd183fe1364dbf308f919a0fd6
> # EXP-Topic cg3
> changegroup: remove one special case from lookupmflinknode
>
> In the fastpathlinkrev case, lookupmflinknode was a very complicated
> way of saying mfs.__getitem__, so let's just get that case out of our
> way so it's easier to understand what's going on.
>
> Timings for bundle --all on my hg repo, tested with hgperf:
> Before:
> ! wall 23.442445 comb 23.440000 user 23.250000 sys 0.190000 (best of 3)
>
> After:
> ! wall 20.272187 comb 20.270000 user 20.190000 sys 0.080000 (best of 3)
>

As we talked about on IM, the speedup seems to come from 1/6, not from this
patch. I'll move these paragraphs to that patch in flight.


>
> diff --git a/mercurial/changegroup.py b/mercurial/changegroup.py
> --- a/mercurial/changegroup.py
> +++ b/mercurial/changegroup.py
> @@ -7,6 +7,7 @@
>
>  from __future__ import absolute_import
>
> +import operator
>  import os
>  import struct
>  import tempfile
> @@ -656,21 +657,23 @@ class cg1packer(object):
>          # Callback for the manifest, used to collect linkrevs for filelog
>          # revisions.
>          # Returns the linkrev node (collected in lookupcl).
> -        def lookupmflinknode(x):
> -            """Callback for looking up the linknode for manifests.
> +        if fastpathlinkrev:
> +            lookupmflinknode = mfs.__getitem__
> +        else:
> +            def lookupmflinknode(x):
> +                """Callback for looking up the linknode for manifests.
>
> -            Returns the linkrev node for the specified manifest.
> +                Returns the linkrev node for the specified manifest.
>
> -            SIDE EFFECT:
> +                SIDE EFFECT:
>
> -              fclnodes gets populated with the list of relevant
> -              file nodes if we're not using fastpathlinkrev.
> +                  fclnodes gets populated with the list of relevant
> +                  file nodes.
>
> -            Note that this means you can't trust fclnodes until
> -            after manifests have been sent to the client.
> -            """
> -            clnode = mfs[x]
> -            if not fastpathlinkrev:
> +                Note that this means you can't trust fclnodes until
> +                after manifests have been sent to the client.
> +                """
> +                clnode = mfs[x]
>                  mdata = ml.readfast(x)
>                  for f in mfchangedfiles[x]:
>                      try:
> @@ -683,7 +686,7 @@ class cg1packer(object):
>                      fclnode = fclnodes.setdefault(n, clnode)
>                      if clrevorder[clnode] < clrevorder[fclnode]:
>                          fclnodes[n] = clnode
> -            return clnode
> +                return clnode
>
>          mfnodes = self.prune(ml, mfs, commonrevs)
>          for x in self._packmanifests(mfnodes, lookupmflinknode):
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