Re: Emacs Bazaar repository

[Stephen J. Turnbull]

Martin Pool writes:

 > I believe the main problem is that we are processing the whole graph
 > to work out which revisions merged which others.

What does this mean?  That you can avoid pulling patches that cause
conflicts if they've already been applied?  But that's not terribly
interesting in most logging or mass download applications.

While I quoted Hoare on the root of all evil elsewhere, and continue
to take that as my default position, these numbers are uncomfortable.
I don't care how cold the CPU cache is, I don't want an attempt to
access a non-existent local repo to take 10s.  Nor should a
disk-to-disk copy of a 400MB directory tree take 23.5m.  The partial
clone times are heartening, although it's hard to guess what they
mean in terms of throughput.

# Initial one-branch clone.
$ time bzr clone http://bzr.notengoamigos.org/emacs/trunk/ earl-bzr
Branched 87515 revision(s).                                                     

real    101m35.490s     user    28m16.698s      sys     2m7.827s

# Clone from a local standalone branch into a shared repo.
$ time bzr clone ../earl-bzr trunk
Branched 87515 revision(s).                                                     

real    23m27.626s      user    13m57.869s      sys     1m12.516s

# Command line typo on a local URL, bzr figures it out in 10s.
$ time bzr branch EMACS_22_BASE
bzr: ERROR: Not a branch: 
"/Users/steve/Software/Emacs/emacs-bzr/EMACS_22_BASE/".

real    0m10.183s       user    0m0.457s        sys     0m1.361s

# Command line typo on a remote URL, bzr figures it out in 3.5s.
$ time bzr clone http://bzr.notengoamigos.org/emacs/EMACS_22_BASE
bzr: ERROR: Not a branch: "http://bzr.notengoamigos.org/emacs/EMACS_22_BASE/";.

real    0m3.427s        user    0m0.499s        sys     0m1.142s

# Command line typo on a remote URL, bzr figures it out in 2s.
$ time bzr clone http://bzr.notengoamigos.org/emacs/branch/EMACS_22_BASE
bzr: ERROR: Not a branch: 
"http://bzr.notengoamigos.org/emacs/branch/EMACS_22_BASE/";.

real    0m1.777s        user    0m0.480s        sys     0m0.995s

# A partial clone into the shared repo.
$ time bzr clone http://bzr.notengoamigos.org/emacs/branches/EMACS_22_BASE
Branched 83329 revision(s).                                                     

real    4m47.853s       user    2m20.361s       sys     0m25.168s

# A second partial clone into the shared repo.
$ time bzr clone http://bzr.notengoamigos.org/emacs/branches/lexbind      
Branched 48705 revision(s).                                                     

real    11m18.166s      user    3m25.059s       sys     0m33.614s