Re: Emacs Bazaar repository

[Jonathan Lange]

On Thu, Mar 13, 2008 at 7:04 PM, dhruva <address@hidden> wrote:
> Hi,
>   I got bzr setup and running on my M$-XP box. I got the bzr repo of
>  emacs (by downloading the emacs.tar.gz) and updated it to the latest.
>   I wanted to make sure the recent changesets are pulled in. I typed
>  "bzr log -l 10". It took ~24 seconds (elapsed time from perfmon)
>  consistently. Whereas Mercurial (hg log -l 10) on the trunk to 2
>  seconds (and the mercurial repo is on a CIFS mounted drive while bzr
>  repo was on local disk). GIT was fastest though even on a CIFS mounted
>  system.
>

I was a bit curious about this so I asked my friendly neighbourhood
Bazaar hacker (CCd). He tells me that comparing 'bzr log' to 'hg log'
is like comparing apples with ... umm, apple trees. Bazaar's log
displays all merges and thus has to do calculations on the whole
ancestry graph. Mercurial's log just displays the mainline history.
'bzr log --line' is a better comparison.

Unfortunately, 'bzr log --line' is nowhere near as fast as it could
be. We did a quick test and saw that 'log --line -l 10' takes about
half the time as 'log -l 10' which is still too slow. It's still doing
too much work with the whole graph.

We whipped up a quick hack and got it doing the same thing in about
0.25 seconds, which is getting close.

>  IMHO, the performance aspects must be considered seriously.
>

Definitely. I hate waiting for anything, computers most of all. I'll
hassle Martin and try to get this fixed. Alternatively, the Bazaar
project welcomes patches with open arms. :)

jml