Re: Emacs Bazaar repository

[David Ingamells]

Matthieu Moy wrote:
> Andreas Schwab <address@hidden> writes:
>
>   
> > Matthieu Moy <address@hidden> writes:
> >
> >     
> > > That said, the time for bzr log to start should clearly not be _that_
> > > long. I suspect it's done on a light checkout (therefore needing
> > > network access), which git can't do at all for example.
> > >       
> > There is definitely no network access involved, it is almost 100% CPU
> > time.
> >     
>
> Yes, right. Just reproduced here (perhaps with a faster machine than
> yours) :
>
> $ time bzr log | head -1
> ------------------------------------------------------------
> bzr log  21.17s user 0.28s system 99% cpu 21.578 total
> head -1  0.00s user 0.00s system 0% cpu 21.523 total
> $ bzr --version
> Bazaar (bzr) 1.3.0.dev.0
> [...]
> $ bzr info
> Standalone tree (format: pack-0.92)
> [...]
>
> While on the git repo for Emacs,
>
> $ time git log | head -1
> commit 04eb7b6c65c8ec7550afb9cf317f51a1470f947c
> git log  0.00s user 0.00s system 64% cpu 0.012 total
> head -1  0.00s user 0.00s system 34% cpu 0.012 total
>
> Similarly, I tested a commit touching a single file (echo foo >>
> README), it takes 17 seconds with bzr, and 0.08 seconds with git.
>
>   
A small note of "warning" regarding such timing comparisons. make sure 
you are not comparing apples and oranges.

When we were choosing a new CMS tool I did a similar comparison between 
mercurial and bazaar, which mercurial won easily until I discovered why: 
mercurial first uses time stamps to check for potential updates - which 
leads to lost updates if the file update happens within one second of 
the checkout. bazaar is more thorough when checking for changes - this 
costs time but is much safer.