Re: vc-print-log vs. bzr log

[Stephen Berman]

On Sat, 15 Sep 2012 15:37:13 +0200 Andreas Schwab <address@hidden> wrote:

> Stephen Berman <address@hidden> writes:
>
>> When I'm visiting a file on a local branch of the Emacs bzr trunk and
>> type `M-! bzr log -r-1 RET' I see the log entry in less than one second.
>
> Try again passing the file name.  Does it make a difference?

Somewhat; see below.

On Sat, 15 Sep 2012 16:51:33 +0300 Eli Zaretskii <address@hidden> wrote:

>> From: Stephen Berman <address@hidden>
>> Date: Sat, 15 Sep 2012 15:07:03 +0200
>> 
>> When I'm visiting a file on a local branch of the Emacs bzr trunk and
>> type `M-! bzr log -r-1 RET' I see the log entry in less than one second.
>> When I type `C-x v l RET RET' ±19 seconds elapse before the log is
>> displayed (and the lag time is the same if I limit the display to one
>> entry).  Is this time difference expected?
>
> Yes, to some degree, because these two commands do 2 different things.
> The first one shows the last commit in the branch.  The second one
> shows the commits only to the file you are visiting, which means
> digging deeper into the version history.

I understand that, but ±19 seconds vs <1 second?  Is that the best VC
can do?

> However, even if the file you are visiting is the one modified by the
> last revision, bzr is slower when a file argument is passed.  

I see this too, but it's still very much quicker than VC.  Here are some
timing tests, with emacs -Q:

>From /data/steve/bzr/emacs/quickfixes/ typing `M-! time bzr log -r-1':

real    0m0.428s
user    0m0.305s
sys     0m0.053s

>From outside of this branch typing `M-! time bzr log -r-1
/data/steve/bzr/emacs/quickfixes/':

real    0m0.484s
user    0m0.323s
sys     0m0.044s

>From outside of this branch typing `M-! time bzr log -r-1
/data/steve/bzr/emacs/quickfixes/lisp/':

real    0m1.330s
user    0m0.957s
sys     0m0.106s

>From outside of this branch typing `M-! time bzr log -r-1
/data/steve/bzr/emacs/quickfixes/lisp/gnus/:

real    0m0.760s
user    0m0.480s
sys     0m0.083s

>From outside of this branch typing `M-! time bzr log -r-1
/data/steve/bzr/emacs/quickfixes/lisp/gnus/gnus-group.el' (where this
file is the one modified by the last revision on this branch):

real    0m0.612s
user    0m0.404s
sys     0m0.066s

>From outside of this branch typing `M-! time bzr log -r-1
/data/steve/bzr/emacs/quickfixes/lisp/gnus/gnus-agent.el' (where this
file is not the one modified by the last revision on this branch):

real    0m0.557s
user    0m0.384s
sys     0m0.067s

>                                                               I guess
> this is something to report as a bug to bzr bug tracker.
>
> Btw, did you really mean "C-x v l RET RET", or did you mean something
> like "C-u C-x v l RET 1 RET"?

Yes, sorry, I mistakenly omitted the prefix argument (from my posting,
not from the command I typed in Emacs).

Steve Berman