Silly Question About Timing

Silly Question About Timing

[Hilco Wijbenga]

Hi all,

This is a bit silly but I'm trying to time how long it takes to enter
a Git controlled directory. I guess this is more of a GNU/Linux
question then anything else.

I've noticed that entering a Git controlled project directory takes
quite some time so I wanted to measure exactly how much (it's the
prompt I'm using that's taking the time, I suspect). I first tried (a
bit naive, I admit :-) )

time cd my-project

This doesn't work of course. Obviously, writing a script doesn't work
either because then the prompt isn't calculated. Next I tried

date +%H:%M:%S.%N ; cd my-project-abc ; date +%H:%M:%S.%N

but, surprisingly (to me), that doesn't work either. It simply prints
the two timestamps and *then* does the cd (or, at least, that's how it
seems to behave).

So how would one do this? :-)

Cheers,
Hilco

P.S. This slow cd is only the first time, afterwards things have been cached.

Re: Silly Question About Timing

[Seth Robertson]

In message <CAE1pOi1+FQNoPZ_P-fmFx-YhnUYzMQT=6zh3s-OyT71vcDm=wQ@mail.gmail.com>, Hilco Wijbenga writes:

    I've noticed that entering a Git controlled project directory takes
    quite some time so I wanted to measure exactly how much (it's the
    prompt I'm using that's taking the time, I suspect). I first tried (a
    bit naive, I admit :-) )

    time cd my-project

Your confusion is because you are measuring the wrong thing.  I'm
assuming, here, that you have a shell prompt which is giving you all
sorts of status about the git repository.  The "cd" operation is
instantaneous, it is the shell attempting to compute the new prompt
which is slow.

Exactly how your shell does this is shell dependent, but you might
want to look at your setting of $PROMPT_COMMAND.  Then you can test it
by running something like:

time sh -c "cd git-directory; $PROMPT_COMMAND"

					-Seth Robertson

Re: Silly Question About Timing

[Hilco Wijbenga]

On 9 February 2012 13:16, Seth Robertson <in-gitvger@baka.org> wrote:
>
> In message <CAE1pOi1+FQNoPZ_P-fmFx-YhnUYzMQT=6zh3s-OyT71vcDm=wQ@mail.gmail.com>, Hilco Wijbenga writes:
>
>    I've noticed that entering a Git controlled project directory takes
>    quite some time so I wanted to measure exactly how much (it's the
>    prompt I'm using that's taking the time, I suspect). I first tried (a
>    bit naive, I admit :-) )
>
>    time cd my-project
>
> Your confusion is because you are measuring the wrong thing.  I'm
> assuming, here, that you have a shell prompt which is giving you all
> sorts of status about the git repository.  The "cd" operation is
> instantaneous, it is the shell attempting to compute the new prompt
> which is slow.

Yes, exactly.

> Exactly how your shell does this is shell dependent, but you might
> want to look at your setting of $PROMPT_COMMAND.  Then you can test it
> by running something like:
>
> time sh -c "cd git-directory; $PROMPT_COMMAND"

I tried that and it's still instantaneous.

The culprit is

export PS1='\[\033[01;32m\]\u@\h\[\033[01;34m\] \w \W$(__git_ps1 "
(%s)")\$\[\033[00m\] '

but I can't get that to run. Simply running

echo $PS1

doesn't work and I have been unable to get the __git_ps1 part to do anything.

Re: Silly Question About Timing

[Frans Klaver]

On Thu, 09 Feb 2012 22:48:25 +0100, Hilco Wijbenga  
<hilco.wijbenga@gmail.com> wrote:

> ... and I have been unable to get the __git_ps1 part to do anything.

I get the following on msysgit:

/c/msysgit (devel) $ time __git_ps1
(devel)
real    0m0.406s
user    0m0.136s
sys     0m0.107s

Would be odd if that doesn't work on Linux.