Cygwin performance results linux-headers-2.6.21-2: bzr 0.18 vs hg 0.9.4

[Robert Collins]

On Thu, 2007-08-02 at 20:36 +0300, Jari Aalto wrote:
> I ran tests under Cygwin as well for comparison. P II/400
> W2ksp4/latest Cygwin. Both programs are native Cygwin applications
> with Cygwin Python 2.5. 
> 
> The difference is huge. Let me know if I can help profiling.

Wow the difference certainly is significant. If you could get lsprof
output for some of this it would be useful. Also IIRC terminal output is
extremely slow for cygwin, so I'd like to know --quiet/--no-verbose
figures for these.

More below

> Jari
> 
> bzr 0.18
> 
>     $ bzr init
>     real    0m52.398s
>     user    0m2.814s
>     sys     0m8.802s

This is amazingly slow. My guess here is that it is the time to load bzr
from disk. hg has many fewer python modules, and I really should finish
my import simulator off given this info. For comparison:

$ time bzr init bar
real    0m0.464s
user    0m0.332s
sys     0m0.100s

Also, what plugins do you have installed?

>     $ bzr add .
>     real    2m56.609s
>     user    0m16.854s
>     sys     0m16.403s

Again a huge difference between user+sys and real. That suggests
blocking IO (e.g. terminal or waiting for disk) occuring.

>     $ bzr ci -m "- commit"
>     real    10m56.302s
>     user    2m4.989s
>     sys     1m1.748s

And again, about the same ratio.

I think it would be fantastic if you can spend some time profiling and
determining where the time is going. We're serious about making bzr fast
- and on linux we are comparable to hg for many operations today, so
this suggests something that cygwin is bad at, and that we make heavy
use of, interacting.

-Rob

-- 
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