Re: [PATCH 2/2] pack-objects: report actual number of threads to be used

[Dan McGee <dpmcgee@gmail.com>]

On Sat, Apr 4, 2009 at 1:06 PM, Jeff King <peff@peff.net> wrote:
> On Sat, Apr 04, 2009 at 11:59:56AM -0500, Dan McGee wrote:
>
>> In the case of a small repository, pack-objects is smart enough to not start
>> more threads than necessary. However, the output to the user always reports
>> the value of the pack.threads configuration and not the real number of
>> threads to be used. This is easily fixed by moving the printing of the
>> message after we have partitioned our work.
>>
>> (pack.threads is on autodetect and would be set to 4)
>> $ git-repack -a -d -f
>> Counting objects: 55, done.
>> Delta compression using 2 threads.
>> Compressing objects: 100% (48/48), done.
>> Writing objects: 100% (55/55), done.
>> Total 55 (delta 10), reused 0 (delta 0)
>
> That makes sense to me, though I wonder if it may confuse and frustrate
> users who are expecting their awesome quad-core machine to be using 4
> threads when it only uses 2. Is it worth printing both values, or some
> indicator that we could have been using more?

I thought of this, but decided it wasn't really worth it. The default
window size of 10 makes it a very rare case that you will use fewer
than 4 threads. With the default, each thread needs a minimum of 20
objects, so even a 100-object repository would spawn the 4 threads.

I wouldn't be opposed to printing something special when
active_threads != delta_search_threads if other people do think it to
be necessary though.

-Dan