Re: Parallel checkout (Was Re: 0 bot for Git)

[Duy Nguyen <pclouds@gmail.com>]

On Fri, Apr 15, 2016 at 6:18 PM, Christian Couder
<christian.couder@gmail.com> wrote:
> On Fri, Apr 15, 2016 at 11:51 AM, Duy Nguyen <pclouds@gmail.com> wrote:
>> On Fri, Apr 15, 2016 at 12:04:49AM +0200, Christian Couder wrote:
>>>
>>> There is a draft of an article about the first part of the Contributor
>>> Summit in the draft of the next Git Rev News edition:
>>>
>>> https://github.com/git/git.github.io/blob/master/rev_news/drafts/edition-14.md
>>
>> Thanks. I read the sentence "This made people mention potential
>> problems with parallelizing git checkout" and wondered what these
>> problems were.
>
> It may have been Michael or Peff (CC'ed) saying that it could break
> some builds as the timestamps on the files might not always be ordered
> in the same way.

Very subtle. I suppose if we dumb down the distribution algorithm, we
could make it stable (even though it won't be the same as serial
checkout). Performance will degrade, not sure if it's still worth
parallelizing at that point

> Now perhaps parallel checkout could be activated only if a config
> option was set. (Yeah, I know it looks like I am very often asking for
> config options.)

And I think it could be unconditionally activated at clone time (I
can't imagine different timestamp order can affect anything at that
point), where the number of files to checkout is biggest.
-- 
Duy