Re: [PATCH] Put sha1dc on a diet

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Linus,

On Wed, 1 Mar 2017, Linus Torvalds wrote:

> On Wed, Mar 1, 2017 at 2:51 PM, Johannes Schindelin
> <Johannes.Schindelin@gmx.de> wrote:
> >
> > But I think bigger than just developers on Windows OS. There are many
> > developers out there working on large repositories (yes, much larger
> > than Linux). Also using Macs and Linux. I am not at all sure that we
> > want to give them an updated Git they cannot fail to notice to be much
> > slower than before.
> 
> Johannes, have you *tried* the patches?
> 
> I really don't think you have. It is completely unnoticeable in any
> normal situation. The two cases that it's noticeable is:
> 
>  - a full fsck is noticeable slower
> 
>  - a full non-local clone is slower (but not really noticeably so
> since the network traffic dominates).
> 
> In other words, I think you're making shit up. I don't think you
> understand how little the SHA1 performance actually matters. It's
> noticeable in benchmarks. It's not noticeable in any normal operation.
> 
> .. and yes, I've actually been running the patches locally since I
> posted my first version (which apparently didn't go out to the list
> because of list size limits) and now running the version in 'pu'.

If you think that the Linux repository is a big one, then your reaction is
understandable.

I have zero interest in potty language, therefore my reply is very terse:
yes, I have been looking ad SHA-1 performance, and yes, it matters. Think
an index file of 300-400MB.

Ciao,
Johannes