Re: on when to checksum

[Linus Torvalds <torvalds@osdl.org>]

On Wed, 20 Apr 2005, Tom Lord wrote:
> 
> How many times per day do you invoke `write-tree' and why?

Every single commit does a write-tree, so when I merge with Andrew, it's 
usually a series of 100-250 of them in a row.

(Actually, _usualyl_ it's smaller series, but it's the big series that can
be painful enough to matter).

> It takes a large multiple of `0.3s' to get me to take you seriously
> on this point.

The thing is, I don't "trickle" things in. That would be horribly 
inefficient for me. So I go over the patches, make a mbox, and do them all 
in one go. And then they need to happen _fast_. If it takes 20 minutes, I 
go away for coffee or something, and then if something didn't apply 
half-way through, I will have lost my "context".

That's why I want things instant. Not because I have huge daily throughput 
issues, but I have huge _latency_ issues. 

I considered doing a "two-level" thing, where I first did the stuff in a
light-weigth patch manager, and then batched things up in the background
for the real thing. But the fact is, I don't think it's needed. Not the
way git performs now. If I can apply a hundred patches in a minute or two,
I have not "lost the context" if it turns out that there is some silly
glitch with one of them.

		Linus