From: Ben Peart <peartben@gmail.com>
Date: Fri, 27 Jul 2018 16:22:18 GMT
Subject: Re: [PATCH v1 0/3] [RFC] Speeding up checkout (and merge, rebase, etc)
Message-ID: <434074a8-1045-8c8f-da0c-873436acf40e@gmail.com>
In-Reply-To: <20180727154241.GA21288@duynguyen.home>



On 7/27/2018 11:42 AM, Duy Nguyen wrote:
> On Thu, Jul 26, 2018 at 12:40:05PM -0700, Junio C Hamano wrote:
>> Duy Nguyen <pclouds@gmail.com> writes:
>>
>>> I'm excited so I decided to try out anyway. This is what I've come up
>>> with. Switching trees on git.git shows it could skip plenty entries,
>>> so promising. It's ugly and it fails at t6020 though, there's still
>>> work ahead. But I think it'll stop here.
>>
>> We are extremely shallow compared to projects like the kernel and
>> stuff from java land, so that is quite an interesting find.
>>
> 
> Yeah. I've got a more or less complete patch now with full test suite
> passed and even with linux.git, the numbers look pretty good.
> 
> Ben, is it possible for you to try this one out? I don't suppose it
> will be that good on a real big repo. But I'm curious how much faster
> could this patch does.
> 

Thanks Duy.  I'm super excited about this so did a quick and dirty 
manual perf test.

I ran "git checkout" 5 times, discarded the first 2 runs and averaged 
the last 3 with and without this patch on top of VFSForGit in a large repo.

Without this patch average times were 16.97
With this patch average times were 10.55

That is a significant improvement!

I really have to run but I'll be back next week to dig in more.

Ben