Re: [PATCH v1 0/3] [RFC] Speeding up checkout (and merge, rebase, etc)

From: Ben Peart <peartben@gmail.com>
Date: Jul 27, 2018, 15:50 UTC
Message-ID: <ab7338a4-4a63-c722-35b1-a5b0784d66bf@gmail.com>
In-Reply-To: <xmqqd0v9pyzu.fsf@gitster-ct.c.googlers.com>

On 7/26/2018 3:40 PM, Junio C Hamano wrote:

Show 10 quoted lines

> 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.
>

I had a few minutes so applied this patch to the latest git for windows and ran the p0006-read-tree-checkout.sh perf test on the git repo as well as a synthetic large repo. The results look quite promising - up to a 28.8% savings!

I'm out of time this week but am _very_ interested in seeing if this can be completed successfully.

Ben

git repo results ================

Test this tree gfw --------------------------------------------------------------------------------------------------------- 0006.2: read-tree br_base br_ballast (1000001) 1.37(0.04+0.09) 1.34(0.03+0.09) -2.2% 0006.3: switch between br_base br_ballast (1000001) 50.21(0.07+0.09) 50.22(0.03+0.09) +0.0% 0006.4: switch between br_ballast br_ballast_plus_1 (1000001) 3.58(0.03+0.09) 4.61(0.03+0.10) +28.8% 0006.5: switch between aliases (1000001) 3.67(0.03+0.07) 4.56(0.01+0.07) +24.3%

large synthetic repo results ============================

Test this tree gfw --------------------------------------------------------------------------------------------------------- 0006.2: read-tree br_base br_ballast (1000001) 1.33(0.04+0.04) 1.33(0.04+0.06) +0.0% 0006.3: switch between br_base br_ballast (1000001) 48.96(0.03+0.12) 50.76(0.03+0.07) +3.7% 0006.4: switch between br_ballast br_ballast_plus_1 (1000001) 3.64(0.01+0.09) 4.59(0.06+0.07) +26.1% 0006.5: switch between aliases (1000001) 3.68(0.03+0.07) 4.66(0.04+0.06) +26.6%