How to speed up checkout for big repos?

I would like to limit number of cloned branches to minimum. As example, cloning of the master branch takes ~7s at ~3MiB/s rate:

$ time git clone --single-branch --branch master https://github.com/plokhotnyuk/jsoniter-scala.git
Cloning into 'jsoniter-scala'...
remote: Enumerating objects: 260, done.
remote: Counting objects: 100% (260/260), done.
remote: Compressing objects: 100% (221/221), done.
remote: Total 29660 (delta 39), reused 236 (delta 27), pack-reused 29400
Receiving objects: 100% (29660/29660), 13.22 MiB | 2.92 MiB/s, done.
Resolving deltas: 100% (10355/10355), done.
 
real	0m6,484s
user	0m2,249s
sys	0m0,368s

While the checkout action with the following configuration takes more than 1.5m:

      - uses: actions/checkout@v1
        with:
          ref: ${{ github.ref }}
          fetch-depth: 100

Which options can be used to speed it up?

[ericsciple]

@plokhotnyuk i’m making perf improvements with https://github.com/actions/checkout/pull/70

i’ll merge it into master tomorrow and push a tag v2-beta

[plokhotnyuk]

@ericsciple Thank you a lot for you support!

The following config works fine and completes both steps in ~4 seconds:

      - uses: actions/checkout@v2
        with:
          fetch-depth: 100
      - name: Fetch tags
        run: git fetch --depth=100 origin +refs/tags/*:refs/tags/*

It didn’t work with depth=1 for me.

Using of tags to get version of the latest release is quite handful, especially in case of multiple maintained branches.