Note: Results may vary, depending on distance from your Git servers. In my
completely unscientific benchmarks using
time, after the following steps,
git pull went from ~5s, using GitHub, to ~0.1s, using EC2 on AWS Singapore.
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5 seconds just to tell you that your Git repository is already up-to-date? Unacceptable.
Enable SSH Connection Sharing and Persistence
In Singapore, the round-trip time to github.com is ~250ms. Establishing an SSH
connection every time you perform a Git operation costs many round-trips, but
you can keep them around and reuse them with the following lines in
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ControlMaster auto enables the sharing of multiple SSH sessions over a single
network connection, and auto-creating a master connection if it does not already
ControlPath /tmp/%r@%h:%p specifies the path to the control socket used for
%r will be substituted by the remote login username,
by the target host name and
%p by the port.
ControlPersist yes keeps the master connection open in the background
git pull goes down to ~1s, a 5x improvement. Of course, this speeds
up your other repeated SSH connections too!
Setup Git Mirror with Automatic Mirroring to GitHub
For sub-second Git remote operations, you’re going to need a server with low
latency. (Imagine, when physically working together, you could
git pull the
very moment someone says “Pushed!”.)
However, you can still have all the niceties GitHub provides, by automatically pushing to GitHub from your server. There are several alternatives for keeping GitHub updated, like using cron jobs or multiple remotes, but I think using a post-receive hook is the most elegant solution.
On your server, set up a GitHub deploy key:
Go to your target repository’s Settings –> Deploy Keys –> Add deploy key and paste the public key in and submit. Then you can mirror your repository:
To automatically to mirror to GitHub after you’ve pushed, set up a
Git hook at
Your Git client won’t disconnect till the script has completed, so a simple
git push --mirror would defeat the purpose of setting this up, since you’d be
adding on GitHub’s latency to your pushes again. So, we background the process
and keep it running after logging out using
nohup, and redirect all I/O streams to
/dev/null to prevent SSH from hanging on logout.
Make the hook executable:
Now you can use your new Git mirror locally. Assuming you have added the server’s private key to ssh-agent:
You could clone it:
Or change your existing repository’s remote:
Taken alone, using the Git mirror brings
git pull down to ~1.2s. When combined
with SSH connection sharing:
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0.1s Git remote operations. Awesome.