[Cloud] [CRITICAL] gitserver: 2s+ echo command duration test fires regularly

Created by: tsenart

We need to find out the root cause. There seems to be a correlation with the number of go-routines going up, so my best guess is either:

1. Disk I/O contention (how can we graph this in Grafana)?
2. go-routine scheduling contention (but at 8k, that doesn't seem likely)