CI runner checks are too infrequent

Summary

I am running gitlab-runner for projects on gitlab.com and it takes way too long between checks for new jobs

Steps to reproduce

Excellent question.

• Create a project on gitlab.com.
• Run a runner for it on your own system (mine is installed on macOS via brew).
• Make a trivial pipeline
• Observe it takes several minutes from when you push changes to when the runner starts building them

What is the current bug behavior?

Several minutes between runner checks

What is the expected correct behavior?

A few seconds between runner checks

Relevant logs and/or screenshots

# ps -ajxwww | grep gitlab-runner
    1  1402  1402  1402 ?           -1 Ssl      0   0:06 /usr/lib/gitlab-runner/gitlab-runner run --working-directory /home/gitlab-runner --config /etc/gitlab-runner/config.toml --service gitlab-runner --syslog --user gitlab-runner

# grep interval /etc/gitlab-runner/config.toml
check_interval = 10

# grep "Checking for jobs" /var/log/syslog
Aug 29 03:09:27 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:09:27 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:14:55 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:14:55 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:19:34 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:19:34 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:24:40 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:24:40 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:30:32 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:30:32 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:36:49 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received
Aug 29 03:36:49 gitlab-ci-dispatch gitlab-runner[1402]: Checking for jobs... received

Note the 5+ minute intervals between checks even though check_interval is set to 10s (and I have multiple workers configured, so it should be even shorter than that).

Output of checks

This bug happens on GitLab.com