diff --git a/.circleci/config.yml b/.circleci/config.yml
index e07912f01..f941abf01 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -196,6 +196,7 @@ commands:
           environment:
             PRE_COMMIT_HOME: &pre_commit_cache_dir /cache/precommit
           name: "Run pre-commit checks"
+          no_output_timeout: 30m
           command: python -m pre_commit run --all-files
       - save_cache:
           key: *pre_commit_cache_key
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 1dfd39167..287febed7 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -19,6 +19,7 @@ repos:
         args: [--style=file, -i]
       - id: clang-tidy
         args: [--fix, --fix-errors]
+        require_serial: true  # Set parallelism to one otherwise it gwt out of memory on CircleCI.
   - repo: https://github.com/psf/black
     rev: 19.10b0
     hooks: