diff --git a/.github/workflows/build_ci.yml b/.github/workflows/build_ci.yml
index 51d9ad4f6..ad97e36f3 100644
--- a/.github/workflows/build_ci.yml
+++ b/.github/workflows/build_ci.yml
@@ -78,7 +78,11 @@ jobs:
         shell: 'script -q -e -c "bash {0}"'
         run: |
           python3 -m pip install codecov
-          pytest --cov=.
+          if [ $(git rev-parse --abbrev-ref HEAD) == "master" ];
+          then  # run coverage with multiprocessing but only for the daily master build (for performance reasons)
+            sed -i 's/"thread"/"thread", "multiprocessing"/g' pyproject.toml
+          fi
+          pytest --cov
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v4
         with:
diff --git a/pyproject.toml b/pyproject.toml
index 49e2d6ea0..97f01800b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -107,6 +107,7 @@ docstring-quotes = "double"
 quote-style = "single"
 
 [tool.coverage.run]
+source = ["src"]
 omit = [
     # ignore install scripts
     "src/install.py",
@@ -116,6 +117,8 @@ omit = [
     # ignore files only run inside docker
     "src/plugins/analysis/*/docker/**",
 ]
+multiprocessing = ["thread"]
+parallel = true
 
 [tool.coverage.report]
 exclude_also = [