diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index 706a40690..4e6f4567f 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -23,6 +23,8 @@ jobs:
     runs-on: ubuntu-20.04
     env:
       CI_BUILD_STAGE_NAME: build
+      CI_RUNS_ON: ${{ matrix.os }}
+      CACHE_KEY: ${{ matrix.os }}-${{ matrix.compiler.cc }}-coverage
     steps:
 
     - uses: actions/checkout@v2
@@ -32,7 +34,7 @@ jobs:
         cache-name: ccache
       with:
         path: ${{ github.workspace }}/.ccache
-        key: coverage-${{ env.cache-name }}-${{ github.sha }}
+        key: ${{ env.CACHE_KEY }}-${{ env.cache-name }}-${{ github.sha }}
         restore-keys: coverage-${{ env.cache-name }}
 
     - name: Install dependencies for build
@@ -70,6 +72,8 @@ jobs:
     runs-on: ubuntu-20.04
     env:
       CI_BUILD_STAGE_NAME: test
+      CI_RUNS_ON: ${{ matrix.os }}
+      CACHE_KEY: ${{ matrix.os }}-${{ matrix.compiler.cc }}-coverage
     steps:
 
     - uses: actions/checkout@v2
@@ -79,7 +83,7 @@ jobs:
         cache-name: ccache
       with:
         path: ${{ github.workspace }}/.ccache
-        key: coverage-${{ env.cache-name }}-${{ github.sha }}
+        key: ${{ env.CACHE_KEY }}-${{ env.cache-name }}-${{ github.sha }}
         restore-keys: coverage-${{ env.cache-name }}
 
     - uses: actions/download-artifact@v2
diff --git a/nodist/code_coverage b/nodist/code_coverage
index 4dc57d96a..782bab1a7 100755
--- a/nodist/code_coverage
+++ b/nodist/code_coverage
@@ -310,18 +310,17 @@ def source_globs(*dirs):
 def run(command):
     # run a system command, check errors
     print("\t%s" % command)
-    os.system(command)
     status = subprocess.call(command, shell=True)
     if status < 0:
         raise Exception("%Error: Command failed " + command + ", stopped")
 
 
 def ci_fold_start(action):
-    print("::group::" + action)
+    print("::group::" + action, flush=True)
 
 
 def ci_fold_end():
-    print("::endgroup::\n")
+    print("::endgroup::\n", flush=True)
 
 
 #######################################################################