diff --git a/.github/workflows/mmtk.yml b/.github/workflows/mmtk.yml
index f8c62612d4133b..901915d6042ad7 100644
--- a/.github/workflows/mmtk.yml
+++ b/.github/workflows/mmtk.yml
@@ -25,7 +25,7 @@ jobs:
     strategy:
       matrix:
         include:
-          - test_task: btest
+          - test_task: test-all
             os: ubuntu-20.04
       fail-fast: false
 
@@ -92,17 +92,16 @@ jobs:
 
       - run: $SETARCH make
 
-      - name: make ${{ matrix.test_task }} --mmtk
+      - name: make ${{ matrix.test_task }} RUN_OPTS="$RUN_OPTS"
         run: >-
           $SETARCH make -s ${{ matrix.test_task }}
-          ${TESTS:+TESTS="$TESTS"}
           ${{ !contains(matrix.test_task, 'bundle') && 'RUBYOPT=-w' || '' }}
         timeout-minutes: 40
         env:
-          TESTS: $(cat $srcdir/mmtk_tests.txt | ruby -e 'puts ARGF.map(&:strip).reject { |line| line.start_with?("#") }.join(" ")')
           RUBY_TESTOPTS: '-q --tty=no'
           TEST_BUNDLED_GEMS_ALLOW_FAILURES: ''
           PRECHECK_BUNDLED_GEMS: 'no'
+          RUN_OPTS: '--mmtk --mmtk-plan=StickyImmix'
 
       - name: Clean build directory
         run: rm -rf $builddir/mmtk-ruby