diff --git a/.circleci/config.yml b/.circleci/config.yml
index 35c2ca3..7dbf99b 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -46,7 +46,7 @@ jobs:
                  -DLLVM_ENABLE_ASSERTIONS=ON \
                  -DLLVM_ENABLE_RTTI=ON
               # TODO(tjingrant): why is RTTI necessary?
-              cmake --build . --target check-mlir
+              cmake --build . --target check-mlir -- -j 4
             fi
       - save_cache:
           key: LLVM-PROJECT-{{ arch }}