diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index c2b79aa..297da2a 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -3,8 +3,13 @@ on: [push, pull_request]
 jobs:
   test:
     strategy:
+      fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest]
+        target:
+        - unit-test-2-cpu
+        - unit-test-4-cpu
+        - unit-test-4-cpu-race
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v3
@@ -12,7 +17,28 @@ jobs:
       with:
         go-version: "1.17.13"
     - run: make fmt
-    - run: make race
-    - run: make test
+    - env:
+        TARGET: ${{ matrix.target }}
+      run: |
+        case "${TARGET}" in
+          unit-test-2-cpu)
+            CPU=2 make test-simulate
+            CPU=2 make test
+            ;;
+          unit-test-4-cpu)
+            CPU=4 make test-simulate
+            CPU=4 make test
+            ;;
+          unit-test-4-cpu-race)
+            CPU=4 ENABLE_RACE=true make test-simulate
+            CPU=4 ENABLE_RACE=true make test
+            ;;
+          *)
+            echo "Failed to find target"
+            exit 1
+            ;;
+        esac
+      shell: bash
+    - run: make coverage
     - name: golangci-lint
       uses: golangci/golangci-lint-action@0ad9a0988b3973e851ab0a07adf248ec2e100376 # v3.3.1
diff --git a/.gitignore b/.gitignore
index 18312f0..cca8d2b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,5 +3,6 @@
 *.swp
 /bin/
 cover.out
+cover-*.out
 /.idea
 *.iml
diff --git a/Makefile b/Makefile
index 67e3390..c5256eb 100644
--- a/Makefile
+++ b/Makefile
@@ -2,10 +2,17 @@ BRANCH=`git rev-parse --abbrev-ref HEAD`
 COMMIT=`git rev-parse --short HEAD`
 GOLDFLAGS="-X main.branch $(BRANCH) -X main.commit $(COMMIT)"
 
-race:
-	@TEST_FREELIST_TYPE=hashmap go test -v -race -test.run="TestSimulate_(100op|1000op)"
-	@echo "array freelist test"
-	@TEST_FREELIST_TYPE=array go test -v -race -test.run="TestSimulate_(100op|1000op)"
+TESTFLAGS_RACE=-race=false
+ifdef ENABLE_RACE
+	TESTFLAGS_RACE=-race=true
+endif
+
+TESTFLAGS_CPU=
+ifdef CPU
+	TESTFLAGS_CPU=-cpu=$(CPU)
+endif
+
+TESTFLAGS = $(TESTFLAGS_RACE) $(TESTFLAGS_CPU)
 
 fmt:
 	!(gofmt -l -s -d $(shell find . -name \*.go) | grep '[a-z]')
@@ -14,12 +21,28 @@ lint:
 	golangci-lint run ./...
 
 test:
-	TEST_FREELIST_TYPE=hashmap go test -timeout 30m -v -coverprofile cover.out -covermode atomic
-	TEST_FREELIST_TYPE=hashmap go test -v ./cmd/bbolt
+	@echo "hashmap freelist test"
+	TEST_FREELIST_TYPE=hashmap go test -v ${TESTFLAGS} -timeout 30m
+	TEST_FREELIST_TYPE=hashmap go test -v ${TESTFLAGS} ./cmd/bbolt
 
 	@echo "array freelist test"
+	TEST_FREELIST_TYPE=array go test -v ${TESTFLAGS} -timeout 30m
+	TEST_FREELIST_TYPE=array go test -v ${TESTFLAGS} ./cmd/bbolt
 
-	@TEST_FREELIST_TYPE=array go test -timeout 30m -v -coverprofile cover.out -covermode atomic
-	@TEST_FREELIST_TYPE=array go test -v ./cmd/bbolt
+test-simulate:
+	@echo "hashmap freelist test"
+	TEST_FREELIST_TYPE=hashmap go test -v ${TESTFLAGS} -test.run="TestSimulate_(100op|1000op)"
 
-.PHONY: race fmt test lint
+	@echo "array freelist test"
+	TEST_FREELIST_TYPE=array go test -v ${TESTFLAGS} -test.run="TestSimulate_(100op|1000op)"
+
+coverage:
+	@echo "hashmap freelist test"
+	TEST_FREELIST_TYPE=hashmap go test -v -timeout 30m \
+		-coverprofile cover-freelist-hashmap.out -covermode atomic
+
+	@echo "array freelist test"
+	TEST_FREELIST_TYPE=array go test -v -timeout 30m \
+		-coverprofile cover-freelist-array.out -covermode atomic
+
+.PHONY: fmt test test-simulate lint