diff --git a/.github/workflows/ci-bench.yml b/.github/workflows/ci-bench.yml
index a6cb2207..008c82da 100644
--- a/.github/workflows/ci-bench.yml
+++ b/.github/workflows/ci-bench.yml
@@ -42,7 +42,10 @@ jobs:
         go install golang.org/x/perf/cmd/benchstat@latest
         make bench-diff
         OUTPUT=$(make print-bench-diff)
-        echo "output: $OUTPUT"
+        # because set-output doesn't support multiline content out-of-the-box
+        OUTPUT="${OUTPUT//'%'/'%25'}"
+        OUTPUT="${OUTPUT//$'\n'/'%0A'}"
+        OUTPUT="${OUTPUT//$'\r'/'%0D'}"
         echo "::set-output name=summary::$OUTPUT"
 
     - name: Comment Benchmark Diffs
diff --git a/make/bench.mk b/make/bench.mk
index 9d144b93..f34670f6 100644
--- a/make/bench.mk
+++ b/make/bench.mk
@@ -35,11 +35,11 @@ bench-diff: clean generate-optimized check-git-status
 	@echo "generated $(REPORTS_DIR)/v0.7.0.bench"
 	@git checkout $(GITHUB_SHA)
 	@echo "HEAD is now at $(shell git log -1 --format='%h') (expecting $(GITHUB_SHA))"
-	@echo "Comparing with 'master' branch"
-	@$(GOPATH)/bin/benchstat $(REPORTS_DIR)/$(GITHUB_SHA)-$(GIT_COMMIT_ID_SHORT).bench $(REPORTS_DIR)/master.bench
-	@echo ""
-	@echo "Comparing with 'v0.7.0' tag"
-	@$(GOPATH)/bin/benchstat $(REPORTS_DIR)/$(GITHUB_SHA)-$(GIT_COMMIT_ID_SHORT).bench $(REPORTS_DIR)/v0.7.0.bench | tee $(REPORTS_DIR)/diffs.txt
+	@echo "Comparing with 'master' branch" > $(REPORTS_DIR)/diffs.txt
+	@$(GOPATH)/bin/benchstat $(REPORTS_DIR)/$(GITHUB_SHA)-$(GIT_COMMIT_ID_SHORT).bench $(REPORTS_DIR)/master.bench >> $(REPORTS_DIR)/diffs.txt
+	@echo "" >> $(REPORTS_DIR)/diffs.txt
+	@echo "Comparing with 'v0.7.0' tag" >> $(REPORTS_DIR)/diffs.txt
+	@$(GOPATH)/bin/benchstat $(REPORTS_DIR)/$(GITHUB_SHA)-$(GIT_COMMIT_ID_SHORT).bench $(REPORTS_DIR)/v0.7.0.bench >> $(REPORTS_DIR)/diffs.txt
 
 .PHONY: print-bench-diff
 print-bench-diff: