diff --git a/.github/workflows/diff.yaml b/.github/workflows/diff.yaml
index df9ea6bbc..e161af297 100644
--- a/.github/workflows/diff.yaml
+++ b/.github/workflows/diff.yaml
@@ -377,6 +377,16 @@ jobs:
             --groups aggregation 1000_create unwind_create dense_expand match \
             --no-strict
 
+      - name: Get branch name (merge)
+        if: github.event_name != 'pull_request'
+        shell: bash
+        run: echo "BRANCH_NAME=$(echo ${GITHUB_REF#refs/heads/} | tr / -)" >> $GITHUB_ENV
+
+      - name: Get branch name (pull request)
+        if: github.event_name == 'pull_request'
+        shell: bash
+        run: echo "BRANCH_NAME=$(echo ${GITHUB_HEAD_REF} | tr / -)" >> $GITHUB_ENV
+
       - name: Upload macro benchmark results
         run: |
           cd tools/bench-graph-client
@@ -386,7 +396,8 @@ jobs:
           ./main.py --benchmark-name "macro_benchmark" \
                     --benchmark-results-path "../../tests/macro_benchmark/.harness_summary" \
                     --github-run-id "${{ github.run_id }}" \
-                    --github-run-number "${{ github.run_number }}"
+                    --github-run-number "${{ github.run_number }}" \
+                    --head-branch-name "${{ env.BRANCH_NAME }}"
 
       - name: Run mgbench
         run: |
@@ -402,4 +413,5 @@ jobs:
           ./main.py --benchmark-name "mgbench" \
                     --benchmark-results-path "../../tests/mgbench/benchmark_result.json" \
                     --github-run-id "${{ github.run_id }}" \
-                    --github-run-number "${{ github.run_number }}"
+                    --github-run-number "${{ github.run_number }}" \
+                    --head-branch-name "${{ env.BRANCH_NAME }}"
diff --git a/tools/bench-graph-client/main.py b/tools/bench-graph-client/main.py
index e90340ef0..edb09ecde 100755
--- a/tools/bench-graph-client/main.py
+++ b/tools/bench-graph-client/main.py
@@ -8,10 +8,11 @@ the Bench Graph server.
 import json
 import logging
 import os
-import requests
 import subprocess
-from datetime import datetime
 from argparse import ArgumentParser
+from datetime import datetime
+
+import requests
 
 SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
 
@@ -32,6 +33,7 @@ def parse_args():
     argp.add_argument("--benchmark-results-path", type=str, required=True)
     argp.add_argument("--github-run-id", type=int, required=True)
     argp.add_argument("--github-run-number", type=int, required=True)
+    argp.add_argument("--head-branch-name", type=str, required=True)
     return argp.parse_args()
 
 
@@ -39,10 +41,6 @@ def post_measurement(args):
     with open(args.benchmark_results_path, "r") as f:
         data = json.load(f)
         timestamp = datetime.now().timestamp()
-        branch = subprocess.run(
-            ["git", "rev-parse", "--abbrev-ref", "HEAD"],
-            stdout=subprocess.PIPE,
-            check=True).stdout.decode("utf-8").strip()
         req = requests.post(
             f"{BENCH_GRAPH_SERVER_ENDPOINT}/measurements",
             json={
@@ -54,7 +52,7 @@ def post_measurement(args):
                 "github_run_id": args.github_run_id,
                 "github_run_number": args.github_run_number,
                 "results": data,
-                "git_branch": branch},
+                "git_branch": args.head_branch_name},
             timeout=1)
         assert req.status_code == 200, \
             f"Uploading {args.benchmark_name} data failed."