gh-action: allow manual bench run with filter

The bench workflow can now be run manually with an optional
criterion filter and optional git ref. This way, specific
benchmarks can be run for specific commits and compard.
The github CLI tool is a convenient way to start manual runs.

Author: robinhundt

.github/workflows/bench.yml

@@ -4,6 +4,16 @@ on:
   push:
     branches:
       - "main"
+  workflow_dispatch:
+    inputs:
+      filter:
+        description: 'Optional filter for cargo bench (e.g., a specific benchmark name)'
+        default: ''
+        required: false
+      ref:
+        description: 'Optional git ref to benchmark'
+        default: ''
+        required: false
 
 jobs:
   benchmarks:
@@ -13,6 +23,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           submodules: recursive
+          ref: ${{ github.event.inputs.ref }}
       - name: Install nightly
         uses: dtolnay/rust-toolchain@master
         id: toolchain
@@ -32,9 +43,9 @@ jobs:
           bencher run \
           --project cryprot \
           --token '${{ secrets.BENCHER_API_TOKEN }}' \
-          --branch main \
+          --branch '${{github.ref_name}}' \
           --testbed ubicloud-standard-4 \
           --threshold-measure latency \
           --threshold-test t_test \
           --threshold-upper-boundary 0.99 \
-          'cargo bench'
+          'cargo bench ${{ github.event.inputs.filter }}'