From 3bc1cdc049b2944ba16d9226c881d8d52ed98dfe Mon Sep 17 00:00:00 2001
From: not-matthias <matthias@codspeed.io>
Date: Sat, 16 May 2026 14:25:54 -0700
Subject: [PATCH 1/2] ci: shard bpf-tests by integration test binary

Each memtrack integration test binary runs its cases serially because
the eBPF tracker can't overlap with itself in one process. Sharding at
the test-binary level lets the four binaries build and run in parallel
across jobs, dropping the critical path from ~13min to ~5min.
---
 .github/workflows/ci.yml | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 88a1383b..b8979347 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -87,6 +87,13 @@ jobs:
 
   bpf-tests:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        # Each memtrack integration test binary runs its cases serially
+        # (eBPF tracker can't overlap with itself in one process), so we
+        # shard at the test-binary level to parallelize across jobs.
+        test: [c_tests, cpp_tests, rust_tests, spawn_tests]
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
@@ -102,7 +109,7 @@ jobs:
       - name: Run tests
         env:
           RUST_LOG: debug
-        run: sudo -E $(which cargo) test -- --test-threads 1 --nocapture
+        run: sudo -E $(which cargo) test --lib --test ${{ matrix.test }} -- --test-threads 1 --nocapture
         working-directory: crates/memtrack
 
       # Since we ran the tests with sudo, the build artifacts will have root ownership

From 4eac647797a5b836ef780d498e494c34f001ede2 Mon Sep 17 00:00:00 2001
From: not-matthias <matthias@codspeed.io>
Date: Wed, 20 May 2026 10:32:57 +0200
Subject: [PATCH 2/2] ci: give each bpf-tests shard its own cache key

Previously all four matrix shards shared one rust-cache key and raced
to save, leaving three failed reservations per run and only one entry
that quickly aged out. Per-shard keys eliminate the race.
---
 .github/actions/install-rust/action.yml | 6 ++++++
 .github/workflows/ci.yml                | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/.github/actions/install-rust/action.yml b/.github/actions/install-rust/action.yml
index 04bee8af..e4c7a777 100644
--- a/.github/actions/install-rust/action.yml
+++ b/.github/actions/install-rust/action.yml
@@ -5,6 +5,10 @@ inputs:
     description: Comma-separated list of additional rustup components to install (e.g. "rustfmt, clippy").
     required: false
     default: ""
+  cache-key:
+    description: Extra value appended to the rust-cache key, used to give matrix shards distinct caches and avoid concurrent save races.
+    required: false
+    default: ""
 runs:
   using: composite
   steps:
@@ -16,3 +20,5 @@ runs:
       shell: bash
       run: echo "${{ inputs.components }}" | tr ',' '\n' | xargs rustup component add
     - uses: Swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4 # v2
+      with:
+        key: ${{ inputs.cache-key }}
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b8979347..4b794bb7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -100,6 +100,8 @@ jobs:
           lfs: true
           submodules: true
       - uses: ./.github/actions/install-rust
+        with:
+          cache-key: ${{ matrix.test }}
       - name: Install dependencies required for libbpf-sys (vendored feature)
         run: sudo apt-get update && sudo apt-get install -y autopoint bison flex