ci(build): Integrate nightly size experiments for continuous evaluation

.gitea/workflows/build.yml

@@ -7,23 +7,14 @@ on:
   pull_request:
     branches: [main]
   workflow_dispatch:
-    inputs:
-      build_mode:
-        description: "Build configuration"
-        type: choice
-        required: true
-        default: standard
-        options:
-          - standard
-          - nightly-experiments
 
 permissions:
   contents: read
 
 env:
   CARGO_TERM_COLOR: always
+  # Measure before stripping; package stripped copies separately.
   CARGO_PROFILE_RELEASE_STRIP: none
-  BUILD_MODE: ${{ inputs.build_mode || 'standard' }}
 
 jobs:
   build:
@@ -58,21 +49,24 @@ jobs:
         uses: builtin:checkout
 
       - name: Configure Rust directories
+        # Cross remote does not traverse hidden directories under /root.
         run: |
           echo "CARGO_HOME=$RUNNER_TEMP/cargo" >> "$GITHUB_ENV"
           echo "RUSTUP_HOME=$RUNNER_TEMP/rustup" >> "$GITHUB_ENV"
           echo "$RUNNER_TEMP/cargo/bin" >> "$GITHUB_PATH"
 
-      - name: Install Rust toolchain
+      - name: Install standard Rust toolchain
         uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
         with:
-          toolchain: ${{ (inputs.build_mode == 'nightly-experiments' || startsWith(matrix.target, 'mips')) && 'nightly' || 'stable' }}
+          toolchain: ${{ startsWith(matrix.target, 'mips') && 'nightly' || 'stable' }}
           cache: false
           build-warnings: warn
 
-      - name: Install nightly standard library sources
+      - name: Install nightly toolchain and standard library sources
-        if: inputs.build_mode == 'nightly-experiments'
+        run: |
-        run: rustup component add rust-src --toolchain nightly
+          rustup toolchain install nightly \
+            --profile minimal \
+            --component rust-src
 
       - name: Install cross and binary tools
         run: |
@@ -91,7 +85,7 @@ jobs:
 
       - name: Build, verify, package, and compare
         env:
-          # MIPS std needs CRT objects from the cross GCC toolchain.
+          # MIPS build-std needs cross GCC's CRT objects.
           RUSTFLAGS: ${{ startsWith(matrix.target, 'mips') && '-C target-feature=+crt-static -C link-self-contained=no' || '-C target-feature=+crt-static' }}
           CROSS_REMOTE: "true"
           CROSS_REMOTE_COPY_FULL_TARGET_DIR: ${{ startsWith(matrix.target, 'mips') && 'true' || 'false' }}
@@ -101,29 +95,29 @@ jobs:
           declare -A raw_size
           declare -A stripped_size
           declare -A compressed_size
-          declare -a variants
 
           mkdir -p dist
 
-          cross_cmd=(cross)
+          # MIPS requires nightly build-std via Cross.toml.
-          if [[ "$BUILD_MODE" == "nightly-experiments" ]]; then
+          # Every other standard build uses stable.
-            cross_cmd+=(+nightly)
+          standard_toolchain=stable
+          if [[ "$TARGET" == mips* ]]; then
+            standard_toolchain=nightly
           fi
 
           build_variant() {
             local variant="$1"
-            local features="$2"
+            local toolchain="$2"
-            shift 2
+            local features="$3"
+            shift 3
 
             local binary="target/${RUST_TARGET}/release/irtt-client"
             local directory="dist/${variant}"
             local artifact="dist/irtt-client-${TARGET}-${variant}.tar.gz"
 
-            echo "::group::Build ${variant} (${features})"
+            echo "::group::Build ${variant} (${toolchain}, ${features})"
 
-            # Additional arguments allow individual variants to
+            cross "+${toolchain}" build \
-            # customize build-std, std features and panic behavior.
-            "${cross_cmd[@]}" build \
               --release \
               --locked \
               --target "$RUST_TARGET" \
@@ -133,8 +127,7 @@ jobs:
               --features "$features" \
               "$@"
 
-            # Check dynamic linking without relying on pipeline
+            # Reject dynamically linked executables.
-            # behavior under pipefail.
             readelf --program-headers "$binary" > /tmp/program-headers.txt
             readelf --dynamic "$binary" > /tmp/dynamic-section.txt
 
@@ -154,11 +147,10 @@ jobs:
               stat -c %s "$directory/irtt-client"
             )
 
+            # Each archive contains an executable named irtt-client.
             tar -czf "$artifact" -C "$directory" irtt-client
             compressed_size[$variant]=$(stat -c %s "$artifact")
 
-            variants+=("$variant")
-
             echo "::endgroup::"
           }
 
@@ -166,7 +158,7 @@ jobs:
             numfmt --to=iec-i --suffix=B --format='%.1f' "$1"
           }
 
-          # Positive means larger than baseline; negative means smaller.
+          # Negative means smaller than the reference binary.
           delta() {
             awk -v base="$1" -v current="$2" 'BEGIN {
               if (base == 0) {
@@ -177,105 +169,138 @@ jobs:
             }'
           }
 
-          reduction() {
+          print_row() {
-            awk -v full="$1" -v minimal="$2" 'BEGIN {
+            local variant="$1"
-              if (full == 0) {
+            local label="$2"
-                printf "N/A"
+            local baseline="$3"
-              } else {
+            local comparison
-                printf "%.1f%%", 100 * (full - minimal) / full
+
-              }
+            if [[ "$variant" == "$baseline" ]]; then
-            }'
+              comparison="Baseline"
+            else
+              comparison=$(delta \
+                "${compressed_size[$baseline]}" \
+                "${compressed_size[$variant]}")
+            fi
+
+            printf '| %s | %s | %s | %s | %s |\n' \
+              "$label" \
+              "$(human "${raw_size[$variant]}")" \
+              "$(human "${stripped_size[$variant]}")" \
+              "$(human "${compressed_size[$variant]}")" \
+              "$comparison"
           }
 
-          # Standard builds preserve the existing toolchain policy:
+          # ---------------------------------------------------------
-          # stable everywhere except MIPS, which requires nightly.
+          # Standard builds: stable except MIPS.
-          #
+          # ---------------------------------------------------------
-          # Experimental mode uses nightly for every variant so
-          # compiler-version differences don't affect comparisons.
 
+          full_features=client
           if [[ "$HAS_STATS_FEATURE" == "true" ]]; then
-            build_variant full "client,stats"
+            full_features="client,stats"
-            build_variant minimal "client"
+          fi
-            baseline="minimal"
+
+          build_variant full "$standard_toolchain" "$full_features"
+
+          standard_baseline=full
+          if [[ "$HAS_STATS_FEATURE" == "true" ]]; then
+            build_variant minimal "$standard_toolchain" client
+            standard_baseline=minimal
+          fi
+
+          # ---------------------------------------------------------
+          # Nightly baseline: identical compiler for all experiments.
+          #
+          # MIPS already uses nightly for standard builds, so reuse
+          # those binaries rather than compiling them twice.
+          # ---------------------------------------------------------
+
+          if [[ "$standard_toolchain" == "nightly" ]]; then
+            nightly_full=full
+            nightly_baseline="$standard_baseline"
           else
-            # Compatibility with main before stats feature gating.
+            nightly_full=nightly-full
-            build_variant full "client"
+            build_variant nightly-full nightly "$full_features"
-            baseline="full"
+
+            nightly_baseline=nightly-full
+            if [[ "$HAS_STATS_FEATURE" == "true" ]]; then
+              build_variant nightly-minimal nightly client
+              nightly_baseline=nightly-minimal
+            fi
           fi
 
-          if [[ "$BUILD_MODE" == "nightly-experiments" ]]; then
+          # ---------------------------------------------------------
-            # Existing Cross.toml already rebuilds std on MIPS.
+          # Nightly size experiments, always enabled.
-            # On other targets, the normal builds use prebuilt std.
+          # ---------------------------------------------------------
 
-            build_variant rebuilt-std "client" \
+          # Rebuild std with the ordinary std feature set.
-              -Z build-std
+          build_variant rebuilt-std nightly client \
+            -Z build-std
 
-            # Rebuild std without backtrace support, retaining
+          # Rebuild std without backtrace support.
-            # normal panic unwinding.
+          # Retain normal panic unwinding.
-            build_variant no-backtrace "client" \
+          build_variant no-backtrace nightly client \
-              -Z build-std \
+            -Z build-std \
-              -Z build-std-features=panic-unwind
+            -Z build-std-features=panic-unwind
 
-            # Most aggressive experiment: no unwinding, panic
+          # Aggressive option: terminate immediately on panic.
-            # reporting, or std backtrace support.
+          build_variant immediate-abort nightly client \
-            build_variant immediate-abort "client" \
+            -Z panic-immediate-abort \
-              -Z panic-immediate-abort \
+            -Z build-std \
-              -Z build-std \
+            -Z build-std-features= \
-              -Z build-std-features= \
+            --config 'profile.release.panic="immediate-abort"'
-              --config 'profile.release.panic="immediate-abort"'
+
-          fi
+          # ---------------------------------------------------------
+          # Job summary.
+          # ---------------------------------------------------------
 
           {
             echo "### irtt-client: ${TARGET}"
             echo
-            echo "Build mode: \`${BUILD_MODE}\`"
+
+            echo "#### Standard builds"
+            echo
+            echo "Toolchain: \`${standard_toolchain}\`"
             echo
             echo '| Variant | Unstripped | Stripped | Compressed | Compressed vs baseline |'
             echo '|:--|--:|--:|--:|--:|'
 
-            for variant in "${variants[@]}"; do
+            print_row full "Full" "$standard_baseline"
-              if [[ "$variant" == "$baseline" ]]; then
-                comparison="Baseline"
-              else
-                comparison=$(delta \
-                  "${compressed_size[$baseline]}" \
-                  "${compressed_size[$variant]}")
-              fi
-
-              printf '| %s | %s | %s | %s | %s |\n' \
-                "$variant" \
-                "$(human "${raw_size[$variant]}")" \
-                "$(human "${stripped_size[$variant]}")" \
-                "$(human "${compressed_size[$variant]}")" \
-                "$comparison"
-            done
 
             if [[ "$HAS_STATS_FEATURE" == "true" ]]; then
-              echo
+              print_row minimal "Minimal" "$standard_baseline"
-              echo '#### Full vs minimal'
-              echo
-              echo '| Unstripped reduction | Stripped reduction | Compressed reduction |'
-              echo '|--:|--:|--:|'
-
-              printf '| %s | %s | %s |\n' \
-                "$(reduction "${raw_size[full]}" "${raw_size[minimal]}")" \
-                "$(reduction "${stripped_size[full]}" "${stripped_size[minimal]}")" \
-                "$(reduction "${compressed_size[full]}" "${compressed_size[minimal]}")"
-            else
-              echo
-              echo "The stats feature is not available; client includes statistics."
             fi
 
-            if [[ "$BUILD_MODE" == "nightly-experiments" ]]; then
+            echo
+            echo "#### Nightly experiments"
+            echo
+            echo '| Variant | Unstripped | Stripped | Compressed | Compressed vs baseline |'
+            echo '|:--|--:|--:|--:|--:|'
+
+            print_row "$nightly_full" "Nightly full" "$nightly_baseline"
+
+            if [[ "$HAS_STATS_FEATURE" == "true" ]]; then
+              print_row "$nightly_baseline" "Nightly minimal" "$nightly_baseline"
+            fi
+
+            print_row rebuilt-std "Rebuilt std" "$nightly_baseline"
+            print_row no-backtrace "No backtrace" "$nightly_baseline"
+            print_row immediate-abort "Immediate abort" "$nightly_baseline"
+
+            if [[ "$standard_toolchain" == "stable" ]]; then
               echo
-              echo '#### Experiment details'
+              echo "Nightly vs stable baseline (compressed): $(delta \
+                "${compressed_size[$standard_baseline]}" \
+                "${compressed_size[$nightly_baseline]}")"
+            else
               echo
-              echo '- `rebuilt-std`: nightly `-Z build-std`, default std features'
+              echo "MIPS: standard and nightly baselines are identical."
-              echo '- `no-backtrace`: rebuilt std with `panic-unwind` only'
+              echo "Cross.toml already enables build-std for these targets."
-              echo '- `immediate-abort`: rebuilt std with immediate panic termination'
+            fi
+
+            if [[ "$HAS_STATS_FEATURE" != "true" ]]; then
               echo
-              echo 'MIPS already uses build-std through Cross.toml.'
+              echo "Statistics feature not detected; client includes statistics."
-              echo 'All measurements use the same target and nightly toolchain.'
             fi
           } >> "$GITHUB_STEP_SUMMARY"