ci: Run benchmarks with Ethernet and max MTUs

.github/workflows/bench.yml

@@ -87,8 +87,10 @@ jobs:
           #
           # Run all benchmarks at elevated priority.
           taskset -c 0 nice -n -20 cargo "+$TOOLCHAIN" bench --workspace --exclude neqo-bin --features bench -- --noplot | tee results.txt
-          nice -n -20 cargo "+$TOOLCHAIN" bench --package neqo-bin --features bench -- --noplot | tee -a results.txt
-
+          for MTU in 1500 65536; do
+            sudo ip link set dev lo mtu "$MTU"
+            MTU=$MTU nice -n -20 cargo "+$TOOLCHAIN" bench --package neqo-bin --features bench -- --noplot | tee -a results.txt
+          done
 
       # Compare various configurations of neqo against msquic, and gather perf data
       # during the hyperfine runs.
@@ -132,50 +134,57 @@ jobs:
             fi
           }
 
-          for server in msquic neqo; do
-            for client in msquic neqo; do
-              # msquic doesn't let us configure the congestion control or pacing.
-              if [ "$client" == "msquic" ] && [ "$server" == "msquic" ]; then
-                cc_opt=("")
-                pacing_opt=("")
-              else
-                cc_opt=("reno" "cubic")
-                pacing_opt=("on" "")
-              fi
-              for cc in "${cc_opt[@]}"; do
-                for pacing in "${pacing_opt[@]}"; do
-                  # Make a tag string for this test, for the results.
-                  TAG="$client,$server,$cc,$pacing"
-                  echo "Running benchmarks for $TAG" | tee -a comparison.txt
-                  transmogrify "${server_cmd[$server]}" "$cc" "$pacing"
-                  # shellcheck disable=SC2086
-                  taskset -c 0 nice -n -20 \
-                    perf $PERF_OPT -o "$client-$server$EXT.server.perf" $CMD &
-                  PID=$!
-                  transmogrify "${client_cmd[$client]}" "$cc" "$pacing"
-                  # shellcheck disable=SC2086
-                  taskset -c 1 nice -n -20 \
-                    perf $PERF_OPT -o "$client-$server$EXT.client.perf" \
-                      hyperfine -N --output null -w 1 -s "sleep 1" -n "$TAG" -u millisecond --export-markdown step.md "$CMD" |
-                      tee -a comparison.txt
-                  echo >> comparison.txt
-                  kill $PID
-                  cat step.md >> steps.md
-                  # Sanity check the size of the last retrieved file.
-                  [ "$(wc -c <"$SIZE")" -eq "$SIZE" ] || exit 1
+          # See https://github.com/microsoft/msquic/issues/4618#issuecomment-2422611592
+          for mtu in 1504 65536; do
+            sudo ip link set dev lo mtu "$mtu"
+            for server in msquic neqo; do
+              for client in msquic neqo; do
+                # msquic doesn't let us configure the congestion control or pacing.
+                if [ "$client" == "msquic" ] && [ "$server" == "msquic" ]; then
+                  cc_opt=("")
+                  pacing_opt=("")
+                else
+                  cc_opt=("reno" "cubic")
+                  pacing_opt=("on" "")
+                fi
+                for cc in "${cc_opt[@]}"; do
+                  for pacing in "${pacing_opt[@]}"; do
+                    # Make a tag string for this test, for the results.
+                    TAG="$client,$server,$cc,$pacing,$mtu"
+                    echo "Running benchmarks for $TAG" | tee -a comparison.txt
+                    transmogrify "${server_cmd[$server]}" "$cc" "$pacing"
+                    # shellcheck disable=SC2086
+                    taskset -c 0 nice -n -20 \
+                      perf $PERF_OPT -o "$client-$server$EXT.server.perf" $CMD &
+                    PID=$!
+                    transmogrify "${client_cmd[$client]}" "$cc" "$pacing"
+                    # shellcheck disable=SC2086
+                    taskset -c 1 nice -n -20 \
+                      perf $PERF_OPT -o "$client-$server$EXT.client.perf" \
+                        hyperfine -N --output null -w 1 -s "sleep 1" -n "$TAG" -u millisecond --export-markdown step.md "$CMD" |
+                        tee -a comparison.txt
+                    echo >> comparison.txt
+                    kill $PID
+                    cat step.md >> steps.md
+                    # Sanity check the size of the last retrieved file.
+                    [ "$(wc -c <"$SIZE")" -eq "$SIZE" ] || exit 1
+                  done
                 done
               done
             done
           done
           # Merge the results tables generated by hyperfine into a single table.
           echo "Transfer of $SIZE bytes over loopback." > comparison.md
           awk '(!/^\| Command/ || !c++) && (!/^\|:/ || !d++)' < steps.md |\
-            sed -E 's/`//g; s/^\|:/\|:---\|:---\|:---\|:/g; s/,/ \| /g; s/^\| Command/\| Client \| Server \| CC \| Pacing/g' >> comparison.md
+            sed -E 's/`//g; s/^\|:/\|:---\|:---\|:---\|:---\|:/g; s/,/ \| /g; s/^\| Command/\| Client \| Server \| CC \| Pacing \| MTU/g' >> comparison.md
           rm -r "$TMP"
 
       # Re-enable turboboost, hyperthreading and use powersave governor.
       - name: Restore machine
-        run: sudo /root/bin/unprep.sh
+        run: |
+          sudo /root/bin/unprep.sh
+          # In case the previous test failed:
+          sudo ip link set dev lo mtu 65536
         if: success() || failure() || cancelled()
 
       - name: Post-process perf data

neqo-bin/benches/main.rs

@@ -4,7 +4,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::{path::PathBuf, str::FromStr};
+use std::{env, path::PathBuf, str::FromStr};
 
 use criterion::{criterion_group, criterion_main, BatchSize, Criterion, Throughput};
 use neqo_bin::{client, server};
@@ -20,18 +20,18 @@ fn transfer(c: &mut Criterion) {
     neqo_crypto::init_db(PathBuf::from_str("../test-fixture/db").unwrap()).unwrap();
 
     let done_sender = spawn_server();
-
+    let mtu = env::var("MTU").map_or_else(|_| String::new(), |mtu| format!("/mtu-{mtu}"));
     for Benchmark { name, requests } in [
         Benchmark {
-            name: "1-conn/1-100mb-resp (aka. Download)".to_string(),
+            name: format!("1-conn/1-100mb-resp{mtu} (aka. Download)"),
             requests: vec![100 * 1024 * 1024],
         },
         Benchmark {
-            name: "1-conn/10_000-parallel-1b-resp (aka. RPS)".to_string(),
+            name: format!("1-conn/10_000-parallel-1b-resp{mtu} (aka. RPS)"),
             requests: vec![1; 10_000],
         },
         Benchmark {
-            name: "1-conn/1-1b-resp (aka. HPS)".to_string(),
+            name: format!("1-conn/1-1b-resp{mtu} (aka. HPS)"),
             requests: vec![1; 1],
         },
     ] {

neqo-transport/benches/transfer.rs

@@ -21,7 +21,7 @@ const ZERO: Duration = Duration::from_millis(0);
 const JITTER: Duration = Duration::from_millis(10);
 const TRANSFER_AMOUNT: usize = 1 << 22; // 4Mbyte
 
-fn benchmark_transfer(c: &mut Criterion, label: &str, seed: &Option<impl AsRef<str>>) {
+fn benchmark_transfer(c: &mut Criterion, label: &str, seed: Option<&impl AsRef<str>>) {
     for pacing in [false, true] {
         let mut group = c.benchmark_group(format!("transfer/pacing-{pacing}"));
         // Don't let criterion calculate throughput, as that's based on wall-clock time, not
@@ -63,14 +63,18 @@ fn benchmark_transfer(c: &mut Criterion, label: &str, seed: &Option<impl AsRef<s
 }
 
 fn benchmark_transfer_variable(c: &mut Criterion) {
-    benchmark_transfer(c, "varying-seeds", &std::env::var("SIMULATION_SEED").ok());
+    benchmark_transfer(
+        c,
+        "varying-seeds",
+        std::env::var("SIMULATION_SEED").ok().as_ref(),
+    );
 }
 
 fn benchmark_transfer_fixed(c: &mut Criterion) {
     benchmark_transfer(
         c,
         "same-seed",
-        &Some("62df6933ba1f543cece01db8f27fb2025529b27f93df39e19f006e1db3b8c843"),
+        Some(&"62df6933ba1f543cece01db8f27fb2025529b27f93df39e19f006e1db3b8c843"),
     );
 }