From d55df9e5fdbc5619a823dc3942ea1c4c96ab3fd3 Mon Sep 17 00:00:00 2001
From: Daniel Hodges <hodges.daniel.scott@gmail.com>
Date: Wed, 12 Feb 2025 07:32:03 -0500
Subject: [PATCH] build: Add script for pgo/lto builds

---
 pgo-lto.sh | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100755 pgo-lto.sh

diff --git a/pgo-lto.sh b/pgo-lto.sh
new file mode 100755
index 000000000..38bf2fa05
--- /dev/null
+++ b/pgo-lto.sh
@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -eou pipefail
+
+PGO_TMPDIR=${1:-/tmp/pgo-data}
+SCHED=${2:-scx_rustland}
+PGO_DUR=${3:-30}
+
+rm -rf "$PGO_TMPDIR"
+mkdir -p "$PGO_TMPDIR"
+
+RUSTFLAGS="-C profile-generate=$PGO_TMPDIR -C link-arg=-lgcov" \
+    cargo build --release --bin "$SCHED"
+
+echo "Running sched to generate PGO"
+for i in {0..3}; do
+	sudo "./target/release/$SCHED" &
+	sleep "$PGO_DUR"
+	sudo kill -9 $! || echo "$SCHED already dead"
+	sleep 1
+done
+
+# Merge the `.profraw` files into a `.profdata` file
+llvm-profdata merge --failure-mode=warn \
+	-o "$PGO_TMPDIR/merged.profdata" \
+	"$PGO_TMPDIR"
+
+# Use the `.profdata` file for guiding optimizations
+RUSTFLAGS="-Cprofile-use=$PGO_TMPDIR/merged.profdata" \
+    cargo build --release --bin "$SCHED"
+