main, adds CPU profiling support

manage.sh, release binaries are compiled using the cpu profiling data.

main.go

@@ -12,6 +12,7 @@ import (
 	"path"
 	"path/filepath"
 	"runtime"
+	"runtime/pprof"
 	"slices"
 	"sort"
 	"strconv"
@@ -204,7 +205,7 @@ func die(b bool, msg string) {
 	}
 }
 
-func main() {
+func do() {
 	var err error
 	args := os.Args[1:]
 
@@ -318,3 +319,29 @@ func main() {
 		}
 	}
 }
+
+func do_with_profiling(output_filename string) {
+	f, err := os.Create(output_filename)
+	die(err != nil, "could not create CPU profile")
+	defer f.Close()
+
+	err = pprof.StartCPUProfile(f)
+	die(err != nil, "could not start CPU profile")
+
+	defer pprof.StopCPUProfile()
+
+	do()
+}
+
+func main() {
+	profile := os.Getenv("VAJ_PROFILE")
+	if profile != "" {
+		println("profiling is on")
+		println("---")
+		do_with_profiling("cpu.prof")
+		println("---")
+		println("wrote cpu.prof")
+	} else {
+		do()
+	}
+}

manage.sh

@@ -30,11 +30,13 @@ elif test "$cmd" = "release"; then
     # ld -w is 'disable DWARF generation'
     # -trimpath removes leading paths to source files
     # -v 'verbose'
+    # -pgo 'profile-guided-optimisation' using the cpu profile 'cpu.prof'
     # -o 'output'
     GOOS=linux CGO_ENABLED=0 go build \
         -ldflags="-s -w" \
         -trimpath \
         -v \
+        -pgo cpu.prof \
         -o linux-amd64
     sha256sum linux-amd64 > linux-amd64.sha256
     echo ---