Add options to set BlockProfileRate and MutexProfileFraction

Signed-off-by: Jakub Sztandera <kubuxu@protocol.ai>

cmd/lotus/pprof.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"net/http"
+	"strconv"
+)
+
+func handleFractionOpt(name string, setter func(int)) http.HandlerFunc {
+	return func(rw http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			http.Error(rw, "only POST allowed", http.StatusMethodNotAllowed)
+			return
+		}
+		if err := r.ParseForm(); err != nil {
+			http.Error(rw, err.Error(), http.StatusBadRequest)
+			return
+		}
+
+		asfr := r.Form.Get("x")
+		if len(asfr) == 0 {
+			http.Error(rw, "parameter 'x' must be set", http.StatusBadRequest)
+			return
+		}
+
+		fr, err := strconv.Atoi(asfr)
+		if err != nil {
+			http.Error(rw, err.Error(), http.StatusBadRequest)
+			return
+		}
+		log.Infof("setting %s to %d", name, fr)
+		setter(fr)
+	}
+}

cmd/lotus/rpc.go

@@ -7,6 +7,7 @@ import (
 	_ "net/http/pprof"
 	"os"
 	"os/signal"
+	"runtime"
 	"syscall"
 
 	"github.com/ipfs/go-cid"
@@ -54,6 +55,10 @@ func serveRPC(a api.FullNode, stop node.StopFunc, addr multiaddr.Multiaddr, shut
 	}
 
 	http.Handle("/debug/metrics", exporter)
+	http.Handle("/debug/pprof-set/block", handleFractionOpt("BlockProfileRate", runtime.SetBlockProfileRate))
+	http.Handle("/debug/pprof-set/mutex", handleFractionOpt("MutexProfileFraction",
+		func(x int) { runtime.SetMutexProfileFraction(x) },
+	))
 
 	lst, err := manet.Listen(addr)
 	if err != nil {