Pull request 1805: imp-pprof

Merge in DNS/adguard-home from imp-pprof to master

Squashed commit of the following:

commit 2d56e0820fd26720c87978d0096405257100f3f3
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Apr 6 15:10:12 2023 +0300

    home: imp rate

commit 97611a26e224f354d42ea16f3193c6cb72de3a48
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Apr 6 15:03:33 2023 +0300

    home: imp pprof block, mutex profiles

CHANGELOG.md

@@ -25,6 +25,7 @@ NOTE: Add new changes BELOW THIS COMMENT.
 
 ### Added
 
+- Better profiling information when `debug_pprof` is set to `true`.
 - IPv6 support in Safe Search for some services.
 - The ability to make bootstrap DNS lookups prefer IPv6 addresses to IPv4 ones
   using the new `dns.bootstrap_prefer_ipv6` configuration file property

internal/home/home.go

@@ -9,7 +9,6 @@ import (
 	"io/fs"
 	"net"
 	"net/http"
-	"net/http/pprof"
 	"net/netip"
 	"net/url"
 	"os"
@@ -470,26 +469,8 @@ func run(opts options, clientBuildFS fs.FS) {
 		fatalOnError(err)
 
 		if config.DebugPProf {
-			mux := http.NewServeMux()
-			mux.HandleFunc("/debug/pprof/", pprof.Index)
-			mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
-			mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
-			mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
-			mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
-
-			// See profileSupportsDelta in src/net/http/pprof/pprof.go.
-			mux.Handle("/debug/pprof/allocs", pprof.Handler("allocs"))
-			mux.Handle("/debug/pprof/block", pprof.Handler("block"))
-			mux.Handle("/debug/pprof/goroutine", pprof.Handler("goroutine"))
-			mux.Handle("/debug/pprof/heap", pprof.Handler("heap"))
-			mux.Handle("/debug/pprof/mutex", pprof.Handler("mutex"))
-			mux.Handle("/debug/pprof/threadcreate", pprof.Handler("threadcreate"))
-
-			go func() {
-				log.Info("pprof: listening on localhost:6060")
-				lerr := http.ListenAndServe("localhost:6060", mux)
-				log.Error("Error while running the pprof server: %s", lerr)
-			}()
+			// TODO(a.garipov): Make the address configurable.
+			startPprof("localhost:6060")
 		}
 	}
 

internal/home/pprof.go

@@ -0,0 +1,39 @@
+package home
+
+import (
+	"net/http"
+	"net/http/pprof"
+	"runtime"
+
+	"github.com/AdguardTeam/golibs/log"
+)
+
+// startPprof launches the debug and profiling server on addr.
+func startPprof(addr string) {
+	runtime.SetBlockProfileRate(1)
+	runtime.SetMutexProfileFraction(1)
+
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("/debug/pprof/", pprof.Index)
+	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
+	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
+
+	// See profileSupportsDelta in src/net/http/pprof/pprof.go.
+	mux.Handle("/debug/pprof/allocs", pprof.Handler("allocs"))
+	mux.Handle("/debug/pprof/block", pprof.Handler("block"))
+	mux.Handle("/debug/pprof/goroutine", pprof.Handler("goroutine"))
+	mux.Handle("/debug/pprof/heap", pprof.Handler("heap"))
+	mux.Handle("/debug/pprof/mutex", pprof.Handler("mutex"))
+	mux.Handle("/debug/pprof/threadcreate", pprof.Handler("threadcreate"))
+
+	go func() {
+		defer log.OnPanic("pprof server")
+
+		log.Info("pprof: listening on %q", addr)
+		err := http.ListenAndServe(addr, mux)
+		log.Info("pprof server errors: %v", err)
+	}()
+}