[client] Debug: dump GUI memory profiles to /tmp/nbgui

Temporary debug patch for the GUI memory consumption investigation. Writes
two snapshots - one at startup, one after 5 minutes - each into its own
/tmp/nbgui/<timestamp>-<pid> directory containing the heap, goroutine and
threadcreate profiles plus a memstats.txt summary.

client/ui/main.go

@@ -80,6 +80,11 @@ func init() {
 
 func main() {
 	daemonAddr, userSetLogFile := parseFlagsAndInitLog()
+
+	// Debug patch, not for release: dumps heap/goroutine profiles to
+	// /tmp/nbgui for the memory consumption investigation.
+	startMemProfiler()
+
 	conn := NewConn(daemonAddr)
 
 	// Without --log-file, the GUI manages a gui-client.log that follows the

client/ui/memprof.go

@@ -0,0 +1,173 @@
+//go:build !android && !ios && !freebsd && !js
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"runtime/pprof"
+	"strings"
+	"time"
+
+	"github.com/shirou/gopsutil/v4/process"
+	log "github.com/sirupsen/logrus"
+)
+
+const memProfDelay = 5 * time.Minute
+
+type memProfileSpec struct {
+	profile string
+	file    string
+	debug   int
+}
+
+var memProfileSpecs = []memProfileSpec{
+	{profile: "heap", file: "heap.pprof", debug: 0},
+	{profile: "heap", file: "heap.txt", debug: 1},
+	{profile: "goroutine", file: "goroutine.txt", debug: 1},
+	{profile: "threadcreate", file: "threadcreate.txt", debug: 1},
+}
+
+var memProfStart = time.Now()
+
+// startMemProfiler dumps two profile snapshots for memory analysis: one at
+// startup and one after memProfDelay, each into its own timestamped directory
+// under memProfBaseDir. Every failure is logged and never stops the GUI.
+func startMemProfiler() {
+	base := memProfBaseDir()
+	log.Infof("memory profiler enabled, writing to %s (snapshots at startup and after %s)", base, memProfDelay)
+
+	go func() {
+		writeMemProfile()
+		time.Sleep(memProfDelay)
+		writeMemProfile()
+	}()
+}
+
+// memProfBaseDir returns the directory holding the snapshot directories.
+func memProfBaseDir() string {
+	if runtime.GOOS == "windows" {
+		return filepath.Join(os.TempDir(), "nbgui")
+	}
+	return "/tmp/nbgui"
+}
+
+// writeMemProfile creates a <timestamp>-<pid> directory and fills it with the
+// runtime profiles and the memory statistics summary.
+func writeMemProfile() {
+	name := fmt.Sprintf("%s-%d", time.Now().Format("20060102-150405"), os.Getpid())
+	dir := filepath.Join(memProfBaseDir(), name)
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		log.Warnf("create memory profile dir %s: %v", dir, err)
+		return
+	}
+
+	// The heap profile reports live objects as of the last collection, so force
+	// one to keep inuse_space from counting garbage that is already unreachable.
+	runtime.GC()
+
+	if err := writeMemStats(filepath.Join(dir, "memstats.txt")); err != nil {
+		log.Warnf("write memory statistics: %v", err)
+	}
+
+	for _, spec := range memProfileSpecs {
+		if err := writeMemProfileFile(spec, filepath.Join(dir, spec.file)); err != nil {
+			log.Warnf("write %s profile: %v", spec.profile, err)
+		}
+	}
+
+	log.Infof("memory profile written to %s", dir)
+}
+
+// writeMemProfileFile writes a single runtime profile to path.
+func writeMemProfileFile(spec memProfileSpec, path string) error {
+	p := pprof.Lookup(spec.profile)
+	if p == nil {
+		return fmt.Errorf("unknown profile %q", spec.profile)
+	}
+
+	f, err := os.Create(path)
+	if err != nil {
+		return fmt.Errorf("create %s: %w", path, err)
+	}
+	defer func() {
+		if err := f.Close(); err != nil {
+			log.Debugf("close %s: %v", path, err)
+		}
+	}()
+
+	if err := p.WriteTo(f, spec.debug); err != nil {
+		return fmt.Errorf("write %s: %w", path, err)
+	}
+	return nil
+}
+
+// writeMemStats dumps the runtime memory statistics next to the process
+// resident set size. A resident set much larger than Sys means the memory sits
+// outside the Go heap (webview, GTK, other cgo allocations), where the pprof
+// profiles cannot see it.
+func writeMemStats(path string) error {
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+
+	var b strings.Builder
+	fmt.Fprintf(&b, "time:           %s\n", time.Now().Format(time.RFC3339))
+	fmt.Fprintf(&b, "uptime:         %s\n", time.Since(memProfStart).Round(time.Second))
+	fmt.Fprintf(&b, "pid:            %d\n", os.Getpid())
+	fmt.Fprintf(&b, "\n")
+
+	rss, vms := processMemory()
+	fmt.Fprintf(&b, "process_rss:    %s\n", rss)
+	fmt.Fprintf(&b, "process_vms:    %s\n", vms)
+	fmt.Fprintf(&b, "\n")
+
+	fmt.Fprintf(&b, "sys:            %s\n", formatMemBytes(m.Sys))
+	fmt.Fprintf(&b, "heap_alloc:     %s\n", formatMemBytes(m.HeapAlloc))
+	fmt.Fprintf(&b, "heap_sys:       %s\n", formatMemBytes(m.HeapSys))
+	fmt.Fprintf(&b, "heap_inuse:     %s\n", formatMemBytes(m.HeapInuse))
+	fmt.Fprintf(&b, "heap_idle:      %s\n", formatMemBytes(m.HeapIdle))
+	fmt.Fprintf(&b, "heap_released:  %s\n", formatMemBytes(m.HeapReleased))
+	fmt.Fprintf(&b, "heap_objects:   %d\n", m.HeapObjects)
+	fmt.Fprintf(&b, "stack_inuse:    %s\n", formatMemBytes(m.StackInuse))
+	fmt.Fprintf(&b, "stack_sys:      %s\n", formatMemBytes(m.StackSys))
+	fmt.Fprintf(&b, "mspan_sys:      %s\n", formatMemBytes(m.MSpanSys))
+	fmt.Fprintf(&b, "mcache_sys:     %s\n", formatMemBytes(m.MCacheSys))
+	fmt.Fprintf(&b, "gc_sys:         %s\n", formatMemBytes(m.GCSys))
+	fmt.Fprintf(&b, "other_sys:      %s\n", formatMemBytes(m.OtherSys))
+	fmt.Fprintf(&b, "next_gc:        %s\n", formatMemBytes(m.NextGC))
+	fmt.Fprintf(&b, "num_gc:         %d\n", m.NumGC)
+	fmt.Fprintf(&b, "\n")
+
+	fmt.Fprintf(&b, "goroutines:     %d\n", runtime.NumGoroutine())
+	fmt.Fprintf(&b, "cgo_calls:      %d\n", runtime.NumCgoCall())
+	fmt.Fprintf(&b, "gomaxprocs:     %d\n", runtime.GOMAXPROCS(0))
+
+	if err := os.WriteFile(path, []byte(b.String()), 0o644); err != nil {
+		return fmt.Errorf("write %s: %w", path, err)
+	}
+	return nil
+}
+
+// processMemory returns the formatted resident and virtual size of this process.
+func processMemory() (string, string) {
+	p, err := process.NewProcess(int32(os.Getpid()))
+	if err != nil {
+		unavailable := fmt.Sprintf("unavailable (%v)", err)
+		return unavailable, unavailable
+	}
+
+	info, err := p.MemoryInfo()
+	if err != nil {
+		unavailable := fmt.Sprintf("unavailable (%v)", err)
+		return unavailable, unavailable
+	}
+
+	return formatMemBytes(info.RSS), formatMemBytes(info.VMS)
+}
+
+// formatMemBytes renders a byte count as megabytes with the raw value kept.
+func formatMemBytes(n uint64) string {
+	return fmt.Sprintf("%8.1f MB (%d bytes)", float64(n)/(1024*1024), n)
+}