From 09a31fa910fb3fe339dd9a60987abfd6aff2f9c0 Mon Sep 17 00:00:00 2001
From: Jarek Kowalski <jaak@jkowalski.net>
Date: Sat, 24 Aug 2019 11:58:08 -0700
Subject: [PATCH] =?UTF-8?q?cli:=20added=20-=E2=80=93track-memory-usage=20f?=
 =?UTF-8?q?lag=20that=20periodically=20logs=20memory=20usage?=
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---
 cli/app.go             |  3 +++
 cli/memory_tracking.go | 53 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 cli/memory_tracking.go

diff --git a/cli/app.go b/cli/app.go
index dfea4055c..443d46411 100644
--- a/cli/app.go
+++ b/cli/app.go
@@ -57,6 +57,9 @@ func serverAction(act func(ctx context.Context, cli *serverapi.Client) error) fu
 func repositoryAction(act func(ctx context.Context, rep *repo.Repository) error) func(ctx *kingpin.ParseContext) error {
 	return func(kpc *kingpin.ParseContext) error {
 		return withProfiling(func() error {
+			startMemoryTracking()
+			defer finishMemoryTracking()
+
 			ctx := context.Background()
 			ctx = content.UsingContentCache(ctx, *enableCaching)
 			ctx = content.UsingListCache(ctx, *enableListCaching)
diff --git a/cli/memory_tracking.go b/cli/memory_tracking.go
new file mode 100644
index 000000000..53c1e108d
--- /dev/null
+++ b/cli/memory_tracking.go
@@ -0,0 +1,53 @@
+package cli
+
+import (
+	"runtime"
+	"sync"
+	"time"
+
+	"github.com/kopia/kopia/internal/kopialogging"
+)
+
+var trackMemoryUsage = app.Flag("track-memory-usage", "Periodically force GC and log current memory usage").Hidden().Duration()
+
+var memlog = kopialogging.Logger("kopia/memory")
+
+var (
+	memoryTrackerMutex            sync.Mutex
+	lastHeapUsage, lastStackInUse uint64
+	maxHeapUsage, maxStackInUse   uint64
+)
+
+func dumpMemoryUsage() {
+	runtime.GC()
+	var ms runtime.MemStats
+	runtime.ReadMemStats(&ms)
+
+	memoryTrackerMutex.Lock()
+	defer memoryTrackerMutex.Unlock()
+	memlog.Debugf("in use heap %v (delta %v max %v) stack %v (delta %v max %v)", ms.HeapInuse, int64(ms.HeapInuse-lastHeapUsage), maxHeapUsage, ms.StackInuse, int64(ms.StackInuse-lastStackInUse), maxStackInUse)
+	if ms.HeapInuse > maxHeapUsage {
+		maxHeapUsage = ms.HeapInuse
+	}
+	if ms.StackInuse > maxStackInUse {
+		maxStackInUse = ms.StackInuse
+	}
+	lastHeapUsage = ms.HeapInuse
+	lastStackInUse = ms.StackInuse
+}
+
+func startMemoryTracking() {
+	if *trackMemoryUsage > 0 {
+
+		go func() {
+			for {
+				dumpMemoryUsage()
+				time.Sleep(*trackMemoryUsage)
+			}
+		}()
+	}
+}
+
+func finishMemoryTracking() {
+	dumpMemoryUsage()
+}