Use a pool for write profiles

Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>

pkg/profiler/profiler.go

@@ -97,6 +97,8 @@ type CgroupProfiler struct {
 
 	target            model.LabelSet
 	profilingDuration time.Duration
+
+	profilePool sync.Pool
 }
 
 func NewCgroupProfiler(
@@ -133,6 +135,11 @@ func NewCgroupProfiler(
 				ConstLabels: map[string]string{"target": target.String()},
 			},
 			[]string{"type"}),
+		profilePool: sync.Pool{
+			New: func() interface{} {
+				return bytes.NewBuffer(nil)
+			},
+		},
 	}
 }
 
@@ -341,8 +348,13 @@ func (p *CgroupProfiler) profileLoop(ctx context.Context, captureTime time.Time)
 			level.Error(p.logger).Log("msg", "get value and delete batch", "err", err)
 		}
 	}
+	// TODO(kakkoyun): Remove when error handling with eBPF map batch operations is fixed.
 	if len(values) == 0 {
-		return err
+		const msg = "get value and delete batch, nothing received"
+		if err != nil {
+			return fmt.Errorf(msg+": %w", err)
+		}
+		return errors.New(msg)
 	}
 
 	for i, key := range p.countKeys {
@@ -573,7 +585,11 @@ func (p *CgroupProfiler) normalizeAddress(m *profile.Mapping, pid uint32, addr u
 }
 
 func (p *CgroupProfiler) sendProfile(ctx context.Context, prof *profile.Profile) error {
-	buf := bytes.NewBuffer(nil)
+	buf := p.profilePool.Get().(*bytes.Buffer)
+	defer func() {
+		buf.Reset()
+		p.profilePool.Put(buf)
+	}()
 	if err := prof.Write(buf); err != nil {
 		return err
 	}