syz-manager: collect avg instance create time

We will also use it to determine when we are ready to schedule programs
that are very likely to crash instances.

1 files changed, 32 insertions, 0 deletions

diff --git a/pkg/stats/avg.go b/pkg/stats/avg.go
new file mode 100644
index 000000000..430ff335b
--- /dev/null
+++ b/pkg/stats/avg.go
@@ -0,0 +1,32 @@
+// Copyright 2024 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package stats
+
+import (
+	"sync"
+	"time"
+)
+
+type AverageParameter interface {
+	time.Duration
+}
+
+type AverageValue[T AverageParameter] struct {
+	mu    sync.Mutex
+	total int64
+	avg   T
+}
+
+func (av *AverageValue[T]) Value() T {
+	av.mu.Lock()
+	defer av.mu.Unlock()
+	return av.avg
+}
+
+func (av *AverageValue[T]) Save(val T) {
+	av.mu.Lock()
+	defer av.mu.Unlock()
+	av.total++
+	av.avg += (val - av.avg) / T(av.total)
+}