c8d/list: Generate image summary concurrently

[vvoland]

• related to: Image list with containerd store is very slow #47564

- What I did

Add Images benchmark

Added a small benchmark that calls Images with image store containing 10, 100 and 1000 random images. Currently the images are single-platform only.

The images are generated randomly, but a fixed seed is used so the actual testing data will be the same across different executions.

Because the content store is not a real containerd image store but a local implementation, a small delay (500us) is added to each content store method call. This is to simulate a real-world usage where each containerd client call requires a gRPC call.

Generate image summary concurrently

Run imageSummary concurrently to avoid being IO blocked on the containerd gRPC.

- How I did it

- How to verify it

$ go test -bench=. -benchtime 5s -run BenchmarkImageList
goos: linux
goarch: arm64
pkg: github.com/docker/docker/daemon/containerd
-BenchmarkImageList/10-images-6                16         367278667 ns/op
-BenchmarkImageList/100-images-6                8         688544167 ns/op
-BenchmarkImageList/1000-images-6               4        1337588918 ns/op
+BenchmarkImageList/10-images-6               140          42308378 ns/op
+BenchmarkImageList/100-images-6               81          68406268 ns/op
+BenchmarkImageList/1000-images-6              81          90511519 ns/op
PASS

- Description for the changelog

containerd image store: Improve `docker images` performance

- A picture of a cute animal (not mandatory but encouraged)