## Issue
When pulling images, the download speed appears to be slower compared to
Docker.
I found that parallel chunk generation was being performed during the
layer download process.
While individual chunks allow parallel download operations, the overall
process remains sequential between chunks.
This results less performance when chunks contain both small and large
layers mixed together.
## Changes
Discontinued chunk-based segmentation to enable more efficient parallel
downloads.
## Results(in my local env)
| image | layers | old | new |
| ---|---|---|---|
| node:latest | 12 | 1m15s | 1m10s |
| ghcr.io/norio-nomura/swift_discord_bot:main | 54 | 2m45s | 2m30s |
<details>
<summary>raw terminal log</summary>
```
❯ rm -rf ~/Library/Application\ Support/com.apple.containerization && time bin/cctl_old images pull docker.io/library/node:latest
image pulled
bin/cctl_old images pull docker.io/library/node:latest 42.37s user 6.60s system 64% cpu 1:15.94 total
❯ rm -rf ~/Library/Application\ Support/com.apple.containerization && time bin/cctl_new images pull docker.io/library/node:latest
image pulled
bin/cctl_new images pull docker.io/library/node:latest 42.27s user 6.72s system 69% cpu 1:10.58 total
❯ rm -rf ~/Library/Application\ Support/com.apple.containerization && time bin/cctl_old images pull docker.io/library/node:latest
image pulled
bin/cctl_old images pull docker.io/library/node:latest 45.65s user 7.36s system 70% cpu 1:15.64 total
❯ rm -rf ~/Library/Application\ Support/com.apple.containerization && time bin/cctl_new images pull docker.io/library/node:latest
image pulled
bin/cctl_new images pull docker.io/library/node:latest 39.76s user 6.32s system 65% cpu 1:10.50 total
❯ rm -rf ~/Library/Application\ Support/com.apple.containerization && time bin/cctl_old images pull docker.io/library/node:latest
image pulled
bin/cctl_old images pull docker.io/library/node:latest 42.47s user 6.75s system 65% cpu 1:14.72 total
❯ rm -rf ~/Library/Application\ Support/com.apple.containerization && time bin/cctl_new images pull docker.io/library/node:latest
image pulled
bin/cctl_new images pull docker.io/library/node:latest 42.28s user 6.65s system 69% cpu 1:09.93 total
❯ rm -rf ~/Library/Application\ Support/com.apple.containerization && time bin/cctl_new images pull ghcr.io/norio-nomura/swift_discord_bot:main
image pulled
bin/cctl_new images pull ghcr.io/norio-nomura/swift_discord_bot:main 103.83s user 18.71s system 81% cpu 2:30.02 total
❯ rm -rf ~/Library/Application\ Support/com.apple.containerization && time bin/cctl_old images pull ghcr.io/norio-nomura/swift_discord_bot:main
image pulled
bin/cctl_old images pull ghcr.io/norio-nomura/swift_discord_bot:main 120.79s user 20.70s system 85% cpu 2:45.26 total
```
</details>
<details>
<summary>patch for download only</summary>
```diff
diff --git a/Sources/cctl/ImageCommand.swift b/Sources/cctl/ImageCommand.swift
index 84c5218..4aa4bb8 100644
--- a/Sources/cctl/ImageCommand.swift
+++ b/Sources/cctl/ImageCommand.swift
@@ -127,6 +127,7 @@ extension Application {
}
print("image pulled")
+ return
let tempDir = FileManager.default.uniqueTemporaryDirectory(create: true)
if let platform {
```
</details>
This change adds documentation to quite a few existing public types that
didn't have a blurb before.
Additionally, this fixes a couple things that I think either didn't make
sense when going to document them:
- Rename ConnectionStream to VsockConnectionStream. This type only
functions for vsock connections.
- Deletes NsLock+Closure. This was not used anywhere.
- Rename ContainerizationOCI/Config.swift to ImageConfig.swift.
Signed-off-by: Danny Canter <danny_canter@apple.com>
Dmitry Kovba