perf: use sendfile(2) for snapshot serving#293
Merged
joshfriend merged 1 commit intomainfrom May 5, 2026
Merged
Conversation
![chatgpt-codex-connector[bot]](https://avatars.githubusercontent.com/in/1144995?s=60&v=4){kind=small}
There was a problem hiding this comment.
💡 Codex Review
Here are some automated review suggestions for this pull request.
Reviewed commit: a07b3bf674
ℹ️ About Codex in GitHub
Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you
- Open a pull request for review
- Mark a draft as ready
- Comment "@codex review".
If Codex has suggestions, it will comment; otherwise it will react with 👍.
Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".
joshfriend
force-pushed
the
jfriend/sendfile-snapshot-serving
branch
from
a07b3bf to
bff6015
Compare
Replace io.Copy with http.ServeContent when serving cached snapshots from disk. When the cache returns an *os.File, ServeContent uses the sendfile syscall for zero-copy transfer and automatically sets Content-Length, enabling HTTP Range request support. Localhost benchmark: 348 MB/s → 3,050 MB/s (~8.8x improvement).
joshfriend
force-pushed
the
jfriend/sendfile-snapshot-serving
branch
from
bff6015 to
c8cb99b
Compare
alecthomas
approved these changes
May 5, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Use
http.ServeContentinstead ofio.Copywhen serving cached snapshots from disk. When the disk cache returns an*os.File,ServeContentenables thesendfile(2)syscall for zero-copy transfer and automatically setsContent-Length. This also enables HTTP Range request support for free.Localhost benchmark on m5d.16xlarge: 348 MB/s → 3,050 MB/s (~8.8x).