Azeem Shaik
c6f3347870
# Objective Opening a diff against a heavily drifted branch sits on a spinner until every changed file has loaded. Blob reads were serialized through the git job queue and enqueued in `open_buffer` completion order rather than path order, so the blob for the first excerpt could be hundreds of jobs deep. ## Solution 1. `load_blob_content` skips the job queue — blobs are content-addressed, so the read doesn't depend on the status snapshot. 2. `DiffBuffer::load` is a lazy future instead of an eagerly-spawned `Task`, so the consumer picks the concurrency. 3. `DiffMultibuffer` drives those loads through `buffered(16)`. All three are needed: dropping the queue without bounding forks thousands of `cat-file` processes, and bounding without dropping it still serializes. Trust handling is unaffected, since the untrusted-repo flags are applied in `GitBinary::build_command` rather than by the queue. Worth noting that `handle_get_blob_content` is remote-reachable, so a guest can now put up to 16 `cat-file` processes on the host instead of queueing them. ## Testing Added `project_diff::tests::test_excerpts_are_ordered_by_path`, which pins excerpt order to `PathKey` rather than to load completion order, using more files than the concurrency limit and several executor seeds. Green: `cargo test -p git_ui --lib` (131), `cargo test -p project --lib git_store` (11), `./script/clippy`. Not tested against a remote or collab project, which is where the `handle_get_blob_content` change actually matters. ### Numbers Zed repo against a base ~3000 commits back: 2346 changed files, 1794 with a blob at the merge base. Warm cache, one `cat-file` process per blob, best of two runs at each concurrency. | concurrency | total | per blob | speedup | |---|---|---|---| | 1 (previous behaviour) | 77.25s | 43.1ms | 1.00x | | 2 | 17.74s | 9.9ms | 4.35x | | 4 | 10.05s | 5.6ms | 7.69x | | 8 | 7.34s | 4.1ms | 10.52x | | 16 (this change) | 6.63s | 3.7ms | 11.65x | | 32 | 6.59s | 3.7ms | 11.73x | | 64 | 7.14s | 4.0ms | 10.82x | 16 is where the curve flattens: 32 buys another 0.7% and 64 regresses, so there's nothing above it worth the extra in-flight buffers or the extra concurrent processes on a host serving a remote peer. At one blob at a time the first excerpt waits at an arbitrary position in a 1794-deep queue, so roughly 38s on average, which lines up with the 45s full load in the recording below. It's now in the first batch. ## Self-Review Checklist: - [x] I've reviewed my own diff for quality, security, and reliability - [x] Unsafe blocks (if any) have justifying comments — none added - [x] The content adheres to Zed's UI standards — no UI changes - [x] Tests cover the new/changed behavior - [x] Performance impact has been considered and is acceptable ## Showcase Opening a branch diff against a base ~3000 commits back, 2346 changed files. Both clips are cut to 15s to keep the file size down — the before run took 45s to finish loading. **Before** https://github.com/user-attachments/assets/d9475de8-ddd3-48a0-99e2-042a2f655b42 **After** https://github.com/user-attachments/assets/0bf0e73d-0fac-4c2a-9749-71fee376f260 --- Release Notes: - Improved how quickly a branch diff shows its first changes when the branch has drifted a long way from its base
Zed Server
This crate is what we run at https://collab.zed.dev.
It contains our back-end logic for collaboration, to which we connect from the Zed client via a websocket after authenticating via https://zed.dev, which is a separate repo running on Vercel.
Local Development
Database setup
Before you can run the collab server locally, you'll need to set up a zed Postgres database. Follow the steps sequentially:
- Ensure you have postgres installed. If not, install with
brew install postgresql@15. - Follow the steps on Brew's formula and verify your
$PATHcontains/opt/homebrew/opt/postgresql@15/bin. - If you hadn't done it before, create the
postgresuser withcreateuser -s postgres. - You are now ready to run the
bootstrapscript:
script/bootstrap
This script will set up the zed Postgres database, and populate it with some users. It requires internet access, because it fetches some users from the GitHub API.
The script will create several admin users, who you'll sign in as by default when developing locally. The GitHub logins for the default users are specified in the seed.default.json file.
To use a different set of admin users, create crates/collab/seed.json.
{
"admins": ["yourgithubhere"],
"channels": ["zed"]
}
Testing collaborative features locally
In one terminal, run Zed's collaboration server and the livekit dev server:
foreman start
In a second terminal, run two or more instances of Zed.
script/zed-local -2
This script starts one to four instances of Zed, depending on the -2, -3 or -4 flags. Each instance will be connected to the local collab server, signed in as a different user from seed.json or seed.default.json.
Deployment
We run two instances of collab:
- Staging (https://staging-collab.zed.dev)
- Production (https://collab.zed.dev)
Both of these run on the Kubernetes cluster hosted in Digital Ocean.
Deployment is triggered by pushing to the collab-staging (or collab-production) tag in GitHub. The best way to do this is:
./script/deploy-collab staging./script/deploy-collab production
You can tell what is currently deployed with ./script/what-is-deployed.