Max Brunsfeld created
Linear:
https://linear.app/zed-industries/issue/Z-2578/zed-launches-very-slow-for-user
I was searching for the cause of a slow startup time reported in the
above issue, and I don't think I found it, but I did find two very
noticeable slow code paths while profiling, and fixed them.
### Notes
1. When starting the JSON language server, we provide it with a JSON
schema for our settings. For the `theme` setting, the JSON schema needs
to read all of the themes in the registry, to generate a list of valid
theme names. Previously, as part of this, we were deserializing each
theme from JSON, which took a lot of CPU. Now, we don't do that.
2. When an FS event occurs within a git repository, we reload the git
status for all entries in that git repository. Previously, we did that
via a separate `libgit2` call per FS entry (including ignored entries,
so many thousands in the case of the `zed` repo). Now we do one
`libgit2` call, asking for all of the statuses. Git carries an index of
all of the files with statuses, so this is fast.
Release Notes:
- Improved the the performance of starting up a JSON language server.
- Improved the performance of handling changes to git repositories, such
as changing branches or committing.crates/fs/src/repository.rs | 1 +
crates/project/src/worktree.rs | 9 +++++----
crates/theme/src/theme_registry.rs | 22 +++++++++++++++++-----
crates/theme/src/theme_settings.rs | 4 ++--
4 files changed, 25 insertions(+), 11 deletions(-)
@@ -33,6 +33,7 @@ pub trait GitRepository: Send {
fn statuses(&self) -> Option<TreeMap<RepoPath, GitFileStatus>>;
fn status(&self, path: &RepoPath) -> Result<Option<GitFileStatus>>;
+
fn branches(&self) -> Result<Vec<Branch>> {
Ok(vec![])
}
@@ -2022,6 +2022,9 @@ impl LocalSnapshot {
) -> Vec<Arc<Path>> {
let mut changes = vec![];
let mut edits = vec![];
+
+ let statuses = repo_ptr.statuses();
+
for mut entry in self
.descendent_entries(false, false, &work_directory.0)
.cloned()
@@ -2029,10 +2032,8 @@ impl LocalSnapshot {
let Ok(repo_path) = entry.path.strip_prefix(&work_directory.0) else {
continue;
};
- let git_file_status = repo_ptr
- .status(&RepoPath(repo_path.into()))
- .log_err()
- .flatten();
+ let repo_path = RepoPath(repo_path.to_path_buf());
+ let git_file_status = statuses.as_ref().and_then(|s| s.get(&repo_path).copied());
if entry.git_status != git_file_status {
entry.git_status = git_file_status;
changes.push(entry.path.clone());
@@ -5,6 +5,7 @@ use parking_lot::Mutex;
use serde::Deserialize;
use serde_json::Value;
use std::{
+ borrow::Cow,
collections::HashMap,
sync::{
atomic::{AtomicUsize, Ordering::SeqCst},
@@ -43,7 +44,7 @@ impl ThemeRegistry {
this
}
- pub fn list(&self, staff: bool) -> impl Iterator<Item = ThemeMeta> + '_ {
+ pub fn list_names(&self, staff: bool) -> impl Iterator<Item = Cow<str>> + '_ {
let mut dirs = self.assets.list("themes/");
if !staff {
@@ -53,10 +54,21 @@ impl ThemeRegistry {
.collect()
}
- dirs.into_iter().filter_map(|path| {
- let filename = path.strip_prefix("themes/")?;
- let theme_name = filename.strip_suffix(".json")?;
- self.get(theme_name).ok().map(|theme| theme.meta.clone())
+ fn get_name(path: &str) -> Option<&str> {
+ path.strip_prefix("themes/")?.strip_suffix(".json")
+ }
+
+ dirs.into_iter().filter_map(|path| match path {
+ Cow::Borrowed(path) => Some(Cow::Borrowed(get_name(path)?)),
+ Cow::Owned(path) => Some(Cow::Owned(get_name(&path)?.to_string())),
+ })
+ }
+
+ pub fn list(&self, staff: bool) -> impl Iterator<Item = ThemeMeta> + '_ {
+ self.list_names(staff).filter_map(|theme_name| {
+ self.get(theme_name.as_ref())
+ .ok()
+ .map(|theme| theme.meta.clone())
})
}
@@ -149,8 +149,8 @@ impl settings::Setting for ThemeSettings {
let mut root_schema = generator.root_schema_for::<ThemeSettingsContent>();
let theme_names = cx
.global::<Arc<ThemeRegistry>>()
- .list(params.staff_mode)
- .map(|theme| Value::String(theme.name.clone()))
+ .list_names(params.staff_mode)
+ .map(|theme_name| Value::String(theme_name.to_string()))
.collect();
let theme_name_schema = SchemaObject {