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use once_cell::sync::Lazy;
use std::{
cell::RefCell,
collections::{BTreeMap, HashSet},
io::{stderr, Write},
sync::{
atomic::{AtomicBool, Ordering},
RwLock,
},
time::{Duration, Instant},
};
use crate::tree::{Idx, Tree};
pub fn init() {
let spec = std::env::var("RA_PROFILE").unwrap_or_default();
init_from(&spec);
}
pub fn init_from(spec: &str) {
let filter = if spec.is_empty() { Filter::disabled() } else { Filter::from_spec(spec) };
filter.install();
}
type Label = &'static str;
pub fn span(label: Label) -> ProfileSpan {
assert!(!label.is_empty());
if PROFILING_ENABLED.load(Ordering::Relaxed)
&& PROFILE_STACK.with(|stack| stack.borrow_mut().push(label))
{
ProfileSpan(Some(ProfilerImpl { label, detail: None }))
} else {
ProfileSpan(None)
}
}
pub struct ProfileSpan(Option<ProfilerImpl>);
struct ProfilerImpl {
label: Label,
detail: Option<String>,
}
impl ProfileSpan {
pub fn detail(mut self, detail: impl FnOnce() -> String) -> ProfileSpan {
if let Some(profiler) = &mut self.0 {
profiler.detail = Some(detail())
}
self
}
}
impl Drop for ProfilerImpl {
fn drop(&mut self) {
PROFILE_STACK.with(|it| it.borrow_mut().pop(self.label, self.detail.take()));
}
}
static PROFILING_ENABLED: AtomicBool = AtomicBool::new(false);
static FILTER: Lazy<RwLock<Filter>> = Lazy::new(Default::default);
thread_local!(static PROFILE_STACK: RefCell<ProfileStack> = RefCell::new(ProfileStack::new()));
#[derive(Default, Clone, Debug)]
struct Filter {
depth: usize,
allowed: HashSet<String>,
longer_than: Duration,
version: usize,
}
impl Filter {
fn disabled() -> Filter {
Filter::default()
}
fn from_spec(mut spec: &str) -> Filter {
let longer_than = if let Some(idx) = spec.rfind('>') {
let longer_than = spec[idx + 1..].parse().expect("invalid profile longer_than");
spec = &spec[..idx];
Duration::from_millis(longer_than)
} else {
Duration::new(0, 0)
};
let depth = if let Some(idx) = spec.rfind('@') {
let depth: usize = spec[idx + 1..].parse().expect("invalid profile depth");
spec = &spec[..idx];
depth
} else {
999
};
let allowed =
if spec == "*" { HashSet::new() } else { spec.split('|').map(String::from).collect() };
Filter { depth, allowed, longer_than, version: 0 }
}
fn install(mut self) {
PROFILING_ENABLED.store(self.depth > 0, Ordering::SeqCst);
let mut old = FILTER.write().unwrap();
self.version = old.version + 1;
*old = self;
}
}
struct ProfileStack {
starts: Vec<Instant>,
filter: Filter,
messages: Tree<Message>,
}
#[derive(Default)]
struct Message {
duration: Duration,
label: Label,
detail: Option<String>,
}
impl ProfileStack {
fn new() -> ProfileStack {
ProfileStack { starts: Vec::new(), messages: Tree::default(), filter: Default::default() }
}
fn push(&mut self, label: Label) -> bool {
if self.starts.is_empty() {
if let Ok(f) = FILTER.try_read() {
if f.version > self.filter.version {
self.filter = f.clone();
}
};
}
if self.starts.len() > self.filter.depth {
return false;
}
let allowed = &self.filter.allowed;
if self.starts.is_empty() && !allowed.is_empty() && !allowed.contains(label) {
return false;
}
self.starts.push(Instant::now());
self.messages.start();
true
}
fn pop(&mut self, label: Label, detail: Option<String>) {
let start = self.starts.pop().unwrap();
let duration = start.elapsed();
self.messages.finish(Message { duration, label, detail });
if self.starts.is_empty() {
let longer_than = self.filter.longer_than;
if duration.as_millis() > longer_than.as_millis() {
if let Some(root) = self.messages.root() {
print(&self.messages, root, 0, longer_than, &mut stderr().lock());
}
}
self.messages.clear();
}
}
}
fn print(
tree: &Tree<Message>,
curr: Idx<Message>,
level: u32,
longer_than: Duration,
out: &mut impl Write,
) {
let current_indent = " ".repeat(level as usize);
let detail = tree[curr].detail.as_ref().map(|it| format!(" @ {}", it)).unwrap_or_default();
writeln!(
out,
"{}{:5}ms - {}{}",
current_indent,
tree[curr].duration.as_millis(),
tree[curr].label,
detail,
)
.expect("printing profiling info");
let mut accounted_for = Duration::default();
let mut short_children = BTreeMap::new();
for child in tree.children(curr) {
accounted_for += tree[child].duration;
if tree[child].duration.as_millis() > longer_than.as_millis() {
print(tree, child, level + 1, longer_than, out)
} else {
let (total_duration, cnt) =
short_children.entry(tree[child].label).or_insert((Duration::default(), 0));
*total_duration += tree[child].duration;
*cnt += 1;
}
}
for (child_msg, (duration, count)) in short_children.iter() {
let millis = duration.as_millis();
writeln!(out, " {}{:5}ms - {} ({} calls)", current_indent, millis, child_msg, count)
.expect("printing profiling info");
}
let unaccounted = tree[curr].duration - accounted_for;
if tree.children(curr).next().is_some() && unaccounted > longer_than {
writeln!(out, " {}{:5}ms - ???", current_indent, unaccounted.as_millis())
.expect("printing profiling info");
}
}