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// Copyright Materialize, Inc. and contributors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License in the LICENSE file at the
// root of this repository, or online at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#![doc = include_str!("../README.md")]
use std::collections::BTreeMap;
use std::ffi::CString;
use std::io::BufReader;
use std::os::unix::ffi::OsStrExt;
use std::sync::Arc;
use std::time::Instant;
use internal::parse_jeheap;
use libc::size_t;
use once_cell::sync::Lazy;
use tempfile::NamedTempFile;
use tikv_jemalloc_ctl::raw;
use tokio::sync::Mutex;
pub mod internal;
mod linux;
mod cast;
#[path = "perftools.profiles.rs"]
mod pprof_types;
/// Start times of the profiler.
#[derive(Copy, Clone, Debug)]
pub enum ProfStartTime {
Instant(Instant),
TimeImmemorial,
}
/// Helper struct to simplify building a `string_table` for the pprof format.
#[derive(Default)]
struct StringTable(BTreeMap<String, i64>);
impl StringTable {
fn new() -> Self {
// Element 0 must always be the emtpy string.
let inner = [("".into(), 0)].into();
Self(inner)
}
fn insert(&mut self, s: &str) -> i64 {
if let Some(idx) = self.0.get(s) {
*idx
} else {
let idx = i64::try_from(self.0.len()).expect("must fit");
self.0.insert(s.into(), idx);
idx
}
}
fn finish(self) -> Vec<String> {
let mut vec: Vec<_> = self.0.into_iter().collect();
vec.sort_by_key(|(_, idx)| *idx);
vec.into_iter().map(|(s, _)| s).collect()
}
}
/// Activate jemalloc profiling.
pub async fn activate_jemalloc_profiling() {
let Some(ctl) = PROF_CTL.as_ref() else {
tracing::warn!("jemalloc profiling is disabled and cannot be activated");
return;
};
let mut ctl = ctl.lock().await;
if ctl.activated() {
return;
}
match ctl.activate() {
Ok(()) => tracing::info!("jemalloc profiling activated"),
Err(err) => tracing::warn!("could not activate jemalloc profiling: {err}"),
}
}
/// Deactivate jemalloc profiling.
pub async fn deactivate_jemalloc_profiling() {
let Some(ctl) = PROF_CTL.as_ref() else {
return; // jemalloc not enabled
};
let mut ctl = ctl.lock().await;
if !ctl.activated() {
return;
}
match ctl.deactivate() {
Ok(()) => tracing::info!("jemalloc profiling deactivated"),
Err(err) => tracing::warn!("could not deactivate jemalloc profiling: {err}"),
}
}
/// Per-process singleton for controlling jemalloc profiling.
pub static PROF_CTL: Lazy<Option<Arc<Mutex<JemallocProfCtl>>>> = Lazy::new(|| {
if let Some(ctl) = JemallocProfCtl::get() {
Some(Arc::new(Mutex::new(ctl)))
} else {
None
}
});
/// Metadata about a jemalloc heap profiler.
#[derive(Copy, Clone, Debug)]
pub struct JemallocProfMetadata {
pub start_time: Option<ProfStartTime>,
}
/// A handle to control jemalloc profiling.
#[derive(Debug)]
pub struct JemallocProfCtl {
md: JemallocProfMetadata,
}
impl JemallocProfCtl {
// Creates and returns the global singleton.
fn get() -> Option<Self> {
// SAFETY: "opt.prof" is documented as being readable and returning a bool:
// http://jemalloc.net/jemalloc.3.html#opt.prof
let prof_enabled: bool = unsafe { raw::read(b"opt.prof\0") }.unwrap();
if prof_enabled {
// SAFETY: "opt.prof_active" is documented as being readable and returning a bool:
// http://jemalloc.net/jemalloc.3.html#opt.prof_active
let prof_active: bool = unsafe { raw::read(b"opt.prof_active\0") }.unwrap();
let start_time = if prof_active {
Some(ProfStartTime::TimeImmemorial)
} else {
None
};
let md = JemallocProfMetadata { start_time };
Some(Self { md })
} else {
None
}
}
/// Returns the base 2 logarithm of the sample rate (average interval, in bytes, between allocation samples).
pub fn lg_sample(&self) -> size_t {
// SAFETY: "prof.lg_sample" is documented as being readable and returning size_t:
// https://jemalloc.net/jemalloc.3.html#opt.lg_prof_sample
unsafe { raw::read(b"prof.lg_sample\0") }.unwrap()
}
/// Returns the metadata of the profiler.
pub fn get_md(&self) -> JemallocProfMetadata {
self.md
}
/// Returns whether the profiler is active.
pub fn activated(&self) -> bool {
self.md.start_time.is_some()
}
/// Activate the profiler and if unset, set the start time to the current time.
pub fn activate(&mut self) -> Result<(), tikv_jemalloc_ctl::Error> {
// SAFETY: "prof.active" is documented as being writable and taking a bool:
// http://jemalloc.net/jemalloc.3.html#prof.active
unsafe { raw::write(b"prof.active\0", true) }?;
if self.md.start_time.is_none() {
self.md.start_time = Some(ProfStartTime::Instant(Instant::now()));
}
Ok(())
}
/// Deactivate the profiler.
pub fn deactivate(&mut self) -> Result<(), tikv_jemalloc_ctl::Error> {
// SAFETY: "prof.active" is documented as being writable and taking a bool:
// http://jemalloc.net/jemalloc.3.html#prof.active
unsafe { raw::write(b"prof.active\0", false) }?;
let rate = self.lg_sample();
// SAFETY: "prof.reset" is documented as being writable and taking a size_t:
// http://jemalloc.net/jemalloc.3.html#prof.reset
unsafe { raw::write(b"prof.reset\0", rate) }?;
self.md.start_time = None;
Ok(())
}
/// Dump a profile into a temporary file and return it.
pub fn dump(&mut self) -> anyhow::Result<std::fs::File> {
let f = NamedTempFile::new()?;
let path = CString::new(f.path().as_os_str().as_bytes().to_vec()).unwrap();
// SAFETY: "prof.dump" is documented as being writable and taking a C string as input:
// http://jemalloc.net/jemalloc.3.html#prof.dump
unsafe { raw::write(b"prof.dump\0", path.as_ptr()) }?;
Ok(f.into_file())
}
/// Dump a profile in pprof format (gzipped protobuf) and
/// return a buffer with its contents.
pub fn dump_pprof(&mut self) -> anyhow::Result<Vec<u8>> {
let f = self.dump()?;
let dump_reader = BufReader::new(f);
let profile = parse_jeheap(dump_reader)?;
let pprof = profile.to_pprof(("inuse_space", "bytes"), ("space", "bytes"), None);
Ok(pprof)
}
}