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utils: symbolize heap profiles (#10153)

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## Problem

Jemalloc heap profiles aren't symbolized. This is inconvenient, and
doesn't work with Grafana Cloud Profiles.

Resolves #9964.

## Summary of changes

Symbolize the heap profiles in-process, and strip unnecessary cruft.

This uses about 100 MB additional memory to cache the DWARF information,
but I believe this is already the case with CPU profiles, which use the
same library for symbolization. With cached DWARF information, the
symbolization CPU overhead is negligible.

Example profiles:

*
[pageserver.pb.gz](https://github.com/user-attachments/files/18141395/pageserver.pb.gz)
*
[safekeeper.pb.gz](https://github.com/user-attachments/files/18141396/safekeeper.pb.gz)
This commit is contained in:
Erik Grinaker
2024-12-17 17:51:58 +01:00
committed by GitHub
parent 007b13b79a
commit a55853f67f
6 changed files with 298 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

46
libs/utils/src/http/endpoint.rs
View File

@@ -1,15 +1,22 @@
use crate::auth::{AuthError, Claims, SwappableJwtAuth};
use crate::http::error::{api_error_handler, route_error_handler, ApiError};
use crate::http::request::{get_query_param, parse_query_param};
use crate::pprof;
use ::pprof::protos::Message as _;
use ::pprof::ProfilerGuardBuilder;
use anyhow::{anyhow, Context};
use bytes::{Bytes, BytesMut};
use hyper::header::{HeaderName, AUTHORIZATION, CONTENT_DISPOSITION};
use hyper::http::HeaderValue;
use hyper::Method;
use hyper::{header::CONTENT_TYPE, Body, Request, Response};
use metrics::{register_int_counter, Encoder, IntCounter, TextEncoder};
use once_cell::sync::Lazy;
use regex::Regex;
use routerify::ext::RequestExt;
use routerify::{Middleware, RequestInfo, Router, RouterBuilder};
use tokio::sync::{mpsc, Mutex};
use tokio_stream::wrappers::ReceiverStream;
use tokio_util::io::ReaderStream;
use tracing::{debug, info, info_span, warn, Instrument};
@@ -18,11 +25,6 @@ use std::io::Write as _;
use std::str::FromStr;
use std::time::Duration;
use bytes::{Bytes, BytesMut};
use pprof::protos::Message as _;
use tokio::sync::{mpsc, Mutex};
use tokio_stream::wrappers::ReceiverStream;
static SERVE_METRICS_COUNT: Lazy<IntCounter> = Lazy::new(|| {
register_int_counter!(
"libmetrics_metric_handler_requests_total",
@@ -365,7 +367,7 @@ pub async fn profile_cpu_handler(req: Request<Body>) -> Result<Response<Body>, A
// Take the profile.
let report = tokio::task::spawn_blocking(move || {
let guard = pprof::ProfilerGuardBuilder::default()
let guard = ProfilerGuardBuilder::default()
.frequency(frequency_hz)
.blocklist(&["libc", "libgcc", "pthread", "vdso"])
.build()?;
@@ -457,10 +459,34 @@ pub async fn profile_heap_handler(req: Request<Body>) -> Result<Response<Body>,
}
Format::Pprof => {
let data = tokio::task::spawn_blocking(move || prof_ctl.dump_pprof())
.await
.map_err(|join_err| ApiError::InternalServerError(join_err.into()))?
.map_err(ApiError::InternalServerError)?;
let data = tokio::task::spawn_blocking(move || {
let bytes = prof_ctl.dump_pprof()?;
// Symbolize the profile.
// TODO: consider moving this upstream to jemalloc_pprof and avoiding the
// serialization roundtrip.
static STRIP_FUNCTIONS: Lazy<Vec<(Regex, bool)>> = Lazy::new(|| {
// Functions to strip from profiles. If true, also remove child frames.
vec![
(Regex::new("^__rust").unwrap(), false),
(Regex::new("^_start$").unwrap(), false),
(Regex::new("^irallocx_prof").unwrap(), true),
(Regex::new("^prof_alloc_prep").unwrap(), true),
(Regex::new("^std::rt::lang_start").unwrap(), false),
(Regex::new("^std::sys::backtrace::__rust").unwrap(), false),
]
});
let profile = pprof::decode(&bytes)?;
let profile = pprof::symbolize(profile)?;
let profile = pprof::strip_locations(
profile,
&["libc", "libgcc", "pthread", "vdso"],
&STRIP_FUNCTIONS,
);
pprof::encode(&profile)
})
.await
.map_err(|join_err| ApiError::InternalServerError(join_err.into()))?
.map_err(ApiError::InternalServerError)?;
Response::builder()
.status(200)
.header(CONTENT_TYPE, "application/octet-stream")