Rheaper is a in-process heap profiler for rust, that plugs in place and collect allocation data, and later stores it in a SQLite database for analysis. It supports runtime activation/deactivation.

To enable heaptrack in you project, set the global allocator:

#[global_allocator]
static GLOBAL: Rheaper::Allocator<mimalloc::MiMalloc> =
    rheaper::Allocator::from_allocator(mimalloc::MiMalloc);

at any point, tracking can be enabled:

let profile_path = rheaper::enable_tracking(Rheaper::TrackerConfig {
    /// how deep should the call stack be sampled
    max_stack_depth: 30,
    /// each thread that allocates acquire a local tracker from the global pool. That's how many trackers can be created
    max_trackers: 200,
    /// How many alloc events are buffered per local tracker
    tracker_event_buffer_size: 5_000,
    /// How often to sample backtraces, 1.0 is always, 0.0 is never.
    sample_rate: 1.0,
    /// where th profile will be written
    profile_dir: PathBuf::new(),
});

Recording is stopped with:

rheaper::disable_tracking();

This will resolve pending backtraces, and flush profiling data to disk. After than, the profile can be analyzed

rheaper rip-4744532 profile.db

this will create a profile.db sqlite database. This database can be opened with sqlite to perform analytics.

Examples

show the 10 biggest contributor by callsites:

SELECT bt, sum(size) FROM allocations GROUP BY bt ORDER BY sum(size) DESC LIMIT 10;

bt                    sum(size)
--------------------  ---------
14887427388493581654  61044456
6831336122721510729   52678176
2113490791341760087   52678176
15757739337697011469  31692912
3437328128932597320   24435936
15830995416840919940  10029120
7763277092675977093   9981504
10258202288105587101  9981504
12697966346495929209  3928320
4493127380101385995   3883680

show allocations, by callsites, that lives for more than 10 seconds:

SELECT bt, count(0), sum(size) FROM allocations where dealloc_after NOT NULL AND dealloc_after - alloc_after < 10000 GROUP BY bt ORDER BY sum(size) DESC LIMIT 5;

bt                    count(0)  sum(size)
--------------------  --------  ---------
14887427388493581654  372       61044456
6831336122721510729   372       52678176
2113490791341760087   372       52678176
15757739337697011469  372       31692912
3437328128932597320   372       24435936

bt can be used to query the backtraces table:

select frame_no, sym from backtraces where id = '14887427388493581654' limit 10;                

frame_no  sym
--------  ------------------------------------------------------------
0         backtrace::backtrace::libunwind::trace::h313fcf731c1ed43a

1         <rheaper::alloc::Allocator<A> as core::alloc::global::Glob
          alAlloc>::alloc::{{closure}}::hd945306712c35cdc

2         rheaper::alloc::with_local::{{closure}}::{{closure}}::{{cl
          osure}}::{{closure}}::h984dd2b94bca5c66

3         rheaper::alloc::TrackerGuard::with::h2f7bcd4120d6efa7

4         rheaper::alloc::with_local::{{closure}}::{{closure}}::{{cl
          osure}}::h51d6f70563022314

5         std::thread::local::LocalKey<T>::try_with::hff003d76feecb4a9

6         rheaper::alloc::with_local::{{closure}}::{{closure}}::h233
          b8e1d7f3eb3c5

7         rheaper::alloc::untracked::{{closure}}::hc0fb5ce1fd3deaf9

8         std::thread::local::LocalKey<T>::try_with::h8850e1a558f39df6

9         std::thread::local::LocalKey<T>::with::hcab5ce8347c6de7c

Credits

thanks you @gmourier for the logo!