Rust-Async-Context-Tracer

• Understand the behavior of your asynchronous tasks and futures.
  ▶️New branch for tokio-runtime is working in progress

Prerequisite:

• Please install and build uftrace first
• Build your executable in debug mode

What is a tracing tool for asynchronous rust?

• With this tool, we can:
  • Understand the behavior of rust asynchronous tasks, including the polling time of the futures and the waiting time of the futures
  • Find out some abnormal execution patterns (long polling time may cause blocking)
• e.g. Here is a simple rust asynchronous program:

use async_std::task;
use std::time::Duration;

async fn my_test()
{
   task::sleep(Duration::from_millis(100)).await;
}
#[async_std::main]
async fn main(){
     my_test().await;
     task::sleep(Duration::from_millis(150)).await;
}

And We can have a visualization for our rust asynchronous program:

Usage

• Clone the repository (No building needed)
• Move the profile directory into your target directory

profile
├── parser_nu.py
├── parser.py
└── profile.sh

• Run the profiler script:
  For tracing all futures:
  . profile.sh $EXECUTABLE_NAME $OUTPUT_FILE_NAME
  Tracing the compiler generated futures only:
  . profile.sh $EXECUTABLE_NAME $OUTPUT_FILE_NAME --generated-future
  ⚠️ The function location of futures are not provided by default, you can pass argument --get-location to get locations. Note that if enable it, the progress will become very slow, see issue #2.
• After executing the script, we get a json file in the profile directory

profile
├── parser_nu.py
├── parser.py
├── profile.sh
└── $OUTPUT_FILE_NAME.json

• Then we can use the trace-viewer to visualize the result:
  • Open the chrome browser
  • Type chrome://tracing/ on your chrome browser
  • Load the json file generated by profiler
• Result example:
  

TODO:

• Different task(future) instances should be recognized
• Combinators(e.g. join!, select!) issues
• Speed up for parsing and recording are neeeded
• Annotate different tasks with different colors
• Tracing progress should be done correctly in release mode
• Some locations information are wrong because of the same demangled symbol

Acknowledgement:

This work was sponsored by the internship of ADLINK during 2021-2022.

License:

• MIT license (http://opensource.org/licenses/MIT)