pew

README

pew

Pew records the memory usage of an arbitrary process.

Usage

Use pew run <command> to run command and record its memory usage. Pew will keep running until the process exits or it receives a SIGINT signal (Ctrl-C).

Pew will write the memory profile of your process to a timestamped CSV file inside the .pew. subdirectory of the current working directory from where it's launched.

README-driven development

The following features have not yet been implemented, but pew is developed using a README-driven development approach. The following section is not representative of the current development state, but it's the roadmap that all development will take place against.

Multiple git revisions

If it's run from within a git repository, pew picks up the SHA of the current revision and adds it to the memory profile metadata, so it can be more easily identified and multiple revisions can be compared against each other.

This is because, while benchmarking or tracking down memory leaks, it is often useful to make one small change at a time, and create a separate git commit for every change, so the history of one's debugging attempts can be played back later.

This behaviour can be disabled by using the --no-git command-line flag.

Attach to an existing process

Use the attach command to attach pew to an existing process by passing in the latter's PID.

$ pew attach 1360

Pew will monitor the process and quit when it senses that the process has terminated. Using Ctrl-C on pew to stop the data collection early will have no effect on the process it's monitoring.

Web server

Use the server command to start a local HTTP server that exposes a minimal, real-time web interface to the data that another instance of pew is collecting.

$ pew server
[pew] HTTP server is listening on 0.0.0.0:7777

Open the address from the command-line output in a web browser to see a list of the individual samples being collected. Selecting a sample that's currently in progress will display graphs that are updated in real time, as new data is collected.

License

MIT