pflames v1.1.0

pflames

pflames is a tool for generating flamegraphs from various profile formats.

The following formats are supported (detected by file extension):

• *.cpuprofile, as generated by older Chrome DevTools, v8-profiler, cli-profile, etc.
• perf.data, as generated by perf record on Linux.
• isolate*.log, as generated by node --prof.

The data is processed from these formats into flamegraphs generated by Brendan Gregg's FlameGraph tool, saved to a local file based on the input filename, then immediately opened in your web browser.

Usage

Examples:

$ npm i -g cli-profile
$ cli-profile myscript.js
$ ls *.cpuprofile
profile1522910623600.cpuprofile
$ pflames profile1522910623600.cpuprofile

$ # Note: Ensure your script has `process.on('SIGINT', process.exit)`
$ node --prof myscript.js
$ ls *.log
isolate-0x2259700-v8.log
$ pflames isolate-0x2259700-v8.log

$ sudo perf record -i -g -F 99 -- node --perf-basic-prof myscript.js
$ pflames perf.data

You can also compare two profiles of the same format by passing them both in. A difference flamegraph will be generated:

$ pflames thing1.cpuprofile thing2.cpuprofile

You can also use the same data to generate an icicle graph, so you can get a better view of what's calling a heavy function:

$ pflames --icicle thing1.cpuprofile

Easily create perf.data files (Linux only)

You can use the run and attach commands to profile Node.js and other Linux processes. This will run perf record behind the scenese to generate a perf.data.

• run spawns a process with the given command with perf record, profiling it for its entire lifetime. If the process binary being run is node, it will add --perf-basic-prof to the options. Examples:

# profile a Node.js app
$ pflames run node myapp.js
# profile a Rust app (you should use release builds for this)
$ pflames run target/release/myapp

• attach starts profiling a given PID until the that process exits, a SIGINT (Ctrl+C) is received, or a given number of seconds has elapsed.

# Assume PID 1234 is running and we want to profile it:
$ pflames attach 1234
# Now either Ctrl+C to finish profiling or wait for 1234 to finish
# Or profile it for exactly 5 seconds:
$ pflames attach 1234 5

Both of these commands produce perf.data files which can be then processed with plfames:

$ pflames perf.data

License

MIT License. See LICENSE.txt