Austin: Diagnostics

[joshgav]

Transferring from nodejs/diagnostics#58

Some topics from that thread:

• tracing: controller, protocol, format
• async_hooks
• es6 module patching
• inspector protocol and tools

/cc @nodejs/diagnostics @watson

[danielkhan]

Adding

• Event Loop metrics (pending tasks, tasks per second). More or less like Linux load.

[joshgav]

From the November Diag WG meeting -

• work on adding trace points to Node and core modules based on Trace event support for Node.js nodejs/node#9304
• discuss context propagation across async boundaries (@ofrobots - I think that's what you meant)

[joshgav]

Several of us chatted yesterday and agreed to meet Friday for Diagnostics, allowing Thursday afternoon for participating with other groups etc. Any opposed please let us know here.

Let's flesh out the agenda a bit, the following is based on what's above and other evolving discussions:

• TracingController

  • Adding trace points to core modules
  • JS API?
  • Intended use cases

• Inspector - CLI Debugger

  • node-inspect in core itself or alongside it?
  • Opportunities for new capabilities available through inspector - specifically CPU and Heap profiling at the moment.

We may also want to discuss the UUID associated by Inspector with each process as in nodejs/node#9185.

• Context propagation and async_hooks (@ofrobots)
• Event loop (@danielkhan)

/cc @nodejs/ctc in case some of you can join.

[Trott]

I'd like to be there for the Debugger stuff.

[Trott]

(Time?)

[jkrems]

I'd also like to join for the Debugger stuff.

[joshgav]

@Trott

Time?

Going with #35, how about 9am? Meet near where the keynotes were and choose a room. We can review and set the agenda first thing. Perhaps we can spend a chunk of the time coding and presenting to each other.

@jkrems - Was counting on you coming! Thanks!

[danielkhan]

I'll be there at 9am.

[jkrems]

@joshgav Side note - inspired by your talk today I added some quick profiler support to node-inspect:

debug> profile
# [...]
debug> profileEnd
[Profile 2572307μs]
debug> _.save('my.cpuprofile')
Saved profile to /path/to/cwd/my.cpuprofile
debug> takeHeapSnapshot('my.heapsnapshot')
Heap snaphost prepared.
Wrote snapshot: /path/to/cwd/my.heapsnapshot

[joshgav]

Notes: https://docs.google.com/document/d/1hUiG1nv4hxjnznN2NjU3F-MzXtKhWxvMI3R8caJyzCs/edit

[joshgav]

Great meeting everyone! Cooked notes in this PR: nodejs/diagnostics#76, PTAL.