Dart Analyzer performance is crippling my laptop

[eseidel]

PID    COMMAND      %CPU TIME     #TH   #WQ  #PORT MEM    PURG   CMPRS  PGRP  PPID  STATE    BOOSTS         %CPU_ME %CPU_OTHRS UID  FAULTS     COW     MSGSENT   MSGRECV
9888   dart         54.6  15:18.07 7/2   0    67    202M+  0B     3296M- 9335  9825  running  *0[1]            0.00000 0.00000    501  61750923+  360     520

That Dart process is the flutter deamon process.

It's also for some reason causing kernel_task to be above 150% of CPU usage (using more than one core) and then the rest of my machine is consumed by the dart process itself. I'm not sure what triggers so much kernel_task activity? Maybe due to using more RAM than the machine has?

This is a somewhat old laptop ('11 MacBook Air, 4GB RAM, 1.8ghz dual core). But I basically can't do anything else on the machine if I have Atom open and the analyzer server is running.

I don't think this is something we necessarily need to address for 1.0 (and I know lots of perf work is already going into the analyzer), but it's something to be aware of.

What makes this worse is that I have no option to tell the analyzer to calm down or to pause, I know that if I quit Atom I'm just causing it to run again from scratch, etc.

@pq @kevmoo

[eseidel]

The project I have open in atom is (the root of) https://github.com/eseidel/saycbridge which is an old personal project of mine which happens to have some flutter code in it.

[eseidel]

It's likely that at least some of this will go away with analyzer summaries, since then the analyzer shouldn't have to analyze the flutter source tree in this case (it's in third_party/flutter as a pinned git submodule).

[eseidel]

The big problem appears to be the memory usage.

dart    2.42 GB 2.18 GB 9   70  12234   eseidel 74.0    4:56.01 676     -   No  No  0 bytes 0 bytes 0   0   0 bytes 0 bytes 64 bit  0 bytes 0 bytes 0 bytes No  No      0 bytes No  

I'm not sure how tiny 4GB of system memory is by modern standards. But my 2011 personal laptop just can't handle a 2GB+ analyzer process. :/

[abarth]

I saw something similar recently on my machine. I think the analyzer server has some sort of leak. Next time it happens, I want to try connecting with observatory and taking a heap profile.

/cc @pq

[eseidel]

If someone can post instructions on how to find the observatory port for this process (maybe netstat?) I'm happy to connect and post what I see. I have two copies of flutter. One at /src/flutter which atom sees, and a second in my project under /src/saycbridge/third_party/flutter I'm opening /src/sacybridge in atom.

[✓] Flutter (on Mac OS, channel alpha)
    • Flutter at /Stuff/Projects/flutter
    • Framework revision 646b5350d1 (9 days ago), engine revision 7fab0c350b

[✓] Android toolchain - develop for Android devices (Android SDK 22.0.1)
    • Android SDK at /Users/eseidel/Library/Android/sdk/
    • Platform android-22, build-tools 22.0.1
    • Java(TM) SE Runtime Environment (build 1.8.0_25-b17)

[✓] iOS toolchain - develop for iOS devices (Xcode 7.1)
    • XCode at /Applications/Xcode.app/Contents/Developer
    • Xcode 7.1, Build version 7B91b
    x ideviceinstaller not available; this is used to discover connected iOS devices.
      Install via 'brew install ideviceinstaller'.
    x ios-deploy not available; this is used to deploy to connected iOS devices.
      Install via 'brew install ios-deploy'.

[✓] Atom - a lightweight development environment for Flutter
    • Atom installed; Flutter plugin version 0.2.2

[devoncarew]

I'll dig up the flags to enable the obs. port.

/cc @bwilkerson

[devoncarew]

If you open atom's config file directly (Atom > Config), in the dartlang section you can add a new key, debugAnalysisServer: true. When you restart atom, the analysis server's diagnostics page will be available at localhost:23072. That will have some indication of where the time and memory is going.

[devoncarew]

@eseidel, I want to confirm that the expensive process is running the analysis server, and not the flutter deamon process. They're both active when atom is open; flutter daemon should be doing very very little.

[eseidel]

The runaway process is /src/flutter/bin/cache/dart-sdk/bin/dart /src/flutter/bin/cache/dart-sdk/bin/snapshots/analysis_server.dart.snapshot

[sethladd]

I've seen this a few times. I wonder if our analytics should keep an eye on the health of the daemon and analysis server, in order to see if something systemic is going on?

[devoncarew]

I'd lean towards getting the resource consumption of the analysis server under continuous test and measurement. Knowing the numbers better will set us up well for driving them down, and make us better aware of regressions. Will meet with @bwilkerson next week to put some goals in place.

[devoncarew]

There's a new version of the plugin with a preferences setting to enable the analysis server's diagnostics. Setting it now also starts the analysis server with an observatory port open, and display the port that the obs. bound to in a toast.

[eseidel]

Here is copy/paste out of the heap profiler from the analyzer on my machine:
https://gist.github.com/eseidel/6e8767adc70b8a0cdcba84ecbcac167c

[pq]

cc @bwilkerson @scheglov