f8e58737eb
I do some benchmarking with our benchmarker tool which uses "perf stat" under the hood. "perf stat" uses hardware counters, but we have a limited amount of those. The benchmarker tool asks for 3 event types that will use 3 hardware counters. If there aren't 3 available it will do "scaling" and only measure what it's asked some percentage of the time so it can still measure all of the stuff it's asked. This should be fine. My computer has 4 hardware counters. I think. Only today I still experienced scaling. And previously I asked for 4 event types because I had 4 hardware counters, but then suddenly 1 went missing. As it turns out another process was using hardware counters. This CL includes a tool that - at least seeems to - be able to find other processes using perf events (although it might not be events that use hardware counters), thus possibly allowing you to kill that or those process(es). I did, and I now have 4 hardware counters again. I also made scaling more visible if it happens when using the benchmark tool. Before it was hidden between other output, not it's also printed at the end, together with a hint to use the new tool to attempt to fix it. Change-Id: Ia51db04a4f25d1d82c3d32b3901cded7d980e7f5 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/352525 Commit-Queue: Jens Johansen <jensj@google.com> Reviewed-by: Chloe Stefantsova <cstefantsova@google.com> |
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Dart
An approachable, portable, and productive language for high-quality apps on any platform
Dart is:
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Approachable: Develop with a strongly typed programming language that is consistent, concise, and offers modern language features like null safety and patterns.
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Portable: Compile to ARM, x64, or RISC-V machine code for mobile, desktop, and backend. Compile to JavaScript or WebAssembly for the web.
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Productive: Make changes iteratively: use hot reload to see the result instantly in your running app. Diagnose app issues using DevTools.
Dart's flexible compiler technology lets you run Dart code in different ways, depending on your target platform and goals:
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Dart Native: For programs targeting devices (mobile, desktop, server, and more), Dart Native includes both a Dart VM with JIT (just-in-time) compilation and an AOT (ahead-of-time) compiler for producing machine code.
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Dart Web: For programs targeting the web, Dart Web includes both a development time compiler (dartdevc) and a production time compiler (dart2js).
License & patents
Dart is free and open source.
See LICENSE and PATENT_GRANT.
Using Dart
Visit dart.dev to learn more about the language, tools, and to find codelabs.
Browse pub.dev for more packages and libraries contributed by the community and the Dart team.
Our API reference documentation is published at api.dart.dev, based on the stable release. (We also publish docs from our beta and dev channels, as well as from the primary development branch).
Building Dart
If you want to build Dart yourself, here is a guide to getting the source, preparing your machine to build the SDK, and building.
There are more documents on our wiki.
Contributing to Dart
The easiest way to contribute to Dart is to file issues.
You can also contribute patches, as described in Contributing.