[dart-misc] Dart Threading Model

[Jan Mostert]

Hi, I'm busy investigating whether I can use Dart for a backend service on
a new project, but need to understand the threading model to know if it'll
work for me or not.

In Java I can do Runtime.getRuntime().availableProcessors() and then start
threads in proportion to the number of processors available to utilize all
CPUs / Cores on each machine which should give me great throughput on
IO-bounded operations.

What is the Dart Threading model? Does it follow a similar model to Java or
a model similar to NodeJS that has a single thread and an event loop?

[Alexandre Ardhuin]

You can spawn multiple isolates (independent workers that are similar to
threads but don't share memory, communicating only via messages).

See
https://api.dartlang.org/1.13.0/dart-isolate/dart-isolate-library.html
https://api.dartlang.org/1.13.0/dart-io/Platform/numberOfProcessors.html

Alexandre

Post by Jan Mostert
Hi, I'm busy investigating whether I can use Dart for a backend service on
a new project, but need to understand the threading model to know if it'll
work for me or not.
In Java I can do Runtime.getRuntime().availableProcessors() and then
start threads in proportion to the number of processors available to
utilize all CPUs / Cores on each machine which should give me great
throughput on IO-bounded operations.
What is the Dart Threading model? Does it follow a similar model to Java
or a model similar to NodeJS that has a single thread and an event loop?
--
For other discussions, see https://groups.google.com/a/dartlang.org/
For HOWTO questions, visit http://stackoverflow.com/tags/dart
To file a bug report or feature request, go to http://www.dartbug.com/new
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[Jan Mostert]

Thanks Alexandre!
I've read through the docs + some examples and it seems Isolates will cater
for the majority of my multithreading needs.

How would one implement something like an AtomicLong or AtomicHashMap that
allows concurrent read / writes in a synchronized fashion?
One could always keep that data in an ACID compliant DB, but that's a lot
of overhead.

Post by Alexandre Ardhuin
You can spawn multiple isolates (independent workers that are similar to
threads but don't share memory, communicating only via messages).
See
https://api.dartlang.org/1.13.0/dart-isolate/dart-isolate-library.html
https://api.dartlang.org/1.13.0/dart-io/Platform/numberOfProcessors.html
Alexandre

Post by Jan Mostert
Hi, I'm busy investigating whether I can use Dart for a backend service
on a new project, but need to understand the threading model to know if
it'll work for me or not.
In Java I can do Runtime.getRuntime().availableProcessors() and then
start threads in proportion to the number of processors available to
utilize all CPUs / Cores on each machine which should give me great
throughput on IO-bounded operations.
What is the Dart Threading model? Does it follow a similar model to Java
or a model similar to NodeJS that has a single thread and an event loop?
--
For other discussions, see https://groups.google.com/a/dartlang.org/
For HOWTO questions, visit http://stackoverflow.com/tags/dart
To file a bug report or feature request, go to http://www.dartbug.com/new
---
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--
For other discussions, see https://groups.google.com/a/dartlang.org/
For HOWTO questions, visit http://stackoverflow.com/tags/dart
To file a bug report or feature request, go to http://www.dartbug.com/new
---
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[Anders Holmgren]

You don't need any synchronisation primitives. Isolates is more like an
Actor model. You pass messages between isolates.

Dart doesn't support multiple threads sharing memory so it doesn't have any
of those sorts of synchronisation primitives

Post by Jan Mostert
Thanks Alexandre!
I've read through the docs + some examples and it seems Isolates will
cater for the majority of my multithreading needs.
How would one implement something like an AtomicLong or AtomicHashMap that
allows concurrent read / writes in a synchronized fashion?
One could always keep that data in an ACID compliant DB, but that's a lot
of overhead.

Post by Alexandre Ardhuin
You can spawn multiple isolates (independent workers that are similar to
threads but don't share memory, communicating only via messages).
See
https://api.dartlang.org/1.13.0/dart-isolate/dart-isolate-library.html
https://api.dartlang.org/1.13.0/dart-io/Platform/numberOfProcessors.html
Alexandre

Post by Jan Mostert
Hi, I'm busy investigating whether I can use Dart for a backend service
on a new project, but need to understand the threading model to know if
it'll work for me or not.
In Java I can do Runtime.getRuntime().availableProcessors() and then
start threads in proportion to the number of processors available to
utilize all CPUs / Cores on each machine which should give me great
throughput on IO-bounded operations.
What is the Dart Threading model? Does it follow a similar model to Java
or a model similar to NodeJS that has a single thread and an event loop?
--
For other discussions, see https://groups.google.com/a/dartlang.org/
For HOWTO questions, visit http://stackoverflow.com/tags/dart
To file a bug report or feature request, go to
http://www.dartbug.com/new
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--
For other discussions, see https://groups.google.com/a/dartlang.org/
For HOWTO questions, visit http://stackoverflow.com/tags/dart
To file a bug report or feature request, go to http://www.dartbug.com/new
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[Jan Mostert]

"You don't need any synchronisation primitives"

I probably don't, will do some prototyping to see if Dart Isolates are
performant enough for my needs.
Thanks for the replies!

Interesting article comparing Akka to NodeJS to Java with Threads and
Futures and Dart and Go:
http://java-is-the-new-c.blogspot.co.za/2014/06/java-concurrency-learning-from-nodejs.html

Post by Anders Holmgren
You don't need any synchronisation primitives. Isolates is more like an
Actor model. You pass messages between isolates.
Dart doesn't support multiple threads sharing memory so it doesn't have
any of those sorts of synchronisation primitives

Post by Jan Mostert
Thanks Alexandre!
I've read through the docs + some examples and it seems Isolates will
cater for the majority of my multithreading needs.
How would one implement something like an AtomicLong or AtomicHashMap
that allows concurrent read / writes in a synchronized fashion?
One could always keep that data in an ACID compliant DB, but that's a lot
of overhead.

You can spawn multiple isolates (independent workers that are similar to

Post by Jan Mostert

Post by Alexandre Ardhuin
threads but don't share memory, communicating only via messages).
See
https://api.dartlang.org/1.13.0/dart-isolate/dart-isolate-library.html
https://api.dartlang.org/1.13.0/dart-io/Platform/numberOfProcessors.html
Alexandre

Post by Jan Mostert
Hi, I'm busy investigating whether I can use Dart for a backend service
on a new project, but need to understand the threading model to know if
it'll work for me or not.
In Java I can do Runtime.getRuntime().availableProcessors() and then
start threads in proportion to the number of processors available to
utilize all CPUs / Cores on each machine which should give me great
throughput on IO-bounded operations.
What is the Dart Threading model? Does it follow a similar model to
Java or a model similar to NodeJS that has a single thread and an event
loop?
--
For other discussions, see https://groups.google.com/a/dartlang.org/
For HOWTO questions, visit http://stackoverflow.com/tags/dart
To file a bug report or feature request, go to
http://www.dartbug.com/new
---
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Groups "Dart Misc" group.

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--
For other discussions, see https://groups.google.com/a/dartlang.org/
For HOWTO questions, visit http://stackoverflow.com/tags/dart
To file a bug report or feature request, go to
http://www.dartbug.com/new
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--

For other discussions, see https://groups.google.com/a/dartlang.org/
For HOWTO questions, visit http://stackoverflow.com/tags/dart
To file a bug report or feature request, go to http://www.dartbug.com/new
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