Message passing between threads: Java 4 times faster than D

Andrei Alexandrescu SeeWebsiteForEmail at
Thu Feb 9 11:35:00 PST 2012

On 2/9/12 10:31 AM, Marco Leise wrote:
> Am 09.02.2012, 18:35 Uhr, schrieb Andrei Alexandrescu
> <SeeWebsiteForEmail at>:
>> On 2/9/12 6:10 AM, Gor Gyolchanyan wrote:
>>> Generally, D's message passing is implemented in quite easy-to-use
>>> way, but far from being fast.
>>> I dislike the Variant structure, because it adds a huge overhead. I'd
>>> rather have a templated message passing system with type-safe message
>>> queue, so no Variant is necessary.
>>> In specific cases Messages can be polymorphic objects. This will be
>>> way faster, then Variant.
>> cc Sean Kelly
>> I haven't looked at the implementation, but one possible liability is
>> that large messages don't fit in a Variant and must use dynamic
>> allocation under the wraps. There are a number of ways to avoid that,
>> such as parallel arrays (one array per type for data and one for the
>> additional tags).
>> We must make the message passing subsystem to not use any memory
>> allocation in the quiescent state. If we're doing one allocation per
>> message passed, that might explain the 4x performance difference (I
>> have no trouble figuring Java's allocator is this much faster than D's).
>> Andrei
> Well, what does +1 Variant and +1 LinkedListNode sum up to?

Sorry, I don't understand...


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