Hi Igor,
I've implemented an Actor-type system (and as it stands, Akka IO) as a PoC
using the Disruptor myself and was waiting for the day a good
implementation becomes available for Akka!
My experience is -- and everything that the LMAX developers say -- backs up
the claim that the best performance from the RingBuffer comes when batching
operations, as this decreases the frequency of memory fencing instructions
executed. Essentially, use the RingBuffer for inter-core communication
only.
So far I've only had a quick glance at your code and don't have really any
knowledge of the internals of Akka's message passing. Do you see any
opportunity within your implementation to batch writes and reads?
On Monday, 6 January 2014 21:34:55 UTC+11, Igor Konev wrote:
>
> Hi Roland,
>
> Although you mentioned above that hasMessages is called upon every tell
> operation, it looks like it is not the case. Not taking BalancingDispatcher
> into account hasMessages is called from Mailbox's
> canBeScheduledForExecution as follows
>
> final def canBeScheduledForExecution(hasMessageHint: Boolean,
> hasSystemMessageHint: Boolean): Boolean = status match {
> case Open | Scheduled ⇒ hasMessageHint || hasSystemMessageHint ||
> hasSystemMessages || hasMessages
> case Closed ⇒ false
> case _ ⇒ hasSystemMessageHint || hasSystemMessages
> }
>
> But hasMessages and hasSystemMessageHint are never false at the same time
> when canBeScheduledForExecution is called (indirectly) from Dispatcher:
>
> protected[akka] override def registerForExecution(mbox: Mailbox,
> hasMessageHint: Boolean, hasSystemMessageHint: Boolean): Boolean = {
> if (mbox.canBeScheduledForExecution(hasMessageHint,
> hasSystemMessageHint)) { //This needs to be here to ensure thread safety
> and no races
> ...
>
> protected[akka] def dispatch(receiver: ActorCell, invocation: Envelope):
> Unit = {
> val mbox = receiver.mailbox
> mbox.enqueue(receiver.self, invocation)
> registerForExecution(mbox, true, false)
> }
>
> protected[akka] def systemDispatch(receiver: ActorCell, invocation:
> SystemMessage): Unit = {
> val mbox = receiver.mailbox
> mbox.systemEnqueue(receiver.self, invocation)
> registerForExecution(mbox, false, true)
> }
>
> So hasMessages is never called upon tell.
>
> пятница, 3 января 2014 г., 10:51:33 UTC+2 пользователь rkuhn написал:
>>
>> Hi Igor,
>>
>> thanks for sharing! On first (cursory) sight it looks like your mailbox
>> might cause missed wake-ups because head and tail are read by the
>> enqueueing thread without synchronization (i.e. disruptor cursor is moved
>> but updates to head and tail have not been published; this might be
>> mitigated by clever ordering of effects, but my spidey senses make me
>> uneasy on this one).
>>
>> Regards,
>>
>> Roland
>>
>> 1 jan 2014 kl. 20:04 skrev Igor Konev <[email protected]>:
>>
>> > If somebody is still interested, I've implemented a bounded mailbox
>> using Disruptor and obtained a throughput gain of about 50% over the
>> standard bounded mailbox. You can find the source code here
>> https://github.com/yngui/akka-disruptor.
>> >
>> > --
>> >>>>>>>>>>> Read the docs: http://akka.io/docs/
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>>
>>
>> Dr. Roland Kuhn
>> Akka Tech Lead
>> Typesafe – Reactive apps on the JVM.
>> twitter: @rolandkuhn
>>
>>
>>
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