[GitHub] activemq-artemis issue #2484: ARTEMIS-2216 Use a specific executor for pageS...

[qihongxu]

Github user qihongxu commented on the issue:

    https://github.com/apache/activemq-artemis/pull/2484
  
    > @qihongxu,
    > 
    > re:
    > "
    > According to this we have an internal branch that removes isPaging() 
method’s readlock in PagingStoreImpl, along with adding pageSyncTimer’s 
specific executor. After that we performed a same test and get a result of 
21k/25k Send&Receive–in total 46k TPS. This version runs smoothly in our use 
case but we are still exploring potential effects.
    > "
    > 
    > Agree that as the QueueImpl:checkDepage which is called from deliver 
method, only schedules another depage asynchronously that the read barrier lock 
for that is over kill as it doesn't have to be strongly consistent correct.
    > 
    > I think changing the current method could be dangerous, unless we do a 
fuller analysis on all its uses, but i think we could easily add a new method 
named something like "isPagingDirtyRead" which can return without the readlock, 
it will mean the returned value isn't always 100% accurate but in cases such as 
checkDepage, we don't need it to be, its just a single, and we can call it 
where we know its safe to.
    > 
    > Would you be happy adding this, (will need to be exposed via 
PageSubscription)? And updating checkDepage to use that one?
    
    
    As you suggested we tried update checkDepage with a new "isPagingDirtyRead" 
method which can return without the readlock. But after running same tests on 
this version it seems that checkDepage did not affect receive performance too 
much. Instead, CursorIterator#hasNext in PageSubscriptionImpl also called 
isPaging() and had a significant impact on receive performance. According to 
this we updated hasNext() and forced it to use the new “isPagingDirtyRead”. 
Below is the result chart.
    (P.S the original ver is a control group, not exactly the “original” 
master-branch build. It has been applied with specific pageSyncTimer executor, 
and cache durable in PageReference - See PR Artemis-2214.)
    
    
      | Send&Receive | In Total
    -- | -- | --
    Ver Original | 30k/12.5k | 32.5k
    Ver Modified checkDepage | 31.1k/11.3k | 42.4k
    Ver Modified hasNext | 23.8k/23.5k | 47.3k
    
    Detailed TPS chart can be seen in attachment. (Sorry we dont have enough 
time for running tests. Just got back to work today)
    [TPS 
chart.docx](https://github.com/apache/activemq-artemis/files/2723731/TPS.chart.docx)



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