Avoiding Async array copies #2839
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bbakerman
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May 30, 2022
bbakerman
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May 30, 2022
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Overall I approve of this approach. We can know up front how many CFs we have and hence this will stop a list allocation which gets turned into an array allocation. We can go straight to an array allocation of the right size.
It would be interesting to see if ImmutableList.Builder on the returned results ended up faster of slow - it depends on the lifetime of the objects involved of course and how often they get copied into some other list
| overallResult.completeExceptionally(exception); | ||
| return; | ||
| } | ||
| List<T> results = Collections.singletonList(completableFuture.join()); |
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Use ImmutabeList.of() -we prefer the guava lists where possible
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A typed interface to build CompletableFuture.allOf without intermediate List allocations.
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@bbakerman please have another look, I should have covered all your inputs... |
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@bbakerman @andimarek hi guys :)
while profiling in YourKit, I spotted some extra array allocations for CompletableFuture. This is still an idea... and a work in progress... please have a look :-) There is a special handling for SelectionSet of only 1 field: in this case the array allocation could be removed completely.
Baseline:
After this PR:
is about 5-6% better on my machine (that is quite old, so maybe it is less on newer machines). Do you see other hot spots where this could beneficial?