Do not allocate capacity in ready_chunks #2657
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Hmm... Depending on the size of the item, reallocation may occur with each push, but 1024 bytes on the stack is relatively large, so it probably seems fine? |
Snippet you pointed at is min non-zero capacity. The following line is: where old Or I didn't understand your comment. |
`read_chunks` practically often returns items when not all capacity filled. So always allocating full capacity results in excessive allocation. This is especially an issue when `capacity` parameter passed is large (to be able to handle streams efficiently under high load).
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Reserving `ready_chunks` limit every time may be too expensive when the limit is high but only a few number of messages available. Now rely on `Stream::size_hint` to reserve the capacity. If underlying stream implements `size_hint`, this will work great. Otherwise `ready_chunk` will be somewhat less efficient. This is better alternative to rust-lang#2657
stepancheg
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Oct 30, 2022
Reserving `ready_chunks` limit every time may be too expensive when the limit is high but only a few number of messages available. Now rely on `Stream::size_hint` to reserve the capacity. If underlying stream implements `size_hint`, this will work great. Otherwise `ready_chunk` will be somewhat less efficient. This is better alternative to rust-lang#2657
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Closing in favor of #2661. |
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read_chunkspractically often returns items when not all capacity filled. So always allocating full capacity results in excessive allocation.This is especially an issue when
capacityparameter passed is large (to be able to handle streams efficiently under high load).