RFR: 8316156: (ch) Channels.newOutputStream(ch).write(bigByteArray) allocates a lot of direct memory [v4]

[Bernd]

On Fri, 15 Sep 2023 00:17:45 GMT, David Schlosnagle <duke at openjdk.org> wrote:

>> A quick measurement suggests that doubling the buffer size to 16384 would increase `read` throughput by more than 15%, and `write` throughput by more than 40%.
>
> That would be a nice additional benefit on top of reducing the direct memory allocations

I guess it’s still slower than uncapped. Brian mentioned only 8k vs 16k, not bigger or unconstrained. (And it also depends on the physical drivers below the test system)

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PR Review Comment: https://git.openjdk.org/jdk/pull/15733#discussion_r1327137145