RFR(s): Improving performance of Windows socket connect on the loopback adapter

[Alan Bateman]

On 16/07/2020 05:37, Bernd Eckenfels wrote:
> Hello Nikola,
>
> Can you explain why timeouts play a role here at all? Normally when 
> connecting to a non existing socket it should immediately respond with 
> a TCP RST and that should not cause a retry or delay.
>
Nikola mentioned that he is in contact with someone working on Windows 
networking and it would be useful to know why this isn't changed in 
Windows and it would avoid a workaround in the JDK or anywhere else that 
attempt to establish a connection to the loopback. We initially started 
to see issues on Windows 10, Michael has more on this in JDK-8234823 [1].

I should say that I have no objection to Nikola's proposal, I think it's 
great to know that there is an ioctl to change this. I suspect we might 
have to do the equivalent in the JDWP socket transport although probably 
low priority as the shared memory transport is the default there.

-Alan

[1] https://bugs.openjdk.java.net/browse/JDK-8234823
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