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

[Alan Bateman]

On 16/07/2020 01:02, Nikola Grcevski wrote:
> :
>
> Please find the webrev with this improvement here:
>
> http://cr.openjdk.java.net/~adityam/nikola/fast_connect_loopback/
>
Just a few comments on the first iteration.

Can we move the function prototype to the Windows net_util_md.h? That 
would avoid needing to update the shared net_util.h and would avoid 
unused code in the Unix implementation.

Net.connect0 is used for both TCP and UDP sockets. It already uses 
getsockopt to query the socket type so I think we can do that 
unconditionally. That would allow you to use the ioctl when the type == 
SOCK_STREAM and the target is the loopback.

I think we need to find a better name for IN6_IS_ADDR_LOOPBACK_IP4, 
maybe we could find something that has "MAPPED" in the name so that it's 
a bit more consistent with other macros.

-Alan.