Backporting the TCP loopback fast path (Windows) improvement to OpenJDK v7

[Seán Coffey]

Valeriy,

I used the jdk7u patch that was attached to the mail request. It applied 
cleanly. I've posted webrev here for reference (patch there also):
http://cr.openjdk.java.net/~coffeys/webrev.8060170.7u/webrev/

The new WSAIoctl call would appear to be failing with WSAEINVAL. The 
NET_EnableFastTcpLoopback call already tests for WSAEOPNOTSUPP - maybe 
we should test for WSAEINVAL also and perhaps return silently if windows 
don't support the option. Or maybe - we state this as desired behaviour 
- i.e this option is suitable for modern windows kernels - your note 
below would contradict what I'm seeing though.

The test passes for me on Windows 7 and fails on Windows XP.

regards,
Sean.

On 15/01/2015 11:15, Valery Kopylov (Akvelon) wrote:
> Hi Sean,
>
> Our TCP loopback implementation should process the option correctly on older windows kernels. I tried to reproduce the issue, but it works fine on my side. So I have an assumption that part of the code present on jdk9 patch has been lost and this causes such errors.
> Did you use the patch for jdk7 sent by Martin or perform the backporting from jdk8 or 9 by yourself?
> Could you please send me output of "hg diff" command in jdk folder?
>
>
> Best regards,
> Valeriy Kopylov
>
> -----Original Message-----
> From: Seán Coffey [mailto:sean.coffey at oracle.com]
> Sent: Tuesday, January 13, 2015 22:31
> To: Martin Sawicki (MS OPEN TECH); jdk7u-dev at openjdk.java.net
> Cc: Valery Kopylov (Akvelon); Kirk Shoop (MS OPEN TECH); Alan Bateman
> Subject: Re: Backporting the TCP loopback fast path (Windows) improvement to OpenJDK v7
>
> Hi Martin,
>
> I've run into a problem in backporting this to JDK 7u. The test fails on our build/test systems. (windows XP) -
>> reason: User specified action: run main/othervm
>> -Djdk.net.useFastTcpLoopback StressLoopback elapsed time (seconds):
>> 0.64
>> STDOUT:
>> STDERR:
>> java.net.SocketException: Invalid argument: fastLoopback
>> 	at sun.nio.ch.Net.socket0(Native Method)
>> 	at sun.nio.ch.Net.serverSocket(Net.java:445)
>> 	at sun.nio.ch.AsynchronousServerSocketChannelImpl.<init>(AsynchronousServerSocketChannelImpl.java:71)
>> 	at sun.nio.ch.WindowsAsynchronousServerSocketChannelImpl.<init>(WindowsAsynchronousServerSocketChannelImpl.java:69)
>> 	at sun.nio.ch.WindowsAsynchronousChannelProvider.openAsynchronousServerSocketChannel(WindowsAsynchronousChannelProvider.java:83)
>> 	at java.nio.channels.AsynchronousServerSocketChannel.open(AsynchronousServerSocketChannel.java:140)
>> 	at java.nio.channels.AsynchronousServerSocketChannel.open(AsynchronousServerSocketChannel.java:161)
>> 	at StressLoopback.main(StressLoopback.java:42)
> This seems to be from the fact that the new SIO_LOOPBACK_FAST_PATH IOCTL code is only supported on more modern windows systems. I'm wondering if we should change the src code to not attempt to use this option on older windows kernels or if I should just modify the testcase to not run the test on older windows systems ?
>
> regards,
> Sean.
>
>
>
> On 09/01/2015 16:25, Martin Sawicki (MS OPEN TECH) wrote:
>> Sean, thank you for the update and your assistance. Looking forward.
>>
>> -----Original Message-----
>> From: Seán Coffey [mailto:sean.coffey at oracle.com]
>> Sent: Friday, January 09, 2015 8:24 AM
>> To: Martin Sawicki (MS OPEN TECH); jdk7u-dev at openjdk.java.net
>> Cc: Valery Kopylov (Akvelon); Kirk Shoop (MS OPEN TECH)
>> Subject: Re: Backporting the TCP loopback fast path (Windows)
>> improvement to OpenJDK v7
>>
>> Hey Martin,
>>
>> I can help in getting this enhancement ported to jdk7u-dev. I'm just waiting on approval for use of new system property in jdk7u release.
>> Once I have that, I can get this in.
>>
>> regards,
>> Sean.
>>
>> On 08/01/15 20:01, Martin Sawicki (MS OPEN TECH) wrote:
>>> Hello again,
>>> We'd like to propose to back-port our TCP loopback fast path performance improvement for Windows that was recently accepted into OpenJDK v9 and v8 into v7.
>>> Just for reference, the original OpenJDK v9 fix just for reference can be found here: http://hg.openjdk.java.net/jdk9/dev/jdk/rev/26e6402772c8.
>>>
>>> Our suggested webrev patch file for OpenJDK *v7* is attached to this message, based on our understanding of the back-porting steps.
>>>
>>> Your review and acceptance of this contribution would be appreciated.
>>>
>>> Best regards,
>>> Martin Sawicki (and Kirk Shoop, and Valeriy Kopylov) Microsoft Open
>>> Technologies, Inc.
>>> A subsidiary of Microsoft Corp.
>>>