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

[Seán Coffey]

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.
>>