[PATCHES] SMB3 Multi-Channel: connection passing and enablement

[Youzhong Yang]

Hi Michael,

> Could well be that some buffers are filled on the Windows/receiving side and a disk is becoming a bottleneck?

This is exactly what we found out. I wrote a Windows program to read from Samba with no writing to local disk, I saw two NICs were receiving data almost in full line speed.

We've also tested this Multi-Channel version using our build and test system and some Windows 10 hosts, so far so good, there's no issue found.

This MC feature is really nice! I am just wondering why it can't get into Samba 4.4.

Please let me know if you'd have anything particular that needs us to test. 

Thanks,

Youzhong

-----Original Message-----
From: Michael Adam [mailto:obnox at samba.org] 
Sent: Wednesday, February 10, 2016 2:05 AM
To: Youzhong Yang <Youzhong.Yang at mathworks.com>
Cc: samba-technical at lists.samba.org
Subject: Re: [PATCHES] SMB3 Multi-Channel: connection passing and enablement

On 2016-02-01 at 17:58 +0000, Youzhong Yang wrote:
> Hi Michael,

Hi Youzhong Yang,

Thanks for testing the feature and for your feed-back!

> I applied your patch smb3-mc-enable.patch to the master branch, 
> successfully built a samba version on our SmartOS box and tested it. 
> It works! I can see network traffic goes through two vNIC interfaces.
> 
> What I did is copying six 4GB files from the server to a Windows 10 
> host with two physical NICs (Intel(R) 82574L Gigabit). Each interface 
> was transferring ~120M bytes per second, which is almost its line 
> speed, for approximately 30 seconds. After 30 seconds, the speed 
> dropped to ~30M bytes/second. Please see attached nic stats file for 
> your reference.
> 
> I cannot explain this behavior. I am just wondering if it is related 
> to Windows 10 network throttling or something like that, but I 
> couldn't find a knob to turn it off.

Does the throttling only happen with multi-channel enabled or also without it?

Could well be that some buffers are filled on the Windows/receiving side and a disk is becoming a bottleneck?

What happens if you write to Samba instead of reading from it?

What happens if you write to a ramdisk?

Just some thoughts.

Michael