Windows Redirector Abnomality

[Jeremy Allison]

On Tue, Aug 19, 2008 at 05:15:12PM -0700, Ephi Dror wrote:
> 
> Hello Samba,
> 
> We are running some performance testing in having the following question:
> 
> When an application on Windows clients sequentially writes to a file
> on a remote system (samba server) using block (IO) size of 256KB, the Windows
> Redirector splits each request into 4 SMB_WRITE_ANDX requests each
> of size 64KB and sends the requests in parallel to the remote server
> without waiting for response. Here is the network capture:
> 
> Application write request (256KB):
>     Send SMB_WRITE_ANDX (64KB)
>     Send SMB_WRITE_ANDX( 64KB)
>     Send SMB_WRITE_ANDX (64KB)
>     Send SMB_WRITE_ANDX (64KB)
>     Wait for replies
> Return result to application
> 
> When an application on a Windows clients sequentially reads from a file
> on a remote system (samba server) using block (IO) size of 256KB, the Windows
> Redirector splits each request into 4 SMB_READ_ANDX requests each of
> size 60KB and 1 request of size 16KB. In addition, the read requests are
> not sent in parallel.
> 
> Application read request (256KB):
>     Send SMB_READ_ANDX (60KB)
>     Wait for reply
>     Send SMB_READ_ANDX (60KB)
>     Wait for reply
>     Send SMB_READ_ANDX (60KB)
>     Wait for reply
>     Send SMB_READ_ANDX (60KB)
>     Wait for reply
>     Send SMB_READ_ANDX (16KB)
>     Wait for reply
> Return result to application
> 
> Is there any Registry setting on the Windows client to make reads in
> parallel as well?
> 
> The remote server has advertized maxmumim multiplexed commands 50.

Which Windows client ? What is the application ? Using more
threads on the Windows side can make a difference here..

Jeremy.