[rds-devel] Re: [PATCH RFC RDS/IB] version 2. increase numberof unsignaled work requests

[Richard Frank]

The RDS driver that was originally contributed to OpenIB. 

On Thu, 2007-01-25 at 09:00 -0800, Carl Yang (caryang) wrote:
> Rick,
> 
> What ref driver are you referring to?  The driver code from Oracle or
> SSRDS?
> 
> Regards,
> Carl 
> 
> -----Original Message-----
> From: rds-devel-bounces at oss.oracle.com
> [mailto:rds-devel-bounces at oss.oracle.com] On Behalf Of Richard Frank
> Sent: Thursday, January 25, 2007 8:45 AM
> To: vlad at dev.mellanox.co.il
> Cc: rds-devel at oss.oracle.com
> Subject: Re: [rds-devel] Re: [PATCH RFC RDS/IB] version 2. increase
> numberof unsignaled work requests
> 
> On Thu, 2007-01-25 at 11:25 +0200, Vladimir Sokolovsky wrote:
> > 
> > Although the code does not have interleaving fragments from different 
> > messages, it seems that multiple RDS messages can be in-flight 
> > simultaneously because rds_send_xmit() does not wait for completions:
> > it
> > continues to process the next message as soon as the transport layer 
> > (e.g., IB) reports that the messages "have been sent".
> > With IB, it just means that the messages have been scheduled for 
> > transmission by the HW.
> > 
> > Did I miss something?
> 
> Another important consideration is RNR retry period. Assuming there is
> no flow control in the RDS wire protocol (was none in the ref driver)
> then we are dependent on fast RNR recovery (IB flow control). 
> 
> The ref RDS driver would set this retry period to be a minimum value -
> so sender retries very quickly. This change had a large impact on thru-
> put. 
> 
> 
> 
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