Schedule for releases

Robert Watson rwatson at
Wed Dec 22 20:57:32 UTC 2010

On Wed, 22 Dec 2010, Mike Karels wrote:

> - We sometimes back-port other changes, such as TCP locking fixes that help 
> performance.  Considering some such things for MFC would be desirable.

Just to comment on the specifics of this one: over the cource of 6.x, 7.x, and 
8.x, I non-trivially improved locking in the TCP/UDP code.  Some of those 
changes could be backported -- others couldn't be.  Part of the reason I 
didn't merge some changes was our increasing attempt to provide stable KPIs 
and KBIs for kernel modules, especially as TCP offload support in device 
drivers became a reality.

We're now going to hit the same issue in 9.x: I'm about to commit significant 
network stack locking and work distribution changes to improve TCP and UDP 
scalability, leading to multiplied performance on parallel systems.  As of the 
interpretation of KPI/KBI compatibility we have today, these cannot be MFC'd 
to 8.x.  I think there's a motivation to revisit our thinking on KPI/KBI so 
that we can merge them to 8.x in the future; I'll say more about this on the 
net@ mailing list in a month or so once the changes are in 9.x and have shaken 
out a bit.


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