svn commit: r357051 - head/sys/dev/bge

[Gleb Smirnoff]

On Thu, Jan 23, 2020 at 05:09:14PM -1000, Jeff Roberson wrote:
J> While we don't have a policy strictly requiring reviews it is the norm to 
J> have substantial changes socialized and reviewed.  I appreciate the work 
J> that you are doing but it likely should've been discussed somewhere 
J> more publicly.  I apologized if I missed it but I don't see reference to 
J> anything.

That was https://reviews.freebsd.org/D23242

J> Architecturally I am more concerned with the coarseness of net_epoch and 
J> the duration of hold becoming a resource utilization problem in high 
J> turn-over workloads.  Like short connection tcp.  Has anyone done 
J> substantial testing here?  epoch as it is today will hold every free 
J> callback for a minimum of several clock ticks and a maximum of 2x the 
J> duration of the longest epoch section time.  With preemption, etc. this 
J> could be 100s of ms of PCBs held.

We also are concerned about that theoretically. Haven't yet seen effect
in practice, but our sessions are mostly longer living. First we have the
tunable to limit batching. Second, there are some ideas on how to improve
the garbage collector performance if it becomes an issue.

-- 
Gleb Smirnoff