On Thu, 2016-03-24 at 11:20 -0700, Tolga Ceylan wrote:

On Thu, Mar 24, 2016 at 10:55 AM, Daniel Borkmann [off-list ref] wrote:

quoted

On 03/24/2016 06:26 PM, Tom Herbert wrote:

quoted

I completely agree with this, but I wonder if we now need a repository
of useful BPF modules. So in the case of implementing functionality
like in SO_REUSEPORT_LISTEN_OFF that might just become a common BPF
program we could direct people to use.

Good point. There's tools/testing/selftests/net/ containing already
reuseport
BPF example, maybe it could be extended.

I would appreciate a conceptual description on how this would work
especially for a common scenario
as described by Willy. My initial impression was that a coordinator
(master) process takes this
responsibility to adjust BPF filters as children come and go.

Two popular software has similar use cases: nginx and haproxy. Another
concern is with the
introduction of BPF itself, should we expect a performance drop in
these applications?

Just to make it clear : 

BPF allows proper siloing if you have multi queue NIC, instead of a
random hashing that was reducing performance.

BPF on SO_REUSEPORT can reduce false sharing between cpus and increase
NUMA locality.

BPF allows us to use whatever number of silos, without having to scan
the whole socket list for every incoming packet.

Huge gain really.