On 9/11/2017 8:53 PM, Eric Dumazet wrote:
On Mon, 2017-09-11 at 20:12 -0700, Tom Herbert wrote:
Two ints in sock_common for this purpose is quite expensive and the
use case for this is limited-- even if a RX->TX queue mapping were
introduced to eliminate the queue pair assumption this still won't
help if the receive and transmit interfaces are different for the
connection. I think we really need to see some very compelling results
to be able to justify this.
Will try to collect and post some perf data with symmetric queue
configuration.
Yes, this is unreasonable cost.
XPS should really cover the case already.
Eric,
Can you clarify how XPS covers the RX-> TX queue mapping case?
Is it possible to configure XPS to select TX queue based on the RX queue
of a flow?
IIUC, it is based on the CPU of the thread doing the transmit OR based
on skb->priority to TC mapping?
It may be possible to get this effect if the the threads are pinned to a
core, but if the app threads are
freely moving, i am not sure how XPS can be configured to select the TX
queue based on the RX queue of a flow.
Thanks
Sridhar
