> From: Brown, Aaron F
> Sent: Friday, April 13, 2018 7:28 PM
> To: 'Vinicius Costa Gomes' <[email protected]>; intel-wired-
> [email protected]
> Cc: Gomes, Vinicius <[email protected]>; Kirsher, Jeffrey T
> <[email protected]>; [email protected]; Sanchez-Palencia,
> Jesus <[email protected]>; Guedes, Andre
> <[email protected]>
> Subject: RE: [next-queue PATCH] igb: Fix the transmission mode of queue 0
> for Qav mode
>
> > From: [email protected] [mailto:netdev-
> > [email protected]] On Behalf Of Vinicius Costa Gomes
> > Sent: Friday, March 30, 2018 5:07 PM
> > To: [email protected]
> > Cc: Gomes, Vinicius <[email protected]>; Kirsher, Jeffrey T
> > <[email protected]>; [email protected]; Sanchez-Palencia,
> > Jesus <[email protected]>; Guedes, Andre
> > <[email protected]>
> > Subject: [next-queue PATCH] igb: Fix the transmission mode of queue 0 for
> > Qav mode
> >
> > When Qav mode is enabled, queue 0 should be kept on Stream
> Reservation
> > mode. From the i210 datasheet, section 8.12.19:
> >
> > "Note: Queue0 QueueMode must be set to 1b when TransmitMode is set
> to
> > Qav." ("QueueMode 1b" represents the Stream Reservation mode)
> >
> > The solution is to give queue 0 the all the credits it might need, so
> > it has priority over queue 1.
> >
> > A situation where this can happen is when cbs is "installed" only on
> > queue 1, leaving queue 0 alone. For example:
> >
> > $ tc qdisc replace dev enp2s0 handle 100: parent root mqprio num_tc 3 \
> > map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@2 hw 0
> >
> > $ tc qdisc replace dev enp2s0 parent 100:2 cbs locredit -1470 \
> > hicredit 30 sendslope -980000 idleslope 20000 offload 1
> >
> > Signed-off-by: Vinicius Costa Gomes <[email protected]>
> > ---
> > drivers/net/ethernet/intel/igb/igb_main.c | 17 ++++++++++++++++-
> > 1 file changed, 16 insertions(+), 1 deletion(-)
> >
>
> Tested by: Aaron Brown <[email protected]>
Tested-by: Aaron Brown <[email protected]>
