Venkat,

Please do not take these discussions off of the list.  We prefer to keep
this on the list as others may have similar questions.

I think there is some sort of misunderstanding here.  Are you telling me
that the interrupts per queue are 2000 interrupts/second giving you a
total of 4000 interrupts/second port, or that with 2 queues each queue
is operating at 1000 interrupts/second giving your a total number of
interrupts for the port of 2000 interrupts/second for the port?

None of the old drivers ever supported a per port interrupt rate.  So I
doubt it worked in 2.0.32.2.  If anything perhaps there was a bug that
was restricting you to only using one queue pair and that is the reason
why the number of interrupts matched.

The way the EITR registers work is that the lower 12 bits represent the
delay between interrupts in units of 256 nanoseconds.  So the FD0 value
for tx-0 below is roughly 1000 microseconds.  How is it you set that
value in the register?  It seems like only the first register is set to
that and the next is set to 100 microseconds which would give you an
interrupt rate of 10000 interrupts/second for tx-1.

If you are using "ethtool -c <dev> rx-usecs <delay> " to update the
interrupt throttle rate you will need to also use "tx-usecs <delay>" on
newer drivers when the Tx and Rx interrupt causes are split.

Thanks,

Alex

On 10/07/2013 10:17 AM, venkatakrishna pari wrote:
> HI ALexander,
>
> I invention to fire interrupt at 1000 interrupt/sec for Tx
> interrupts.  i worked two scenarios.  It is working in ixgbe of 3.16.1
> version.
>
> *scenario-1:*
>
> I sets ITR value is 1000 Interrupts/sec for one queue vectors. I
> configured  two queue vectors per ports.
>
> it likes eth6-TXRx-0 and eth6-TxRx-1.  But interrupt are firing at
> 2000 interrupt/sec.
>
>
> *scenario-11:*
>
> after that i configured four queue vectors likes
>
> eth6-rx-0,eth6-rx-1,eth6-tx-0 and eth6-tx-1. I sets ITR values
> eth6-tx-0 to 1000 interrupts/sec. But it is firing 4000 interrupt/sec
>
> The ITR value set in following registers
>
>         EITR[000]             00008890    eth6-rx-0
>         EITR[001]             000001e8    eth6-rx-0
>        *EITR[002]             09600f40    eth6-tx-0*   1000 interrupts
>         EITR[003]             000003d0    eth6-tx-1
>
> why i do understanding  firing at ITR * number queue vectors. But i
> worked in *scenario-II *old ixgbe driver of 2.0.32.2 version. It is
> working in that drivers.
>
> Could you please guide me how to resolve this issue.
>
> Thanks and Regard's
> venkat
>
>
>
> On Mon, Oct 7, 2013 at 9:33 PM, Alexander Duyck
> <[email protected] <mailto:[email protected]>> wrote:
>
>     On 10/03/2013 10:55 AM, venkatakrishna pari wrote:
>     > Hi ALL
>     >
>     > I have configured four Q vectors likes rx-0,rx-1,tx-0 and tx-1.
>     ITR value
>     > sets to 1000 interrupt/second. But Interrupt are firing at 4000
>     > interrupt/sec.  When  Q vector  changed  two Q vector TxRx-0 and
>     TxRx-1. It
>     > is firing at 2000 Interrupt/second. The interrupt firing rate is
>     equal to
>     > multiple of number Q vector. But ITR checked in  hardware
>     register[EITR]
>     > was set with 1000 interrupt/sec. I don't understand why it is
>     happening
>     > like that.
>     >
>     > Could you please guide to resolve this.
>     >
>     > Thanks in Advances.
>     >
>     > Thanks and Regard's
>     >
>
>     The ITR value for ixgbe is per vector, not per port.  The ixgbe
>     parts do
>     not support a global interrupt moderator, they only have one moderator
>     per q_vector.
>
>     Thanks,
>
>     Alex
>
>


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