[Intel-wired-lan] [PATCH net-next v2 1/3] ice-linux: update dim usage and moderation

[Nguyen, Anthony L]

On Thu, 2021-08-19 at 20:55 +0000, Creeley, Brett wrote:
> > -----Original Message-----
> > From: Intel-wired-lan <intel-wired-lan-bounces at osuosl.org> On
> > Behalf Of Jesse Brandeburg
> > Sent: Thursday, August 19, 2021 12:30 PM
> > To: intel-wired-lan at lists.osuosl.org
> > Subject: [Intel-wired-lan] [PATCH net-next v2 1/3] ice-linux:
> > update dim usage and moderation
> 
> I think the subject should be "ice: ..." instead of "ice-linux: ...".
> Same
> goes for 2/3 and 3/3.

I agree with Brett. ice, not ice-linux. I was going to fix that up
myself, however, this isn't applying after Maciej's series [1]. It
looked largely due to the split of ice_ring [2], but I didn't see if
there were other conflicts. Could you update and accommodate the
series' changes so it'll apply?

Thanks,
Tony


[1] 
https://patchwork.ozlabs.org/project/intel-wired-lan/list/?series=258748
[2] https://patchwork.ozlabs.org/patch/1518639

> > The driver was having trouble with unreliable latency when doing
> > single
> > threaded ping-pong tests. This was root caused to the DIM algorithm
> > landing on a too slow interrupt value, which caused high latency,
> > and it
> > was especially present when queues were being switched frequently
> > by the
> > scheduler as happens on default setups today.
> > 
> > In attempting to improve this, we allow the upper rate limit for
> > interrupts to move to rate limit of 4 microseconds as a max, which
> > means
> > that no vector can generate more than 250,000 interrupts per
> > second. The
> > old config was up to 100,000. The driver previously tried to
> > program the
> > rate limit too frequently and if the receive and transmit side were
> > both
> > active on the same vector, the INTRL would be set incorrectly, and
> > this
> > change fixes that issue as a side effect of the redesign.
> > 
> > This driver will operate from now on with a slightly changed DIM
> > table
> > with more emphasis towards latency sensitivity by having more table
> > entries with lower latency than with high latency (high being >= 64
> > microseconds).
> > 
> > The driver also resets the DIM algorithm state with a new stats set
> > when
> > there is no work done and the data becomes stale (older than 1
> > second),
> > for the respective receive or transmit portion of the interrupt.
> > 
> > Add a new helper for setting rate limit, which will be used more
> > in a followup patch.
> > 
> > Signed-off-by: Jesse Brandeburg <jesse.brandeburg at intel.com>
> > ---
> >  drivers/net/ethernet/intel/ice/ice_lib.c  |  25 +++++
> >  drivers/net/ethernet/intel/ice/ice_lib.h  |   1 +
> >  drivers/net/ethernet/intel/ice/ice_main.c | 118 ++++++++++++----
> > ------
> >  drivers/net/ethernet/intel/ice/ice_txrx.c |  73 ++++++-------
> >  4 files changed, 130 insertions(+), 87 deletions(-)
> 
> <snip>
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