Hi Kevin
I did some basic testing and parsed all the code.
I have some high level comments, below.
I’ll add the other comments tomorrow.
1/ The redistribution is based on the last interval – I wonder if a number of
intervals may be better.
Possibly a single interval could result in a skewed decision ?
2/ I see a rebalance command added that can be used other than at
reconfiguration time.
Rather than for testing (per the patch use case), maybe this could be used
as maintenance command when combined
with https://patchwork.ozlabs.org/patch/768757/ ?
If this is the case, patch 6 could have more description how best to do that.
I will look at Sugesh’s patch tomorrow as well so we can expedite.
Thanks Darrell
-----Original Message-----
From: <ovs-dev-boun...@openvswitch.org> on behalf of Kevin Traynor
<ktray...@redhat.com>
Date: Wednesday, August 9, 2017 at 8:45 AM
To: "d...@openvswitch.org" <d...@openvswitch.org>, "ian.sto...@intel.com"
<ian.sto...@intel.com>, "jan.scheur...@ericsson.com"
<jan.scheur...@ericsson.com>, "bhanuprakash.bodire...@intel.com"
<bhanuprakash.bodire...@intel.com>, "mark.b.kavan...@intel.com"
<mark.b.kavan...@intel.com>, "gvrose8...@gmail.com" <gvrose8...@gmail.com>
Subject: [ovs-dev] [PATCH v4 0/6] OVS-DPDK rxq to pmd assignment
improvements.
For the DPDK datapath, by default rxqs are assigned to available pmds
in round robin order with no weight or priority.
It can happen that some very busy queues are handled by one pmd which
does not have enough cycles to prevent packets being dropped on them.
While at the same time another pmd which handles queues with no traffic
on them is essentially idle.
Rxq to pmd assignment happens as a result of a number of events and
when it does, the same unweighted round robin approach is applied
each time.
This patchset proposes to improve the round robin nature of rxq to pmd
assignment by counting the processing cycles used by the rxqs during
their operation and incorporating that data into assignment.
Before assigning in a round robin manner, the rxqs will be sorted in
order of the processing cycles they have been consuming. Assuming
multiple pmds, this ensures that the rxqs measured to be using the
most processing cycles will be assigned to different cores.
In some cases the measured cycles for an rxq may be not available as
the rxq is new or may not be useful for assignment as traffic patterns
may change. In those cases the code will essentially fallback to being
round round similar to what currently exists. However, in the case
where data is available and a reliable indication of future rxq cycles
consumption, rxq to pmd distribution will be much improved.
V3 -> V4
========
4/6
Rebased to accomodate new cross numa assigment.
V2 -> V3
========
Dropped v2 1/7 as not reusing dpcls optimisation interval anymore
2/6
Moved unused functions to 3/6 to avoid compiler warning
3/6
Made pmd rxq interval independent from dpcls opt interval
4/6
Moved docs about rebalance command to when it is available in 6/6
Added logging info for pmd to rxq assignment
5/6
Added an example to docs
6/6
Noted in commit msg that Jan requested this for testing purposes
V1 -> V2
========
Dropped Ciara's patch to change how pmd cycles are counted as it merged.
6/7: Rebased unit tests.
Kevin Traynor (6):
dpif-netdev: Change polled_queue to use dp_netdev_rxq.
dpif-netdev: Add rxq processing cycle counters.
dpif-netdev: Count the rxq processing cycles for an rxq.
dpif-netdev: Change rxq_scheduling to use rxq processing cycles.
dpif-netdev: Change pmd selection order.
dpif-netdev: Add ovs-appctl dpif-netdev/pmd-rxq-rebalance.
Documentation/howto/dpdk.rst | 26 +++++
lib/dpif-netdev.c | 252
+++++++++++++++++++++++++++++++++++--------
tests/pmd.at | 2 +-
vswitchd/ovs-vswitchd.8.in | 2 +
4 files changed, 237 insertions(+), 45 deletions(-)
--
1.8.3.1
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