net/mlx5e: Added BW check for DIM decision mechanism

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[ Upstream commit c3164d2fc4 ]

DIM (Dynamically-tuned Interrupt Moderation) is a mechanism designed for
changing the channel interrupt moderation values in order to reduce CPU
overhead for all traffic types.
Until now only interrupt and packet rate were sampled.
We found a scenario on which we get a false indication since a change in
DIM caused more aggregation and reduced packet rate while increasing BW.

We now regard a change as succesfull iff:
current_BW > (prev_BW + threshold) or
current_BW ~= prev_BW and current_PR > (prev_PR + threshold) or
current_BW ~= prev_BW and current_PR ~= prev_PR and
    current_IR < (prev_IR - threshold)
Where BW = Bandwidth, PR = Packet rate and IR = Interrupt rate

Improvements (ConnectX-4Lx 25GbE, single RX queue, LRO off)
    --------------------------------------------------
    packet size | before[Mb/s] | after[Mb/s] | gain  |
    2B          | 343.4        | 359.4       |  4.5% |
    16B         | 2739.7       | 2814.8      |  2.7% |
    64B         | 9739         | 10185.3     |  4.5% |

Fixes: cb3c7fd4f8 ("net/mlx5e: Support adaptive RX coalescing")
Signed-off-by: Tal Gilboa <talgi@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Tal Gilboa 2017-05-15 14:13:16 +03:00 • committed by Greg Kroah-Hartman

parent 57360bc3c7

commit 9854e58659

2 changed files with 22 additions and 17 deletions

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2

drivers/net/ethernet/mellanox/mlx5/core/en.h

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37

drivers/net/ethernet/mellanox/mlx5/core/en_rx_am.c

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