net/mlx5e: Added BW check for DIM decision mechanism
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>
This commit is contained in:
parent
f729860a17
commit
c3164d2fc4
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@ -458,12 +458,14 @@ struct mlx5e_mpw_info {
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struct mlx5e_rx_am_stats {
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int ppms; /* packets per msec */
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int bpms; /* bytes per msec */
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int epms; /* events per msec */
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};
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struct mlx5e_rx_am_sample {
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ktime_t time;
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unsigned int pkt_ctr;
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unsigned int byte_ctr;
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u16 event_ctr;
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};
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@ -183,28 +183,27 @@ static void mlx5e_am_exit_parking(struct mlx5e_rx_am *am)
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mlx5e_am_step(am);
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}
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#define IS_SIGNIFICANT_DIFF(val, ref) \
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(((100 * abs((val) - (ref))) / (ref)) > 10) /* more than 10% difference */
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static int mlx5e_am_stats_compare(struct mlx5e_rx_am_stats *curr,
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struct mlx5e_rx_am_stats *prev)
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{
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int diff;
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if (!prev->ppms)
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return curr->ppms ? MLX5E_AM_STATS_BETTER :
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if (!prev->bpms)
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return curr->bpms ? MLX5E_AM_STATS_BETTER :
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MLX5E_AM_STATS_SAME;
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diff = curr->ppms - prev->ppms;
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if (((100 * abs(diff)) / prev->ppms) > 10) /* more than 10% diff */
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return (diff > 0) ? MLX5E_AM_STATS_BETTER :
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MLX5E_AM_STATS_WORSE;
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if (IS_SIGNIFICANT_DIFF(curr->bpms, prev->bpms))
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return (curr->bpms > prev->bpms) ? MLX5E_AM_STATS_BETTER :
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MLX5E_AM_STATS_WORSE;
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if (!prev->epms)
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return curr->epms ? MLX5E_AM_STATS_WORSE :
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MLX5E_AM_STATS_SAME;
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if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
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return (curr->ppms > prev->ppms) ? MLX5E_AM_STATS_BETTER :
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MLX5E_AM_STATS_WORSE;
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diff = curr->epms - prev->epms;
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if (((100 * abs(diff)) / prev->epms) > 10) /* more than 10% diff */
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return (diff < 0) ? MLX5E_AM_STATS_BETTER :
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MLX5E_AM_STATS_WORSE;
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if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms))
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return (curr->epms < prev->epms) ? MLX5E_AM_STATS_BETTER :
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MLX5E_AM_STATS_WORSE;
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return MLX5E_AM_STATS_SAME;
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}
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@ -266,6 +265,7 @@ static void mlx5e_am_sample(struct mlx5e_rq *rq,
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{
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s->time = ktime_get();
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s->pkt_ctr = rq->stats.packets;
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s->byte_ctr = rq->stats.bytes;
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s->event_ctr = rq->cq.event_ctr;
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}
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@ -278,12 +278,15 @@ static void mlx5e_am_calc_stats(struct mlx5e_rx_am_sample *start,
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/* u32 holds up to 71 minutes, should be enough */
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u32 delta_us = ktime_us_delta(end->time, start->time);
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unsigned int npkts = end->pkt_ctr - start->pkt_ctr;
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unsigned int nbytes = end->byte_ctr - start->byte_ctr;
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if (!delta_us)
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return;
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curr_stats->ppms = (npkts * USEC_PER_MSEC) / delta_us;
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curr_stats->epms = (MLX5E_AM_NEVENTS * USEC_PER_MSEC) / delta_us;
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curr_stats->ppms = DIV_ROUND_UP(npkts * USEC_PER_MSEC, delta_us);
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curr_stats->bpms = DIV_ROUND_UP(nbytes * USEC_PER_MSEC, delta_us);
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curr_stats->epms = DIV_ROUND_UP(MLX5E_AM_NEVENTS * USEC_PER_MSEC,
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delta_us);
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}
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void mlx5e_rx_am_work(struct work_struct *work)
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