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| 3 | * Copyright (c) 2019, Mellanox Technologies inc. All rights reserved.
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| 4 |
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| 5 |
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| 6 | #include <linux/dim.h>
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| 7 |
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| 8 | static int rdma_dim_step(struct dim *dim)
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| 9 | {
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| 10 | if (dim->tune_state == DIM_GOING_RIGHT) {
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| 11 | if (dim->profile_ix == (RDMA_DIM_PARAMS_NUM_PROFILES - 1))
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| 12 | return DIM_ON_EDGE;
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| 13 | dim->profile_ix++;
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| 14 | dim->steps_right++;
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| 15 | }
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| 16 | if (dim->tune_state == DIM_GOING_LEFT) {
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| 17 | if (dim->profile_ix == 0)
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| 18 | return DIM_ON_EDGE;
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| 19 | dim->profile_ix--;
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| 20 | dim->steps_left++;
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| 21 | }
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| 22 |
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| 23 | return DIM_STEPPED;
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| 24 | }
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| 25 |
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| 26 | static int rdma_dim_stats_compare(struct dim_stats *curr,
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| 27 | struct dim_stats *prev)
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| 28 | {
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| 29 |
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| 30 | if (!prev->cpms)
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| 31 | return DIM_STATS_SAME;
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| 32 |
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| 33 | if (IS_SIGNIFICANT_DIFF(curr->cpms, prev->cpms))
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| 34 | return (curr->cpms > prev->cpms) ? DIM_STATS_BETTER :
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| 35 | DIM_STATS_WORSE;
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| 36 |
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| 37 | if (IS_SIGNIFICANT_DIFF(curr->cpe_ratio, prev->cpe_ratio))
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| 38 | return (curr->cpe_ratio > prev->cpe_ratio) ? DIM_STATS_BETTER :
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| 39 | DIM_STATS_WORSE;
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| 40 |
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| 41 | return DIM_STATS_SAME;
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| 42 | }
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| 43 |
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| 44 | static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim)
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| 45 | {
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| 46 | int prev_ix = dim->profile_ix;
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| 47 | u8 state = dim->tune_state;
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| 48 | int stats_res;
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| 49 | int step_res;
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| 50 |
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| 51 | if (state != DIM_PARKING_ON_TOP && state != DIM_PARKING_TIRED) {
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| 52 | stats_res = rdma_dim_stats_compare(curr_stats,
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| 53 | &dim->prev_stats);
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| 54 |
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| 55 | switch (stats_res) {
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| 56 | case DIM_STATS_SAME:
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| 57 | if (curr_stats->cpe_ratio <= 50 * prev_ix)
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| 58 | dim->profile_ix = 0;
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| 59 | break;
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| 60 | case DIM_STATS_WORSE:
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| 61 | dim_turn(dim);
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| 62 | fallthrough;
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| 63 | case DIM_STATS_BETTER:
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| 64 | step_res = rdma_dim_step(dim);
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| 65 | if (step_res == DIM_ON_EDGE)
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| 66 | dim_turn(dim);
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| 67 | break;
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| 68 | }
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| 69 | }
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| 70 |
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| 71 | dim->prev_stats = *curr_stats;
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| 72 |
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| 73 | return dim->profile_ix != prev_ix;
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| 74 | }
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| 75 |
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| 76 | void rdma_dim(struct dim *dim, u64 completions)
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| 77 | {
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| 78 | struct dim_sample *curr_sample = &dim->measuring_sample;
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| 79 | struct dim_stats curr_stats;
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| 80 | u32 nevents;
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| 81 |
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| 82 | dim_update_sample_with_comps(curr_sample->event_ctr + 1, 0, 0,
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| 83 | curr_sample->comp_ctr + completions,
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| 84 | &dim->measuring_sample);
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| 85 |
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| 86 | switch (dim->state) {
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| 87 | case DIM_MEASURE_IN_PROGRESS:
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| 88 | nevents = curr_sample->event_ctr - dim->start_sample.event_ctr;
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| 89 | if (nevents < DIM_NEVENTS)
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| 90 | break;
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| 91 | if (!dim_calc_stats(&dim->start_sample, curr_sample, &curr_stats))
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| 92 | break;
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| 93 | if (rdma_dim_decision(&curr_stats, dim)) {
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| 94 | dim->state = DIM_APPLY_NEW_PROFILE;
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| 95 | schedule_work(&dim->work);
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| 96 | break;
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| 97 | }
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| 98 | fallthrough;
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| 99 | case DIM_START_MEASURE:
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| 100 | dim->state = DIM_MEASURE_IN_PROGRESS;
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| 101 | dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0,
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| 102 | curr_sample->comp_ctr,
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| 103 | &dim->start_sample);
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| 104 | break;
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| 105 | case DIM_APPLY_NEW_PROFILE:
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| 106 | break;
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| 107 | }
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| 108 | }
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| 109 | EXPORT_SYMBOL(rdma_dim);
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