// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
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/*
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* Copyright (c) 2019, Mellanox Technologies inc. All rights reserved.
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*/
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#include <linux/dim.h>
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static int rdma_dim_step(struct dim *dim)
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{
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if (dim->tune_state == DIM_GOING_RIGHT) {
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if (dim->profile_ix == (RDMA_DIM_PARAMS_NUM_PROFILES - 1))
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return DIM_ON_EDGE;
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dim->profile_ix++;
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dim->steps_right++;
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}
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if (dim->tune_state == DIM_GOING_LEFT) {
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if (dim->profile_ix == 0)
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return DIM_ON_EDGE;
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dim->profile_ix--;
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dim->steps_left++;
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}
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return DIM_STEPPED;
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}
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static int rdma_dim_stats_compare(struct dim_stats *curr,
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struct dim_stats *prev)
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{
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/* first stat */
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if (!prev->cpms)
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return DIM_STATS_SAME;
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if (IS_SIGNIFICANT_DIFF(curr->cpms, prev->cpms))
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return (curr->cpms > prev->cpms) ? DIM_STATS_BETTER :
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DIM_STATS_WORSE;
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if (IS_SIGNIFICANT_DIFF(curr->cpe_ratio, prev->cpe_ratio))
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return (curr->cpe_ratio > prev->cpe_ratio) ? DIM_STATS_BETTER :
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DIM_STATS_WORSE;
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return DIM_STATS_SAME;
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}
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static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim)
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{
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int prev_ix = dim->profile_ix;
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u8 state = dim->tune_state;
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int stats_res;
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int step_res;
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if (state != DIM_PARKING_ON_TOP && state != DIM_PARKING_TIRED) {
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stats_res = rdma_dim_stats_compare(curr_stats,
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&dim->prev_stats);
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switch (stats_res) {
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case DIM_STATS_SAME:
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if (curr_stats->cpe_ratio <= 50 * prev_ix)
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dim->profile_ix = 0;
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break;
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case DIM_STATS_WORSE:
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dim_turn(dim);
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/* fall through */
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case DIM_STATS_BETTER:
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step_res = rdma_dim_step(dim);
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if (step_res == DIM_ON_EDGE)
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dim_turn(dim);
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break;
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}
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}
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dim->prev_stats = *curr_stats;
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return dim->profile_ix != prev_ix;
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}
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void rdma_dim(struct dim *dim, u64 completions)
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{
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struct dim_sample *curr_sample = &dim->measuring_sample;
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struct dim_stats curr_stats;
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u32 nevents;
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dim_update_sample_with_comps(curr_sample->event_ctr + 1, 0, 0,
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curr_sample->comp_ctr + completions,
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&dim->measuring_sample);
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switch (dim->state) {
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case DIM_MEASURE_IN_PROGRESS:
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nevents = curr_sample->event_ctr - dim->start_sample.event_ctr;
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if (nevents < DIM_NEVENTS)
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break;
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dim_calc_stats(&dim->start_sample, curr_sample, &curr_stats);
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if (rdma_dim_decision(&curr_stats, dim)) {
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dim->state = DIM_APPLY_NEW_PROFILE;
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schedule_work(&dim->work);
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break;
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}
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/* fall through */
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case DIM_START_MEASURE:
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dim->state = DIM_MEASURE_IN_PROGRESS;
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dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0,
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curr_sample->comp_ctr,
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&dim->start_sample);
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break;
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case DIM_APPLY_NEW_PROFILE:
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break;
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}
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}
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EXPORT_SYMBOL(rdma_dim);
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