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