1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (c) 2019, Mellanox Technologies inc. All rights reserved.
4*4882a593Smuzhiyun */
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun #include <linux/dim.h>
7*4882a593Smuzhiyun
rdma_dim_step(struct dim * dim)8*4882a593Smuzhiyun static int rdma_dim_step(struct dim *dim)
9*4882a593Smuzhiyun {
10*4882a593Smuzhiyun if (dim->tune_state == DIM_GOING_RIGHT) {
11*4882a593Smuzhiyun if (dim->profile_ix == (RDMA_DIM_PARAMS_NUM_PROFILES - 1))
12*4882a593Smuzhiyun return DIM_ON_EDGE;
13*4882a593Smuzhiyun dim->profile_ix++;
14*4882a593Smuzhiyun dim->steps_right++;
15*4882a593Smuzhiyun }
16*4882a593Smuzhiyun if (dim->tune_state == DIM_GOING_LEFT) {
17*4882a593Smuzhiyun if (dim->profile_ix == 0)
18*4882a593Smuzhiyun return DIM_ON_EDGE;
19*4882a593Smuzhiyun dim->profile_ix--;
20*4882a593Smuzhiyun dim->steps_left++;
21*4882a593Smuzhiyun }
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun return DIM_STEPPED;
24*4882a593Smuzhiyun }
25*4882a593Smuzhiyun
rdma_dim_stats_compare(struct dim_stats * curr,struct dim_stats * prev)26*4882a593Smuzhiyun static int rdma_dim_stats_compare(struct dim_stats *curr,
27*4882a593Smuzhiyun struct dim_stats *prev)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun /* first stat */
30*4882a593Smuzhiyun if (!prev->cpms)
31*4882a593Smuzhiyun return DIM_STATS_SAME;
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun if (IS_SIGNIFICANT_DIFF(curr->cpms, prev->cpms))
34*4882a593Smuzhiyun return (curr->cpms > prev->cpms) ? DIM_STATS_BETTER :
35*4882a593Smuzhiyun DIM_STATS_WORSE;
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun if (IS_SIGNIFICANT_DIFF(curr->cpe_ratio, prev->cpe_ratio))
38*4882a593Smuzhiyun return (curr->cpe_ratio > prev->cpe_ratio) ? DIM_STATS_BETTER :
39*4882a593Smuzhiyun DIM_STATS_WORSE;
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun return DIM_STATS_SAME;
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun
rdma_dim_decision(struct dim_stats * curr_stats,struct dim * dim)44*4882a593Smuzhiyun static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun int prev_ix = dim->profile_ix;
47*4882a593Smuzhiyun u8 state = dim->tune_state;
48*4882a593Smuzhiyun int stats_res;
49*4882a593Smuzhiyun int step_res;
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun if (state != DIM_PARKING_ON_TOP && state != DIM_PARKING_TIRED) {
52*4882a593Smuzhiyun stats_res = rdma_dim_stats_compare(curr_stats,
53*4882a593Smuzhiyun &dim->prev_stats);
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun switch (stats_res) {
56*4882a593Smuzhiyun case DIM_STATS_SAME:
57*4882a593Smuzhiyun if (curr_stats->cpe_ratio <= 50 * prev_ix)
58*4882a593Smuzhiyun dim->profile_ix = 0;
59*4882a593Smuzhiyun break;
60*4882a593Smuzhiyun case DIM_STATS_WORSE:
61*4882a593Smuzhiyun dim_turn(dim);
62*4882a593Smuzhiyun /* fall through */
63*4882a593Smuzhiyun case DIM_STATS_BETTER:
64*4882a593Smuzhiyun step_res = rdma_dim_step(dim);
65*4882a593Smuzhiyun if (step_res == DIM_ON_EDGE)
66*4882a593Smuzhiyun dim_turn(dim);
67*4882a593Smuzhiyun break;
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun }
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun dim->prev_stats = *curr_stats;
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun return dim->profile_ix != prev_ix;
74*4882a593Smuzhiyun }
75*4882a593Smuzhiyun
rdma_dim(struct dim * dim,u64 completions)76*4882a593Smuzhiyun void rdma_dim(struct dim *dim, u64 completions)
77*4882a593Smuzhiyun {
78*4882a593Smuzhiyun struct dim_sample *curr_sample = &dim->measuring_sample;
79*4882a593Smuzhiyun struct dim_stats curr_stats;
80*4882a593Smuzhiyun u32 nevents;
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun dim_update_sample_with_comps(curr_sample->event_ctr + 1, 0, 0,
83*4882a593Smuzhiyun curr_sample->comp_ctr + completions,
84*4882a593Smuzhiyun &dim->measuring_sample);
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun switch (dim->state) {
87*4882a593Smuzhiyun case DIM_MEASURE_IN_PROGRESS:
88*4882a593Smuzhiyun nevents = curr_sample->event_ctr - dim->start_sample.event_ctr;
89*4882a593Smuzhiyun if (nevents < DIM_NEVENTS)
90*4882a593Smuzhiyun break;
91*4882a593Smuzhiyun dim_calc_stats(&dim->start_sample, curr_sample, &curr_stats);
92*4882a593Smuzhiyun if (rdma_dim_decision(&curr_stats, dim)) {
93*4882a593Smuzhiyun dim->state = DIM_APPLY_NEW_PROFILE;
94*4882a593Smuzhiyun schedule_work(&dim->work);
95*4882a593Smuzhiyun break;
96*4882a593Smuzhiyun }
97*4882a593Smuzhiyun /* fall through */
98*4882a593Smuzhiyun case DIM_START_MEASURE:
99*4882a593Smuzhiyun dim->state = DIM_MEASURE_IN_PROGRESS;
100*4882a593Smuzhiyun dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0,
101*4882a593Smuzhiyun curr_sample->comp_ctr,
102*4882a593Smuzhiyun &dim->start_sample);
103*4882a593Smuzhiyun break;
104*4882a593Smuzhiyun case DIM_APPLY_NEW_PROFILE:
105*4882a593Smuzhiyun break;
106*4882a593Smuzhiyun }
107*4882a593Smuzhiyun }
108*4882a593Smuzhiyun EXPORT_SYMBOL(rdma_dim);
109