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f4915455 YF |
1 | // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB |
2 | /* | |
3 | * Copyright (c) 2019, Mellanox Technologies inc. All rights reserved. | |
4 | */ | |
5 | ||
6 | #include <linux/dim.h> | |
7 | ||
8 | static int rdma_dim_step(struct dim *dim) | |
9 | { | |
10 | if (dim->tune_state == DIM_GOING_RIGHT) { | |
11 | if (dim->profile_ix == (RDMA_DIM_PARAMS_NUM_PROFILES - 1)) | |
12 | return DIM_ON_EDGE; | |
13 | dim->profile_ix++; | |
14 | dim->steps_right++; | |
15 | } | |
16 | if (dim->tune_state == DIM_GOING_LEFT) { | |
17 | if (dim->profile_ix == 0) | |
18 | return DIM_ON_EDGE; | |
19 | dim->profile_ix--; | |
20 | dim->steps_left++; | |
21 | } | |
22 | ||
23 | return DIM_STEPPED; | |
24 | } | |
25 | ||
26 | static int rdma_dim_stats_compare(struct dim_stats *curr, | |
27 | struct dim_stats *prev) | |
28 | { | |
29 | /* first stat */ | |
30 | if (!prev->cpms) | |
31 | return DIM_STATS_SAME; | |
32 | ||
33 | if (IS_SIGNIFICANT_DIFF(curr->cpms, prev->cpms)) | |
34 | return (curr->cpms > prev->cpms) ? DIM_STATS_BETTER : | |
35 | DIM_STATS_WORSE; | |
36 | ||
37 | if (IS_SIGNIFICANT_DIFF(curr->cpe_ratio, prev->cpe_ratio)) | |
38 | return (curr->cpe_ratio > prev->cpe_ratio) ? DIM_STATS_BETTER : | |
39 | DIM_STATS_WORSE; | |
40 | ||
41 | return DIM_STATS_SAME; | |
42 | } | |
43 | ||
44 | static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim) | |
45 | { | |
46 | int prev_ix = dim->profile_ix; | |
47 | u8 state = dim->tune_state; | |
48 | int stats_res; | |
49 | int step_res; | |
50 | ||
51 | if (state != DIM_PARKING_ON_TOP && state != DIM_PARKING_TIRED) { | |
52 | stats_res = rdma_dim_stats_compare(curr_stats, | |
53 | &dim->prev_stats); | |
54 | ||
55 | switch (stats_res) { | |
56 | case DIM_STATS_SAME: | |
57 | if (curr_stats->cpe_ratio <= 50 * prev_ix) | |
58 | dim->profile_ix = 0; | |
59 | break; | |
60 | case DIM_STATS_WORSE: | |
61 | dim_turn(dim); | |
4c1ca831 | 62 | fallthrough; |
f4915455 YF |
63 | case DIM_STATS_BETTER: |
64 | step_res = rdma_dim_step(dim); | |
65 | if (step_res == DIM_ON_EDGE) | |
66 | dim_turn(dim); | |
67 | break; | |
68 | } | |
69 | } | |
70 | ||
71 | dim->prev_stats = *curr_stats; | |
72 | ||
73 | return dim->profile_ix != prev_ix; | |
74 | } | |
75 | ||
76 | void rdma_dim(struct dim *dim, u64 completions) | |
77 | { | |
78 | struct dim_sample *curr_sample = &dim->measuring_sample; | |
79 | struct dim_stats curr_stats; | |
80 | u32 nevents; | |
81 | ||
82 | dim_update_sample_with_comps(curr_sample->event_ctr + 1, 0, 0, | |
83 | curr_sample->comp_ctr + completions, | |
84 | &dim->measuring_sample); | |
85 | ||
86 | switch (dim->state) { | |
87 | case DIM_MEASURE_IN_PROGRESS: | |
88 | nevents = curr_sample->event_ctr - dim->start_sample.event_ctr; | |
89 | if (nevents < DIM_NEVENTS) | |
90 | break; | |
91 | dim_calc_stats(&dim->start_sample, curr_sample, &curr_stats); | |
92 | if (rdma_dim_decision(&curr_stats, dim)) { | |
93 | dim->state = DIM_APPLY_NEW_PROFILE; | |
94 | schedule_work(&dim->work); | |
95 | break; | |
96 | } | |
4c1ca831 | 97 | fallthrough; |
f4915455 YF |
98 | case DIM_START_MEASURE: |
99 | dim->state = DIM_MEASURE_IN_PROGRESS; | |
100 | dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0, | |
101 | curr_sample->comp_ctr, | |
102 | &dim->start_sample); | |
103 | break; | |
104 | case DIM_APPLY_NEW_PROFILE: | |
105 | break; | |
106 | } | |
107 | } | |
108 | EXPORT_SYMBOL(rdma_dim); |