xref: /openbmc/linux/lib/dim/net_dim.c (revision 162bd18e)
1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2 /*
3  * Copyright (c) 2018, Mellanox Technologies inc.  All rights reserved.
4  */
5 
6 #include <linux/dim.h>
7 
8 /*
9  * Net DIM profiles:
10  *        There are different set of profiles for each CQ period mode.
11  *        There are different set of profiles for RX/TX CQs.
12  *        Each profile size must be of NET_DIM_PARAMS_NUM_PROFILES
13  */
14 #define NET_DIM_PARAMS_NUM_PROFILES 5
15 #define NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE 256
16 #define NET_DIM_DEFAULT_TX_CQ_PKTS_FROM_EQE 128
17 #define NET_DIM_DEF_PROFILE_CQE 1
18 #define NET_DIM_DEF_PROFILE_EQE 1
19 
20 #define NET_DIM_RX_EQE_PROFILES { \
21 	{.usec = 1,   .pkts = NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE,}, \
22 	{.usec = 8,   .pkts = NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE,}, \
23 	{.usec = 64,  .pkts = NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE,}, \
24 	{.usec = 128, .pkts = NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE,}, \
25 	{.usec = 256, .pkts = NET_DIM_DEFAULT_RX_CQ_PKTS_FROM_EQE,}  \
26 }
27 
28 #define NET_DIM_RX_CQE_PROFILES { \
29 	{.usec = 2,  .pkts = 256,},             \
30 	{.usec = 8,  .pkts = 128,},             \
31 	{.usec = 16, .pkts = 64,},              \
32 	{.usec = 32, .pkts = 64,},              \
33 	{.usec = 64, .pkts = 64,}               \
34 }
35 
36 #define NET_DIM_TX_EQE_PROFILES { \
37 	{.usec = 1,   .pkts = NET_DIM_DEFAULT_TX_CQ_PKTS_FROM_EQE,},  \
38 	{.usec = 8,   .pkts = NET_DIM_DEFAULT_TX_CQ_PKTS_FROM_EQE,},  \
39 	{.usec = 32,  .pkts = NET_DIM_DEFAULT_TX_CQ_PKTS_FROM_EQE,},  \
40 	{.usec = 64,  .pkts = NET_DIM_DEFAULT_TX_CQ_PKTS_FROM_EQE,},  \
41 	{.usec = 128, .pkts = NET_DIM_DEFAULT_TX_CQ_PKTS_FROM_EQE,}   \
42 }
43 
44 #define NET_DIM_TX_CQE_PROFILES { \
45 	{.usec = 5,  .pkts = 128,},  \
46 	{.usec = 8,  .pkts = 64,},  \
47 	{.usec = 16, .pkts = 32,},  \
48 	{.usec = 32, .pkts = 32,},  \
49 	{.usec = 64, .pkts = 32,}   \
50 }
51 
52 static const struct dim_cq_moder
53 rx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
54 	NET_DIM_RX_EQE_PROFILES,
55 	NET_DIM_RX_CQE_PROFILES,
56 };
57 
58 static const struct dim_cq_moder
59 tx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
60 	NET_DIM_TX_EQE_PROFILES,
61 	NET_DIM_TX_CQE_PROFILES,
62 };
63 
64 struct dim_cq_moder
net_dim_get_rx_moderation(u8 cq_period_mode,int ix)65 net_dim_get_rx_moderation(u8 cq_period_mode, int ix)
66 {
67 	struct dim_cq_moder cq_moder = rx_profile[cq_period_mode][ix];
68 
69 	cq_moder.cq_period_mode = cq_period_mode;
70 	return cq_moder;
71 }
72 EXPORT_SYMBOL(net_dim_get_rx_moderation);
73 
74 struct dim_cq_moder
net_dim_get_def_rx_moderation(u8 cq_period_mode)75 net_dim_get_def_rx_moderation(u8 cq_period_mode)
76 {
77 	u8 profile_ix = cq_period_mode == DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
78 			NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;
79 
80 	return net_dim_get_rx_moderation(cq_period_mode, profile_ix);
81 }
82 EXPORT_SYMBOL(net_dim_get_def_rx_moderation);
83 
84 struct dim_cq_moder
net_dim_get_tx_moderation(u8 cq_period_mode,int ix)85 net_dim_get_tx_moderation(u8 cq_period_mode, int ix)
86 {
87 	struct dim_cq_moder cq_moder = tx_profile[cq_period_mode][ix];
88 
89 	cq_moder.cq_period_mode = cq_period_mode;
90 	return cq_moder;
91 }
92 EXPORT_SYMBOL(net_dim_get_tx_moderation);
93 
94 struct dim_cq_moder
net_dim_get_def_tx_moderation(u8 cq_period_mode)95 net_dim_get_def_tx_moderation(u8 cq_period_mode)
96 {
97 	u8 profile_ix = cq_period_mode == DIM_CQ_PERIOD_MODE_START_FROM_CQE ?
98 			NET_DIM_DEF_PROFILE_CQE : NET_DIM_DEF_PROFILE_EQE;
99 
100 	return net_dim_get_tx_moderation(cq_period_mode, profile_ix);
101 }
102 EXPORT_SYMBOL(net_dim_get_def_tx_moderation);
103 
net_dim_step(struct dim * dim)104 static int net_dim_step(struct dim *dim)
105 {
106 	if (dim->tired == (NET_DIM_PARAMS_NUM_PROFILES * 2))
107 		return DIM_TOO_TIRED;
108 
109 	switch (dim->tune_state) {
110 	case DIM_PARKING_ON_TOP:
111 	case DIM_PARKING_TIRED:
112 		break;
113 	case DIM_GOING_RIGHT:
114 		if (dim->profile_ix == (NET_DIM_PARAMS_NUM_PROFILES - 1))
115 			return DIM_ON_EDGE;
116 		dim->profile_ix++;
117 		dim->steps_right++;
118 		break;
119 	case DIM_GOING_LEFT:
120 		if (dim->profile_ix == 0)
121 			return DIM_ON_EDGE;
122 		dim->profile_ix--;
123 		dim->steps_left++;
124 		break;
125 	}
126 
127 	dim->tired++;
128 	return DIM_STEPPED;
129 }
130 
net_dim_exit_parking(struct dim * dim)131 static void net_dim_exit_parking(struct dim *dim)
132 {
133 	dim->tune_state = dim->profile_ix ? DIM_GOING_LEFT : DIM_GOING_RIGHT;
134 	net_dim_step(dim);
135 }
136 
net_dim_stats_compare(struct dim_stats * curr,struct dim_stats * prev)137 static int net_dim_stats_compare(struct dim_stats *curr,
138 				 struct dim_stats *prev)
139 {
140 	if (!prev->bpms)
141 		return curr->bpms ? DIM_STATS_BETTER : DIM_STATS_SAME;
142 
143 	if (IS_SIGNIFICANT_DIFF(curr->bpms, prev->bpms))
144 		return (curr->bpms > prev->bpms) ? DIM_STATS_BETTER :
145 						   DIM_STATS_WORSE;
146 
147 	if (!prev->ppms)
148 		return curr->ppms ? DIM_STATS_BETTER :
149 				    DIM_STATS_SAME;
150 
151 	if (IS_SIGNIFICANT_DIFF(curr->ppms, prev->ppms))
152 		return (curr->ppms > prev->ppms) ? DIM_STATS_BETTER :
153 						   DIM_STATS_WORSE;
154 
155 	if (!prev->epms)
156 		return DIM_STATS_SAME;
157 
158 	if (IS_SIGNIFICANT_DIFF(curr->epms, prev->epms))
159 		return (curr->epms < prev->epms) ? DIM_STATS_BETTER :
160 						   DIM_STATS_WORSE;
161 
162 	return DIM_STATS_SAME;
163 }
164 
net_dim_decision(struct dim_stats * curr_stats,struct dim * dim)165 static bool net_dim_decision(struct dim_stats *curr_stats, struct dim *dim)
166 {
167 	int prev_state = dim->tune_state;
168 	int prev_ix = dim->profile_ix;
169 	int stats_res;
170 	int step_res;
171 
172 	switch (dim->tune_state) {
173 	case DIM_PARKING_ON_TOP:
174 		stats_res = net_dim_stats_compare(curr_stats,
175 						  &dim->prev_stats);
176 		if (stats_res != DIM_STATS_SAME)
177 			net_dim_exit_parking(dim);
178 		break;
179 
180 	case DIM_PARKING_TIRED:
181 		dim->tired--;
182 		if (!dim->tired)
183 			net_dim_exit_parking(dim);
184 		break;
185 
186 	case DIM_GOING_RIGHT:
187 	case DIM_GOING_LEFT:
188 		stats_res = net_dim_stats_compare(curr_stats,
189 						  &dim->prev_stats);
190 		if (stats_res != DIM_STATS_BETTER)
191 			dim_turn(dim);
192 
193 		if (dim_on_top(dim)) {
194 			dim_park_on_top(dim);
195 			break;
196 		}
197 
198 		step_res = net_dim_step(dim);
199 		switch (step_res) {
200 		case DIM_ON_EDGE:
201 			dim_park_on_top(dim);
202 			break;
203 		case DIM_TOO_TIRED:
204 			dim_park_tired(dim);
205 			break;
206 		}
207 
208 		break;
209 	}
210 
211 	if (prev_state != DIM_PARKING_ON_TOP ||
212 	    dim->tune_state != DIM_PARKING_ON_TOP)
213 		dim->prev_stats = *curr_stats;
214 
215 	return dim->profile_ix != prev_ix;
216 }
217 
net_dim(struct dim * dim,struct dim_sample end_sample)218 void net_dim(struct dim *dim, struct dim_sample end_sample)
219 {
220 	struct dim_stats curr_stats;
221 	u16 nevents;
222 
223 	switch (dim->state) {
224 	case DIM_MEASURE_IN_PROGRESS:
225 		nevents = BIT_GAP(BITS_PER_TYPE(u16),
226 				  end_sample.event_ctr,
227 				  dim->start_sample.event_ctr);
228 		if (nevents < DIM_NEVENTS)
229 			break;
230 		if (!dim_calc_stats(&dim->start_sample, &end_sample, &curr_stats))
231 			break;
232 		if (net_dim_decision(&curr_stats, dim)) {
233 			dim->state = DIM_APPLY_NEW_PROFILE;
234 			schedule_work(&dim->work);
235 			break;
236 		}
237 		fallthrough;
238 	case DIM_START_MEASURE:
239 		dim_update_sample(end_sample.event_ctr, end_sample.pkt_ctr,
240 				  end_sample.byte_ctr, &dim->start_sample);
241 		dim->state = DIM_MEASURE_IN_PROGRESS;
242 		break;
243 	case DIM_APPLY_NEW_PROFILE:
244 		break;
245 	}
246 }
247 EXPORT_SYMBOL(net_dim);
248