1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Memory Bandwidth Monitoring (MBM) test
4 *
5 * Copyright (C) 2018 Intel Corporation
6 *
7 * Authors:
8 * Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
9 * Fenghua Yu <fenghua.yu@intel.com>
10 */
11 #include "resctrl.h"
12
13 #define RESULT_FILE_NAME "result_mbm"
14 #define MAX_DIFF_PERCENT 8
15 #define NUM_OF_RUNS 5
16
17 static int
18 show_bw_info(unsigned long *bw_imc, unsigned long *bw_resc, size_t span)
19 {
20 unsigned long sum_bw_imc = 0, sum_bw_resc = 0;
21 long avg_bw_imc = 0, avg_bw_resc = 0;
22 int runs, ret, avg_diff_per;
23 float avg_diff = 0;
24
25 /*
26 * Discard the first value which is inaccurate due to monitoring setup
27 * transition phase.
28 */
29 for (runs = 1; runs < NUM_OF_RUNS ; runs++) {
30 sum_bw_imc += bw_imc[runs];
31 sum_bw_resc += bw_resc[runs];
32 }
33
34 avg_bw_imc = sum_bw_imc / 4;
35 avg_bw_resc = sum_bw_resc / 4;
36 avg_diff = (float)labs(avg_bw_resc - avg_bw_imc) / avg_bw_imc;
37 avg_diff_per = (int)(avg_diff * 100);
38
39 ret = avg_diff_per > MAX_DIFF_PERCENT;
40 ksft_print_msg("%s Check MBM diff within %d%%\n",
41 ret ? "Fail:" : "Pass:", MAX_DIFF_PERCENT);
42 ksft_print_msg("avg_diff_per: %d%%\n", avg_diff_per);
43 ksft_print_msg("Span (MB): %zu\n", span / MB);
44 ksft_print_msg("avg_bw_imc: %lu\n", avg_bw_imc);
45 ksft_print_msg("avg_bw_resc: %lu\n", avg_bw_resc);
46
47 return ret;
48 }
49
50 static int check_results(size_t span)
51 {
52 unsigned long bw_imc[NUM_OF_RUNS], bw_resc[NUM_OF_RUNS];
53 char temp[1024], *token_array[8];
54 char output[] = RESULT_FILE_NAME;
55 int runs, ret;
56 FILE *fp;
57
58 ksft_print_msg("Checking for pass/fail\n");
59
60 fp = fopen(output, "r");
61 if (!fp) {
62 ksft_perror(output);
63
64 return -1;
65 }
66
67 runs = 0;
68 while (fgets(temp, sizeof(temp), fp)) {
69 char *token = strtok(temp, ":\t");
70 int i = 0;
71
72 while (token) {
73 token_array[i++] = token;
74 token = strtok(NULL, ":\t");
75 }
76
77 bw_resc[runs] = strtoul(token_array[5], NULL, 0);
78 bw_imc[runs] = strtoul(token_array[3], NULL, 0);
79 runs++;
80 }
81
82 ret = show_bw_info(bw_imc, bw_resc, span);
83
84 fclose(fp);
85
86 return ret;
87 }
88
89 static int mbm_init(const struct resctrl_val_param *param, int domain_id)
90 {
91 int ret;
92
93 ret = initialize_mem_bw_imc();
94 if (ret)
95 return ret;
96
97 initialize_mem_bw_resctrl(param, domain_id);
98
99 return 0;
100 }
101
102 static int mbm_setup(const struct resctrl_test *test,
103 const struct user_params *uparams,
104 struct resctrl_val_param *p)
105 {
106 int ret = 0;
107
108 /* Run NUM_OF_RUNS times */
109 if (p->num_of_runs >= NUM_OF_RUNS)
110 return END_OF_TESTS;
111
112 /* Set up shemata with 100% allocation on the first run. */
113 if (p->num_of_runs == 0 && resctrl_resource_exists("MB"))
114 ret = write_schemata(p->ctrlgrp, "100", uparams->cpu, test->resource);
115
116 p->num_of_runs++;
117
118 return ret;
119 }
120
121 static int mbm_measure(const struct user_params *uparams,
122 struct resctrl_val_param *param, pid_t bm_pid)
123 {
124 return measure_mem_bw(uparams, param, bm_pid, "reads");
125 }
126
127 static void mbm_test_cleanup(void)
128 {
129 remove(RESULT_FILE_NAME);
130 }
131
132 static int mbm_run_test(const struct resctrl_test *test, const struct user_params *uparams)
133 {
134 struct resctrl_val_param param = {
135 .ctrlgrp = "c1",
136 .filename = RESULT_FILE_NAME,
137 .init = mbm_init,
138 .setup = mbm_setup,
139 .measure = mbm_measure,
140 };
141 int ret;
142
143 remove(RESULT_FILE_NAME);
144
145 ret = resctrl_val(test, uparams, uparams->benchmark_cmd, ¶m);
146 if (ret)
147 return ret;
148
149 ret = check_results(DEFAULT_SPAN);
150 if (ret && (get_vendor() == ARCH_INTEL))
151 ksft_print_msg("Intel MBM may be inaccurate when Sub-NUMA Clustering is enabled. Check BIOS configuration.\n");
152
153 return ret;
154 }
155
156 static bool mbm_feature_check(const struct resctrl_test *test)
157 {
158 return resctrl_mon_feature_exists("L3_MON", "mbm_total_bytes") &&
159 resctrl_mon_feature_exists("L3_MON", "mbm_local_bytes");
160 }
161
162 struct resctrl_test mbm_test = {
163 .name = "MBM",
164 .resource = "MB",
165 .vendor_specific = ARCH_INTEL,
166 .feature_check = mbm_feature_check,
167 .run_test = mbm_run_test,
168 .cleanup = mbm_test_cleanup,
169 };
170
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