1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include <stdint.h>
4 #include "resctrl.h"
5 
6 struct read_format {
7 	__u64 nr;			/* The number of events */
8 	struct {
9 		__u64 value;		/* The value of the event */
10 	} values[2];
11 };
12 
13 static struct perf_event_attr pea_llc_miss;
14 static struct read_format rf_cqm;
15 static int fd_lm;
16 char llc_occup_path[1024];
17 
18 static void initialize_perf_event_attr(void)
19 {
20 	pea_llc_miss.type = PERF_TYPE_HARDWARE;
21 	pea_llc_miss.size = sizeof(struct perf_event_attr);
22 	pea_llc_miss.read_format = PERF_FORMAT_GROUP;
23 	pea_llc_miss.exclude_kernel = 1;
24 	pea_llc_miss.exclude_hv = 1;
25 	pea_llc_miss.exclude_idle = 1;
26 	pea_llc_miss.exclude_callchain_kernel = 1;
27 	pea_llc_miss.inherit = 1;
28 	pea_llc_miss.exclude_guest = 1;
29 	pea_llc_miss.disabled = 1;
30 }
31 
32 static void ioctl_perf_event_ioc_reset_enable(void)
33 {
34 	ioctl(fd_lm, PERF_EVENT_IOC_RESET, 0);
35 	ioctl(fd_lm, PERF_EVENT_IOC_ENABLE, 0);
36 }
37 
38 static int perf_event_open_llc_miss(pid_t pid, int cpu_no)
39 {
40 	fd_lm = perf_event_open(&pea_llc_miss, pid, cpu_no, -1,
41 				PERF_FLAG_FD_CLOEXEC);
42 	if (fd_lm == -1) {
43 		perror("Error opening leader");
44 		ctrlc_handler(0, NULL, NULL);
45 		return -1;
46 	}
47 
48 	return 0;
49 }
50 
51 static void initialize_llc_perf(void)
52 {
53 	memset(&pea_llc_miss, 0, sizeof(struct perf_event_attr));
54 	memset(&rf_cqm, 0, sizeof(struct read_format));
55 
56 	/* Initialize perf_event_attr structures for HW_CACHE_MISSES */
57 	initialize_perf_event_attr();
58 
59 	pea_llc_miss.config = PERF_COUNT_HW_CACHE_MISSES;
60 
61 	rf_cqm.nr = 1;
62 }
63 
64 static int reset_enable_llc_perf(pid_t pid, int cpu_no)
65 {
66 	int ret = 0;
67 
68 	ret = perf_event_open_llc_miss(pid, cpu_no);
69 	if (ret < 0)
70 		return ret;
71 
72 	/* Start counters to log values */
73 	ioctl_perf_event_ioc_reset_enable();
74 
75 	return 0;
76 }
77 
78 /*
79  * get_llc_perf:	llc cache miss through perf events
80  * @llc_perf_miss:	LLC miss counter that is filled on success
81  *
82  * Perf events like HW_CACHE_MISSES could be used to validate number of
83  * cache lines allocated.
84  *
85  * Return: =0 on success.  <0 on failure.
86  */
87 static int get_llc_perf(unsigned long *llc_perf_miss)
88 {
89 	__u64 total_misses;
90 	int ret;
91 
92 	/* Stop counters after one span to get miss rate */
93 
94 	ioctl(fd_lm, PERF_EVENT_IOC_DISABLE, 0);
95 
96 	ret = read(fd_lm, &rf_cqm, sizeof(struct read_format));
97 	if (ret == -1) {
98 		perror("Could not get llc misses through perf");
99 		return -1;
100 	}
101 
102 	total_misses = rf_cqm.values[0].value;
103 	*llc_perf_miss = total_misses;
104 
105 	return 0;
106 }
107 
108 /*
109  * Get LLC Occupancy as reported by RESCTRL FS
110  * For CMT,
111  * 1. If con_mon grp and mon grp given, then read from mon grp in
112  * con_mon grp
113  * 2. If only con_mon grp given, then read from con_mon grp
114  * 3. If both not given, then read from root con_mon grp
115  * For CAT,
116  * 1. If con_mon grp given, then read from it
117  * 2. If con_mon grp not given, then read from root con_mon grp
118  *
119  * Return: =0 on success.  <0 on failure.
120  */
121 static int get_llc_occu_resctrl(unsigned long *llc_occupancy)
122 {
123 	FILE *fp;
124 
125 	fp = fopen(llc_occup_path, "r");
126 	if (!fp) {
127 		perror("Failed to open results file");
128 
129 		return errno;
130 	}
131 	if (fscanf(fp, "%lu", llc_occupancy) <= 0) {
132 		perror("Could not get llc occupancy");
133 		fclose(fp);
134 
135 		return -1;
136 	}
137 	fclose(fp);
138 
139 	return 0;
140 }
141 
142 /*
143  * print_results_cache:	the cache results are stored in a file
144  * @filename:		file that stores the results
145  * @bm_pid:		child pid that runs benchmark
146  * @llc_value:		perf miss value /
147  *			llc occupancy value reported by resctrl FS
148  *
149  * Return:		0 on success. non-zero on failure.
150  */
151 static int print_results_cache(char *filename, int bm_pid,
152 			       unsigned long llc_value)
153 {
154 	FILE *fp;
155 
156 	if (strcmp(filename, "stdio") == 0 || strcmp(filename, "stderr") == 0) {
157 		printf("Pid: %d \t LLC_value: %lu\n", bm_pid,
158 		       llc_value);
159 	} else {
160 		fp = fopen(filename, "a");
161 		if (!fp) {
162 			perror("Cannot open results file");
163 
164 			return errno;
165 		}
166 		fprintf(fp, "Pid: %d \t llc_value: %lu\n", bm_pid, llc_value);
167 		fclose(fp);
168 	}
169 
170 	return 0;
171 }
172 
173 int measure_cache_vals(struct resctrl_val_param *param, int bm_pid)
174 {
175 	unsigned long llc_perf_miss = 0, llc_occu_resc = 0, llc_value = 0;
176 	int ret;
177 
178 	/*
179 	 * Measure cache miss from perf.
180 	 */
181 	if (!strncmp(param->resctrl_val, CAT_STR, sizeof(CAT_STR))) {
182 		ret = get_llc_perf(&llc_perf_miss);
183 		if (ret < 0)
184 			return ret;
185 		llc_value = llc_perf_miss;
186 	}
187 
188 	/*
189 	 * Measure llc occupancy from resctrl.
190 	 */
191 	if (!strncmp(param->resctrl_val, CMT_STR, sizeof(CMT_STR))) {
192 		ret = get_llc_occu_resctrl(&llc_occu_resc);
193 		if (ret < 0)
194 			return ret;
195 		llc_value = llc_occu_resc;
196 	}
197 	ret = print_results_cache(param->filename, bm_pid, llc_value);
198 	if (ret)
199 		return ret;
200 
201 	return 0;
202 }
203 
204 /*
205  * cache_val:		execute benchmark and measure LLC occupancy resctrl
206  * and perf cache miss for the benchmark
207  * @param:		parameters passed to cache_val()
208  *
209  * Return:		0 on success. non-zero on failure.
210  */
211 int cat_val(struct resctrl_val_param *param)
212 {
213 	int memflush = 1, operation = 0, ret = 0;
214 	char *resctrl_val = param->resctrl_val;
215 	pid_t bm_pid;
216 
217 	if (strcmp(param->filename, "") == 0)
218 		sprintf(param->filename, "stdio");
219 
220 	bm_pid = getpid();
221 
222 	/* Taskset benchmark to specified cpu */
223 	ret = taskset_benchmark(bm_pid, param->cpu_no);
224 	if (ret)
225 		return ret;
226 
227 	/* Write benchmark to specified con_mon grp, mon_grp in resctrl FS*/
228 	ret = write_bm_pid_to_resctrl(bm_pid, param->ctrlgrp, param->mongrp,
229 				      resctrl_val);
230 	if (ret)
231 		return ret;
232 
233 	initialize_llc_perf();
234 
235 	/* Test runs until the callback setup() tells the test to stop. */
236 	while (1) {
237 		ret = param->setup(param);
238 		if (ret == END_OF_TESTS) {
239 			ret = 0;
240 			break;
241 		}
242 		if (ret < 0)
243 			break;
244 		ret = reset_enable_llc_perf(bm_pid, param->cpu_no);
245 		if (ret)
246 			break;
247 
248 		if (run_fill_buf(param->span, memflush, operation, true)) {
249 			fprintf(stderr, "Error-running fill buffer\n");
250 			ret = -1;
251 			goto pe_close;
252 		}
253 
254 		sleep(1);
255 		ret = measure_cache_vals(param, bm_pid);
256 		if (ret)
257 			goto pe_close;
258 	}
259 
260 	return ret;
261 
262 pe_close:
263 	close(fd_lm);
264 	return ret;
265 }
266 
267 /*
268  * show_cache_info:	show cache test result information
269  * @sum_llc_val:	sum of LLC cache result data
270  * @no_of_bits:		number of bits
271  * @cache_span:		cache span in bytes for CMT or in lines for CAT
272  * @max_diff:		max difference
273  * @max_diff_percent:	max difference percentage
274  * @num_of_runs:	number of runs
275  * @platform:		show test information on this platform
276  * @cmt:		CMT test or CAT test
277  *
278  * Return:		0 on success. non-zero on failure.
279  */
280 int show_cache_info(unsigned long sum_llc_val, int no_of_bits,
281 		    size_t cache_span, unsigned long max_diff,
282 		    unsigned long max_diff_percent, unsigned long num_of_runs,
283 		    bool platform, bool cmt)
284 {
285 	unsigned long avg_llc_val = 0;
286 	float diff_percent;
287 	long avg_diff = 0;
288 	int ret;
289 
290 	avg_llc_val = sum_llc_val / num_of_runs;
291 	avg_diff = (long)abs(cache_span - avg_llc_val);
292 	diff_percent = ((float)cache_span - avg_llc_val) / cache_span * 100;
293 
294 	ret = platform && abs((int)diff_percent) > max_diff_percent &&
295 	      (cmt ? (abs(avg_diff) > max_diff) : true);
296 
297 	ksft_print_msg("%s Check cache miss rate within %d%%\n",
298 		       ret ? "Fail:" : "Pass:", max_diff_percent);
299 
300 	ksft_print_msg("Percent diff=%d\n", abs((int)diff_percent));
301 	ksft_print_msg("Number of bits: %d\n", no_of_bits);
302 	ksft_print_msg("Average LLC val: %lu\n", avg_llc_val);
303 	ksft_print_msg("Cache span (%s): %zu\n", cmt ? "bytes" : "lines",
304 		       cache_span);
305 
306 	return ret;
307 }
308