tools/testing/selftests/resctrl/cache.c

   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 int 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         return 0;
  64 }
  65
  66 static int reset_enable_llc_perf(pid_t pid, int cpu_no)
  67 {
  68         int ret = 0;
  69
  70         ret = perf_event_open_llc_miss(pid, cpu_no);
  71         if (ret < 0)
  72                 return ret;
  73
  74         /* Start counters to log values */
  75         ioctl_perf_event_ioc_reset_enable();
  76
  77         return 0;
  78 }
  79
  80 /*
  81  * get_llc_perf:        llc cache miss through perf events
  82  * @cpu_no:             CPU number that the benchmark PID is binded to
  83  *
  84  * Perf events like HW_CACHE_MISSES could be used to validate number of
  85  * cache lines allocated.
  86  *
  87  * Return: =0 on success.  <0 on failure.
  88  */
  89 static int get_llc_perf(unsigned long *llc_perf_miss)
  90 {
  91         __u64 total_misses;
  92
  93         /* Stop counters after one span to get miss rate */
  94
  95         ioctl(fd_lm, PERF_EVENT_IOC_DISABLE, 0);
  96
  97         if (read(fd_lm, &rf_cqm, sizeof(struct read_format)) == -1) {
  98                 perror("Could not get llc misses through perf");
  99
 100                 return -1;
 101         }
 102
 103         total_misses = rf_cqm.values[0].value;
 104
 105         close(fd_lm);
 106
 107         *llc_perf_miss = total_misses;
 108
 109         return 0;
 110 }
 111
 112 /*
 113  * Get LLC Occupancy as reported by RESCTRL FS
 114  * For CQM,
 115  * 1. If con_mon grp and mon grp given, then read from mon grp in
 116  * con_mon grp
 117  * 2. If only con_mon grp given, then read from con_mon grp
 118  * 3. If both not given, then read from root con_mon grp
 119  * For CAT,
 120  * 1. If con_mon grp given, then read from it
 121  * 2. If con_mon grp not given, then read from root con_mon grp
 122  *
 123  * Return: =0 on success.  <0 on failure.
 124  */
 125 static int get_llc_occu_resctrl(unsigned long *llc_occupancy)
 126 {
 127         FILE *fp;
 128
 129         fp = fopen(llc_occup_path, "r");
 130         if (!fp) {
 131                 perror("Failed to open results file");
 132
 133                 return errno;
 134         }
 135         if (fscanf(fp, "%lu", llc_occupancy) <= 0) {
 136                 perror("Could not get llc occupancy");
 137                 fclose(fp);
 138
 139                 return -1;
 140         }
 141         fclose(fp);
 142
 143         return 0;
 144 }
 145
 146 /*
 147  * print_results_cache: the cache results are stored in a file
 148  * @filename:           file that stores the results
 149  * @bm_pid:             child pid that runs benchmark
 150  * @llc_value:          perf miss value /
 151  *                      llc occupancy value reported by resctrl FS
 152  *
 153  * Return:              0 on success. non-zero on failure.
 154  */
 155 static int print_results_cache(char *filename, int bm_pid,
 156                                unsigned long llc_value)
 157 {
 158         FILE *fp;
 159
 160         if (strcmp(filename, "stdio") == 0 || strcmp(filename, "stderr") == 0) {
 161                 printf("Pid: %d \t LLC_value: %lu\n", bm_pid,
 162                        llc_value);
 163         } else {
 164                 fp = fopen(filename, "a");
 165                 if (!fp) {
 166                         perror("Cannot open results file");
 167
 168                         return errno;
 169                 }
 170                 fprintf(fp, "Pid: %d \t llc_value: %lu\n", bm_pid, llc_value);
 171                 fclose(fp);
 172         }
 173
 174         return 0;
 175 }
 176
 177 int measure_cache_vals(struct resctrl_val_param *param, int bm_pid)
 178 {
 179         unsigned long llc_perf_miss = 0, llc_occu_resc = 0, llc_value = 0;
 180         int ret;
 181
 182         /*
 183          * Measure cache miss from perf.
 184          */
 185         if (!strcmp(param->resctrl_val, "cat")) {
 186                 ret = get_llc_perf(&llc_perf_miss);
 187                 if (ret < 0)
 188                         return ret;
 189                 llc_value = llc_perf_miss;
 190         }
 191
 192         /*
 193          * Measure llc occupancy from resctrl.
 194          */
 195         if (!strcmp(param->resctrl_val, "cqm")) {
 196                 ret = get_llc_occu_resctrl(&llc_occu_resc);
 197                 if (ret < 0)
 198                         return ret;
 199                 llc_value = llc_occu_resc;
 200         }
 201         ret = print_results_cache(param->filename, bm_pid, llc_value);
 202         if (ret)
 203                 return ret;
 204
 205         return 0;
 206 }
 207
 208 /*
 209  * cache_val:           execute benchmark and measure LLC occupancy resctrl
 210  * and perf cache miss for the benchmark
 211  * @param:              parameters passed to cache_val()
 212  *
 213  * Return:              0 on success. non-zero on failure.
 214  */
 215 int cat_val(struct resctrl_val_param *param)
 216 {
 217         int malloc_and_init_memory = 1, memflush = 1, operation = 0, ret = 0;
 218         char *resctrl_val = param->resctrl_val;
 219         pid_t bm_pid;
 220
 221         if (strcmp(param->filename, "") == 0)
 222                 sprintf(param->filename, "stdio");
 223
 224         bm_pid = getpid();
 225
 226         /* Taskset benchmark to specified cpu */
 227         ret = taskset_benchmark(bm_pid, param->cpu_no);
 228         if (ret)
 229                 return ret;
 230
 231         /* Write benchmark to specified con_mon grp, mon_grp in resctrl FS*/
 232         ret = write_bm_pid_to_resctrl(bm_pid, param->ctrlgrp, param->mongrp,
 233                                       resctrl_val);
 234         if (ret)
 235                 return ret;
 236
 237         if ((strcmp(resctrl_val, "cat") == 0)) {
 238                 ret = initialize_llc_perf();
 239                 if (ret)
 240                         return ret;
 241         }
 242
 243         /* Test runs until the callback setup() tells the test to stop. */
 244         while (1) {
 245                 if (strcmp(resctrl_val, "cat") == 0) {
 246                         ret = param->setup(1, param);
 247                         if (ret) {
 248                                 ret = 0;
 249                                 break;
 250                         }
 251                         ret = reset_enable_llc_perf(bm_pid, param->cpu_no);
 252                         if (ret)
 253                                 break;
 254
 255                         if (run_fill_buf(param->span, malloc_and_init_memory,
 256                                          memflush, operation, resctrl_val)) {
 257                                 fprintf(stderr, "Error-running fill buffer\n");
 258                                 ret = -1;
 259                                 break;
 260                         }
 261
 262                         sleep(1);
 263                         ret = measure_cache_vals(param, bm_pid);
 264                         if (ret)
 265                                 break;
 266                 } else {
 267                         break;
 268                 }
 269         }
 270
 271         return ret;
 272 }