selftests/resctrl/cache.c

0001 // SPDX-License-Identifier: GPL-2.0
0002
0003 #include <stdint.h>
0004 #include "resctrl.h"
0005
0006 struct read_format {
0007     __u64 nr;           /* The number of events */
0008     struct {
0009         __u64 value;        /* The value of the event */
0010     } values[2];
0011 };
0012
0013 static struct perf_event_attr pea_llc_miss;
0014 static struct read_format rf_cqm;
0015 static int fd_lm;
0016 char llc_occup_path[1024];
0017
0018 static void initialize_perf_event_attr(void)
0019 {
0020     pea_llc_miss.type = PERF_TYPE_HARDWARE;
0021     pea_llc_miss.size = sizeof(struct perf_event_attr);
0022     pea_llc_miss.read_format = PERF_FORMAT_GROUP;
0023     pea_llc_miss.exclude_kernel = 1;
0024     pea_llc_miss.exclude_hv = 1;
0025     pea_llc_miss.exclude_idle = 1;
0026     pea_llc_miss.exclude_callchain_kernel = 1;
0027     pea_llc_miss.inherit = 1;
0028     pea_llc_miss.exclude_guest = 1;
0029     pea_llc_miss.disabled = 1;
0030 }
0031
0032 static void ioctl_perf_event_ioc_reset_enable(void)
0033 {
0034     ioctl(fd_lm, PERF_EVENT_IOC_RESET, 0);
0035     ioctl(fd_lm, PERF_EVENT_IOC_ENABLE, 0);
0036 }
0037
0038 static int perf_event_open_llc_miss(pid_t pid, int cpu_no)
0039 {
0040     fd_lm = perf_event_open(&pea_llc_miss, pid, cpu_no, -1,
0041                 PERF_FLAG_FD_CLOEXEC);
0042     if (fd_lm == -1) {
0043         perror("Error opening leader");
0044         ctrlc_handler(0, NULL, NULL);
0045         return -1;
0046     }
0047
0048     return 0;
0049 }
0050
0051 static int initialize_llc_perf(void)
0052 {
0053     memset(&pea_llc_miss, 0, sizeof(struct perf_event_attr));
0054     memset(&rf_cqm, 0, sizeof(struct read_format));
0055
0056     /* Initialize perf_event_attr structures for HW_CACHE_MISSES */
0057     initialize_perf_event_attr();
0058
0059     pea_llc_miss.config = PERF_COUNT_HW_CACHE_MISSES;
0060
0061     rf_cqm.nr = 1;
0062
0063     return 0;
0064 }
0065
0066 static int reset_enable_llc_perf(pid_t pid, int cpu_no)
0067 {
0068     int ret = 0;
0069
0070     ret = perf_event_open_llc_miss(pid, cpu_no);
0071     if (ret < 0)
0072         return ret;
0073
0074     /* Start counters to log values */
0075     ioctl_perf_event_ioc_reset_enable();
0076
0077     return 0;
0078 }
0079
0080 /*
0081  * get_llc_perf:    llc cache miss through perf events
0082  * @cpu_no:     CPU number that the benchmark PID is binded to
0083  *
0084  * Perf events like HW_CACHE_MISSES could be used to validate number of
0085  * cache lines allocated.
0086  *
0087  * Return: =0 on success.  <0 on failure.
0088  */
0089 static int get_llc_perf(unsigned long *llc_perf_miss)
0090 {
0091     __u64 total_misses;
0092
0093     /* Stop counters after one span to get miss rate */
0094
0095     ioctl(fd_lm, PERF_EVENT_IOC_DISABLE, 0);
0096
0097     if (read(fd_lm, &rf_cqm, sizeof(struct read_format)) == -1) {
0098         perror("Could not get llc misses through perf");
0099
0100         return -1;
0101     }
0102
0103     total_misses = rf_cqm.values[0].value;
0104
0105     close(fd_lm);
0106
0107     *llc_perf_miss = total_misses;
0108
0109     return 0;
0110 }
0111
0112 /*
0113  * Get LLC Occupancy as reported by RESCTRL FS
0114  * For CMT,
0115  * 1. If con_mon grp and mon grp given, then read from mon grp in
0116  * con_mon grp
0117  * 2. If only con_mon grp given, then read from con_mon grp
0118  * 3. If both not given, then read from root con_mon grp
0119  * For CAT,
0120  * 1. If con_mon grp given, then read from it
0121  * 2. If con_mon grp not given, then read from root con_mon grp
0122  *
0123  * Return: =0 on success.  <0 on failure.
0124  */
0125 static int get_llc_occu_resctrl(unsigned long *llc_occupancy)
0126 {
0127     FILE *fp;
0128
0129     fp = fopen(llc_occup_path, "r");
0130     if (!fp) {
0131         perror("Failed to open results file");
0132
0133         return errno;
0134     }
0135     if (fscanf(fp, "%lu", llc_occupancy) <= 0) {
0136         perror("Could not get llc occupancy");
0137         fclose(fp);
0138
0139         return -1;
0140     }
0141     fclose(fp);
0142
0143     return 0;
0144 }
0145
0146 /*
0147  * print_results_cache: the cache results are stored in a file
0148  * @filename:       file that stores the results
0149  * @bm_pid:     child pid that runs benchmark
0150  * @llc_value:      perf miss value /
0151  *          llc occupancy value reported by resctrl FS
0152  *
0153  * Return:      0 on success. non-zero on failure.
0154  */
0155 static int print_results_cache(char *filename, int bm_pid,
0156                    unsigned long llc_value)
0157 {
0158     FILE *fp;
0159
0160     if (strcmp(filename, "stdio") == 0 || strcmp(filename, "stderr") == 0) {
0161         printf("Pid: %d \t LLC_value: %lu\n", bm_pid,
0162                llc_value);
0163     } else {
0164         fp = fopen(filename, "a");
0165         if (!fp) {
0166             perror("Cannot open results file");
0167
0168             return errno;
0169         }
0170         fprintf(fp, "Pid: %d \t llc_value: %lu\n", bm_pid, llc_value);
0171         fclose(fp);
0172     }
0173
0174     return 0;
0175 }
0176
0177 int measure_cache_vals(struct resctrl_val_param *param, int bm_pid)
0178 {
0179     unsigned long llc_perf_miss = 0, llc_occu_resc = 0, llc_value = 0;
0180     int ret;
0181
0182     /*
0183      * Measure cache miss from perf.
0184      */
0185     if (!strncmp(param->resctrl_val, CAT_STR, sizeof(CAT_STR))) {
0186         ret = get_llc_perf(&llc_perf_miss);
0187         if (ret < 0)
0188             return ret;
0189         llc_value = llc_perf_miss;
0190     }
0191
0192     /*
0193      * Measure llc occupancy from resctrl.
0194      */
0195     if (!strncmp(param->resctrl_val, CMT_STR, sizeof(CMT_STR))) {
0196         ret = get_llc_occu_resctrl(&llc_occu_resc);
0197         if (ret < 0)
0198             return ret;
0199         llc_value = llc_occu_resc;
0200     }
0201     ret = print_results_cache(param->filename, bm_pid, llc_value);
0202     if (ret)
0203         return ret;
0204
0205     return 0;
0206 }
0207
0208 /*
0209  * cache_val:       execute benchmark and measure LLC occupancy resctrl
0210  * and perf cache miss for the benchmark
0211  * @param:      parameters passed to cache_val()
0212  *
0213  * Return:      0 on success. non-zero on failure.
0214  */
0215 int cat_val(struct resctrl_val_param *param)
0216 {
0217     int malloc_and_init_memory = 1, memflush = 1, operation = 0, ret = 0;
0218     char *resctrl_val = param->resctrl_val;
0219     pid_t bm_pid;
0220
0221     if (strcmp(param->filename, "") == 0)
0222         sprintf(param->filename, "stdio");
0223
0224     bm_pid = getpid();
0225
0226     /* Taskset benchmark to specified cpu */
0227     ret = taskset_benchmark(bm_pid, param->cpu_no);
0228     if (ret)
0229         return ret;
0230
0231     /* Write benchmark to specified con_mon grp, mon_grp in resctrl FS*/
0232     ret = write_bm_pid_to_resctrl(bm_pid, param->ctrlgrp, param->mongrp,
0233                       resctrl_val);
0234     if (ret)
0235         return ret;
0236
0237     if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR))) {
0238         ret = initialize_llc_perf();
0239         if (ret)
0240             return ret;
0241     }
0242
0243     /* Test runs until the callback setup() tells the test to stop. */
0244     while (1) {
0245         if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR))) {
0246             ret = param->setup(1, param);
0247             if (ret) {
0248                 ret = 0;
0249                 break;
0250             }
0251             ret = reset_enable_llc_perf(bm_pid, param->cpu_no);
0252             if (ret)
0253                 break;
0254
0255             if (run_fill_buf(param->span, malloc_and_init_memory,
0256                      memflush, operation, resctrl_val)) {
0257                 fprintf(stderr, "Error-running fill buffer\n");
0258                 ret = -1;
0259                 break;
0260             }
0261
0262             sleep(1);
0263             ret = measure_cache_vals(param, bm_pid);
0264             if (ret)
0265                 break;
0266         } else {
0267             break;
0268         }
0269     }
0270
0271     return ret;
0272 }
0273
0274 /*
0275  * show_cache_info: show cache test result information
0276  * @sum_llc_val:    sum of LLC cache result data
0277  * @no_of_bits:     number of bits
0278  * @cache_span:     cache span in bytes for CMT or in lines for CAT
0279  * @max_diff:       max difference
0280  * @max_diff_percent:   max difference percentage
0281  * @num_of_runs:    number of runs
0282  * @platform:       show test information on this platform
0283  * @cmt:        CMT test or CAT test
0284  *
0285  * Return:      0 on success. non-zero on failure.
0286  */
0287 int show_cache_info(unsigned long sum_llc_val, int no_of_bits,
0288             unsigned long cache_span, unsigned long max_diff,
0289             unsigned long max_diff_percent, unsigned long num_of_runs,
0290             bool platform, bool cmt)
0291 {
0292     unsigned long avg_llc_val = 0;
0293     float diff_percent;
0294     long avg_diff = 0;
0295     int ret;
0296
0297     avg_llc_val = sum_llc_val / (num_of_runs - 1);
0298     avg_diff = (long)abs(cache_span - avg_llc_val);
0299     diff_percent = ((float)cache_span - avg_llc_val) / cache_span * 100;
0300
0301     ret = platform && abs((int)diff_percent) > max_diff_percent &&
0302           (cmt ? (abs(avg_diff) > max_diff) : true);
0303
0304     ksft_print_msg("%s Check cache miss rate within %d%%\n",
0305                ret ? "Fail:" : "Pass:", max_diff_percent);
0306
0307     ksft_print_msg("Percent diff=%d\n", abs((int)diff_percent));
0308     ksft_print_msg("Number of bits: %d\n", no_of_bits);
0309     ksft_print_msg("Average LLC val: %lu\n", avg_llc_val);
0310     ksft_print_msg("Cache span (%s): %lu\n", cmt ? "bytes" : "lines",
0311                cache_span);
0312
0313     return ret;
0314 }