1 /* 2 * (C) 2010,2011 Thomas Renninger <trenn@suse.de>, Novell Inc. 3 * 4 * Licensed under the terms of the GNU GPL License version 2. 5 */ 6 7 #if defined(__i386__) || defined(__x86_64__) 8 9 #include <stdio.h> 10 #include <stdint.h> 11 #include <stdlib.h> 12 #include <string.h> 13 #include <limits.h> 14 15 #include <cpufreq.h> 16 17 #include "helpers/helpers.h" 18 #include "idle_monitor/cpupower-monitor.h" 19 20 #define MSR_APERF 0xE8 21 #define MSR_MPERF 0xE7 22 23 #define MSR_TSC 0x10 24 25 #define MSR_AMD_HWCR 0xc0010015 26 27 enum mperf_id { C0 = 0, Cx, AVG_FREQ, MPERF_CSTATE_COUNT }; 28 29 static int mperf_get_count_percent(unsigned int self_id, double *percent, 30 unsigned int cpu); 31 static int mperf_get_count_freq(unsigned int id, unsigned long long *count, 32 unsigned int cpu); 33 static struct timespec time_start, time_end; 34 35 static cstate_t mperf_cstates[MPERF_CSTATE_COUNT] = { 36 { 37 .name = "C0", 38 .desc = N_("Processor Core not idle"), 39 .id = C0, 40 .range = RANGE_THREAD, 41 .get_count_percent = mperf_get_count_percent, 42 }, 43 { 44 .name = "Cx", 45 .desc = N_("Processor Core in an idle state"), 46 .id = Cx, 47 .range = RANGE_THREAD, 48 .get_count_percent = mperf_get_count_percent, 49 }, 50 51 { 52 .name = "Freq", 53 .desc = N_("Average Frequency (including boost) in MHz"), 54 .id = AVG_FREQ, 55 .range = RANGE_THREAD, 56 .get_count = mperf_get_count_freq, 57 }, 58 }; 59 60 enum MAX_FREQ_MODE { MAX_FREQ_SYSFS, MAX_FREQ_TSC_REF }; 61 static int max_freq_mode; 62 /* 63 * The max frequency mperf is ticking at (in C0), either retrieved via: 64 * 1) calculated after measurements if we know TSC ticks at mperf/P0 frequency 65 * 2) cpufreq /sys/devices/.../cpu0/cpufreq/cpuinfo_max_freq at init time 66 * 1. Is preferred as it also works without cpufreq subsystem (e.g. on Xen) 67 */ 68 static unsigned long max_frequency; 69 70 static unsigned long long tsc_at_measure_start; 71 static unsigned long long tsc_at_measure_end; 72 static unsigned long long *mperf_previous_count; 73 static unsigned long long *aperf_previous_count; 74 static unsigned long long *mperf_current_count; 75 static unsigned long long *aperf_current_count; 76 77 /* valid flag for all CPUs. If a MSR read failed it will be zero */ 78 static int *is_valid; 79 80 static int mperf_get_tsc(unsigned long long *tsc) 81 { 82 int ret; 83 ret = read_msr(0, MSR_TSC, tsc); 84 if (ret) 85 dprint("Reading TSC MSR failed, returning %llu\n", *tsc); 86 return ret; 87 } 88 89 static int mperf_init_stats(unsigned int cpu) 90 { 91 unsigned long long val; 92 int ret; 93 94 ret = read_msr(cpu, MSR_APERF, &val); 95 aperf_previous_count[cpu] = val; 96 ret |= read_msr(cpu, MSR_MPERF, &val); 97 mperf_previous_count[cpu] = val; 98 is_valid[cpu] = !ret; 99 100 return 0; 101 } 102 103 static int mperf_measure_stats(unsigned int cpu) 104 { 105 unsigned long long val; 106 int ret; 107 108 ret = read_msr(cpu, MSR_APERF, &val); 109 aperf_current_count[cpu] = val; 110 ret |= read_msr(cpu, MSR_MPERF, &val); 111 mperf_current_count[cpu] = val; 112 is_valid[cpu] = !ret; 113 114 return 0; 115 } 116 117 static int mperf_get_count_percent(unsigned int id, double *percent, 118 unsigned int cpu) 119 { 120 unsigned long long aperf_diff, mperf_diff, tsc_diff; 121 unsigned long long timediff; 122 123 if (!is_valid[cpu]) 124 return -1; 125 126 if (id != C0 && id != Cx) 127 return -1; 128 129 mperf_diff = mperf_current_count[cpu] - mperf_previous_count[cpu]; 130 aperf_diff = aperf_current_count[cpu] - aperf_previous_count[cpu]; 131 132 if (max_freq_mode == MAX_FREQ_TSC_REF) { 133 tsc_diff = tsc_at_measure_end - tsc_at_measure_start; 134 *percent = 100.0 * mperf_diff / tsc_diff; 135 dprint("%s: TSC Ref - mperf_diff: %llu, tsc_diff: %llu\n", 136 mperf_cstates[id].name, mperf_diff, tsc_diff); 137 } else if (max_freq_mode == MAX_FREQ_SYSFS) { 138 timediff = timespec_diff_us(time_start, time_end); 139 *percent = 100.0 * mperf_diff / timediff; 140 dprint("%s: MAXFREQ - mperf_diff: %llu, time_diff: %llu\n", 141 mperf_cstates[id].name, mperf_diff, timediff); 142 } else 143 return -1; 144 145 if (id == Cx) 146 *percent = 100.0 - *percent; 147 148 dprint("%s: previous: %llu - current: %llu - (%u)\n", 149 mperf_cstates[id].name, mperf_diff, aperf_diff, cpu); 150 dprint("%s: %f\n", mperf_cstates[id].name, *percent); 151 return 0; 152 } 153 154 static int mperf_get_count_freq(unsigned int id, unsigned long long *count, 155 unsigned int cpu) 156 { 157 unsigned long long aperf_diff, mperf_diff, time_diff, tsc_diff; 158 159 if (id != AVG_FREQ) 160 return 1; 161 162 if (!is_valid[cpu]) 163 return -1; 164 165 mperf_diff = mperf_current_count[cpu] - mperf_previous_count[cpu]; 166 aperf_diff = aperf_current_count[cpu] - aperf_previous_count[cpu]; 167 168 if (max_freq_mode == MAX_FREQ_TSC_REF) { 169 /* Calculate max_freq from TSC count */ 170 tsc_diff = tsc_at_measure_end - tsc_at_measure_start; 171 time_diff = timespec_diff_us(time_start, time_end); 172 max_frequency = tsc_diff / time_diff; 173 } 174 175 *count = max_frequency * ((double)aperf_diff / mperf_diff); 176 dprint("%s: Average freq based on %s maximum frequency:\n", 177 mperf_cstates[id].name, 178 (max_freq_mode == MAX_FREQ_TSC_REF) ? "TSC calculated" : "sysfs read"); 179 dprint("%max_frequency: %lu", max_frequency); 180 dprint("aperf_diff: %llu\n", aperf_diff); 181 dprint("mperf_diff: %llu\n", mperf_diff); 182 dprint("avg freq: %llu\n", *count); 183 return 0; 184 } 185 186 static int mperf_start(void) 187 { 188 int cpu; 189 unsigned long long dbg; 190 191 clock_gettime(CLOCK_REALTIME, &time_start); 192 mperf_get_tsc(&tsc_at_measure_start); 193 194 for (cpu = 0; cpu < cpu_count; cpu++) 195 mperf_init_stats(cpu); 196 197 mperf_get_tsc(&dbg); 198 dprint("TSC diff: %llu\n", dbg - tsc_at_measure_start); 199 return 0; 200 } 201 202 static int mperf_stop(void) 203 { 204 unsigned long long dbg; 205 int cpu; 206 207 for (cpu = 0; cpu < cpu_count; cpu++) 208 mperf_measure_stats(cpu); 209 210 mperf_get_tsc(&tsc_at_measure_end); 211 clock_gettime(CLOCK_REALTIME, &time_end); 212 213 mperf_get_tsc(&dbg); 214 dprint("TSC diff: %llu\n", dbg - tsc_at_measure_end); 215 216 return 0; 217 } 218 219 /* 220 * Mperf register is defined to tick at P0 (maximum) frequency 221 * 222 * Instead of reading out P0 which can be tricky to read out from HW, 223 * we use TSC counter if it reliably ticks at P0/mperf frequency. 224 * 225 * Still try to fall back to: 226 * /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq 227 * on older Intel HW without invariant TSC feature. 228 * Or on AMD machines where TSC does not tick at P0 (do not exist yet, but 229 * it's still double checked (MSR_AMD_HWCR)). 230 * 231 * On these machines the user would still get useful mperf 232 * stats when acpi-cpufreq driver is loaded. 233 */ 234 static int init_maxfreq_mode(void) 235 { 236 int ret; 237 unsigned long long hwcr; 238 unsigned long min; 239 240 if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_INV_TSC)) 241 goto use_sysfs; 242 243 if (cpupower_cpu_info.vendor == X86_VENDOR_AMD) { 244 /* MSR_AMD_HWCR tells us whether TSC runs at P0/mperf 245 * freq. 246 * A test whether hwcr is accessable/available would be: 247 * (cpupower_cpu_info.family > 0x10 || 248 * cpupower_cpu_info.family == 0x10 && 249 * cpupower_cpu_info.model >= 0x2)) 250 * This should be the case for all aperf/mperf 251 * capable AMD machines and is therefore safe to test here. 252 * Compare with Linus kernel git commit: acf01734b1747b1ec4 253 */ 254 ret = read_msr(0, MSR_AMD_HWCR, &hwcr); 255 /* 256 * If the MSR read failed, assume a Xen system that did 257 * not explicitly provide access to it and assume TSC works 258 */ 259 if (ret != 0) { 260 dprint("TSC read 0x%x failed - assume TSC working\n", 261 MSR_AMD_HWCR); 262 return 0; 263 } else if (1 & (hwcr >> 24)) { 264 max_freq_mode = MAX_FREQ_TSC_REF; 265 return 0; 266 } else { /* Use sysfs max frequency if available */ } 267 } else if (cpupower_cpu_info.vendor == X86_VENDOR_INTEL) { 268 /* 269 * On Intel we assume mperf (in C0) is ticking at same 270 * rate than TSC 271 */ 272 max_freq_mode = MAX_FREQ_TSC_REF; 273 return 0; 274 } 275 use_sysfs: 276 if (cpufreq_get_hardware_limits(0, &min, &max_frequency)) { 277 dprint("Cannot retrieve max freq from cpufreq kernel " 278 "subsystem\n"); 279 return -1; 280 } 281 max_freq_mode = MAX_FREQ_SYSFS; 282 return 0; 283 } 284 285 /* 286 * This monitor provides: 287 * 288 * 1) Average frequency a CPU resided in 289 * This always works if the CPU has aperf/mperf capabilities 290 * 291 * 2) C0 and Cx (any sleep state) time a CPU resided in 292 * Works if mperf timer stops ticking in sleep states which 293 * seem to be the case on all current HW. 294 * Both is directly retrieved from HW registers and is independent 295 * from kernel statistics. 296 */ 297 struct cpuidle_monitor mperf_monitor; 298 struct cpuidle_monitor *mperf_register(void) 299 { 300 if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_APERF)) 301 return NULL; 302 303 if (init_maxfreq_mode()) 304 return NULL; 305 306 /* Free this at program termination */ 307 is_valid = calloc(cpu_count, sizeof(int)); 308 mperf_previous_count = calloc(cpu_count, sizeof(unsigned long long)); 309 aperf_previous_count = calloc(cpu_count, sizeof(unsigned long long)); 310 mperf_current_count = calloc(cpu_count, sizeof(unsigned long long)); 311 aperf_current_count = calloc(cpu_count, sizeof(unsigned long long)); 312 313 mperf_monitor.name_len = strlen(mperf_monitor.name); 314 return &mperf_monitor; 315 } 316 317 void mperf_unregister(void) 318 { 319 free(mperf_previous_count); 320 free(aperf_previous_count); 321 free(mperf_current_count); 322 free(aperf_current_count); 323 free(is_valid); 324 } 325 326 struct cpuidle_monitor mperf_monitor = { 327 .name = "Mperf", 328 .hw_states_num = MPERF_CSTATE_COUNT, 329 .hw_states = mperf_cstates, 330 .start = mperf_start, 331 .stop = mperf_stop, 332 .do_register = mperf_register, 333 .unregister = mperf_unregister, 334 .needs_root = 1, 335 .overflow_s = 922000000 /* 922337203 seconds TSC overflow 336 at 20GHz */ 337 }; 338 #endif /* #if defined(__i386__) || defined(__x86_64__) */ 339