2 * (C) 2010,2011 Thomas Renninger <trenn@suse.de>, Novell Inc.
4 * Licensed under the terms of the GNU GPL License version 2.
7 #if defined(__i386__) || defined(__x86_64__)
17 #include "helpers/helpers.h"
18 #include "idle_monitor/cpupower-monitor.h"
20 #define MSR_APERF 0xE8
21 #define MSR_MPERF 0xE7
25 #define MSR_AMD_HWCR 0xc0010015
27 enum mperf_id { C0 = 0, Cx, AVG_FREQ, MPERF_CSTATE_COUNT };
29 static int mperf_get_count_percent(unsigned int self_id, double *percent,
31 static int mperf_get_count_freq(unsigned int id, unsigned long long *count,
33 static struct timespec time_start, time_end;
35 static cstate_t mperf_cstates[MPERF_CSTATE_COUNT] = {
38 .desc = N_("Processor Core not idle"),
40 .range = RANGE_THREAD,
41 .get_count_percent = mperf_get_count_percent,
45 .desc = N_("Processor Core in an idle state"),
47 .range = RANGE_THREAD,
48 .get_count_percent = mperf_get_count_percent,
53 .desc = N_("Average Frequency (including boost) in MHz"),
55 .range = RANGE_THREAD,
56 .get_count = mperf_get_count_freq,
60 enum MAX_FREQ_MODE { MAX_FREQ_SYSFS, MAX_FREQ_TSC_REF };
61 static int max_freq_mode;
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)
68 static unsigned long max_frequency;
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;
77 /* valid flag for all CPUs. If a MSR read failed it will be zero */
80 static int mperf_get_tsc(unsigned long long *tsc)
84 ret = read_msr(base_cpu, MSR_TSC, tsc);
86 dprint("Reading TSC MSR failed, returning %llu\n", *tsc);
90 static int mperf_init_stats(unsigned int cpu)
92 unsigned long long val;
95 ret = read_msr(cpu, MSR_APERF, &val);
96 aperf_previous_count[cpu] = val;
97 ret |= read_msr(cpu, MSR_MPERF, &val);
98 mperf_previous_count[cpu] = val;
104 static int mperf_measure_stats(unsigned int cpu)
106 unsigned long long val;
109 ret = read_msr(cpu, MSR_APERF, &val);
110 aperf_current_count[cpu] = val;
111 ret |= read_msr(cpu, MSR_MPERF, &val);
112 mperf_current_count[cpu] = val;
113 is_valid[cpu] = !ret;
118 static int mperf_get_count_percent(unsigned int id, double *percent,
121 unsigned long long aperf_diff, mperf_diff, tsc_diff;
122 unsigned long long timediff;
127 if (id != C0 && id != Cx)
130 mperf_diff = mperf_current_count[cpu] - mperf_previous_count[cpu];
131 aperf_diff = aperf_current_count[cpu] - aperf_previous_count[cpu];
133 if (max_freq_mode == MAX_FREQ_TSC_REF) {
134 tsc_diff = tsc_at_measure_end[cpu] - tsc_at_measure_start[cpu];
135 *percent = 100.0 * mperf_diff / tsc_diff;
136 dprint("%s: TSC Ref - mperf_diff: %llu, tsc_diff: %llu\n",
137 mperf_cstates[id].name, mperf_diff, tsc_diff);
138 } else if (max_freq_mode == MAX_FREQ_SYSFS) {
139 timediff = max_frequency * timespec_diff_us(time_start, time_end);
140 *percent = 100.0 * mperf_diff / timediff;
141 dprint("%s: MAXFREQ - mperf_diff: %llu, time_diff: %llu\n",
142 mperf_cstates[id].name, mperf_diff, timediff);
147 *percent = 100.0 - *percent;
149 dprint("%s: previous: %llu - current: %llu - (%u)\n",
150 mperf_cstates[id].name, mperf_diff, aperf_diff, cpu);
151 dprint("%s: %f\n", mperf_cstates[id].name, *percent);
155 static int mperf_get_count_freq(unsigned int id, unsigned long long *count,
158 unsigned long long aperf_diff, mperf_diff, time_diff, tsc_diff;
166 mperf_diff = mperf_current_count[cpu] - mperf_previous_count[cpu];
167 aperf_diff = aperf_current_count[cpu] - aperf_previous_count[cpu];
169 if (max_freq_mode == MAX_FREQ_TSC_REF) {
170 /* Calculate max_freq from TSC count */
171 tsc_diff = tsc_at_measure_end[cpu] - tsc_at_measure_start[cpu];
172 time_diff = timespec_diff_us(time_start, time_end);
173 max_frequency = tsc_diff / time_diff;
176 *count = max_frequency * ((double)aperf_diff / mperf_diff);
177 dprint("%s: Average freq based on %s maximum frequency:\n",
178 mperf_cstates[id].name,
179 (max_freq_mode == MAX_FREQ_TSC_REF) ? "TSC calculated" : "sysfs read");
180 dprint("max_frequency: %lu\n", max_frequency);
181 dprint("aperf_diff: %llu\n", aperf_diff);
182 dprint("mperf_diff: %llu\n", mperf_diff);
183 dprint("avg freq: %llu\n", *count);
187 static int mperf_start(void)
191 clock_gettime(CLOCK_REALTIME, &time_start);
193 for (cpu = 0; cpu < cpu_count; cpu++) {
194 mperf_get_tsc(&tsc_at_measure_start[cpu]);
195 mperf_init_stats(cpu);
201 static int mperf_stop(void)
205 for (cpu = 0; cpu < cpu_count; cpu++) {
206 mperf_measure_stats(cpu);
207 mperf_get_tsc(&tsc_at_measure_end[cpu]);
210 clock_gettime(CLOCK_REALTIME, &time_end);
215 * Mperf register is defined to tick at P0 (maximum) frequency
217 * Instead of reading out P0 which can be tricky to read out from HW,
218 * we use TSC counter if it reliably ticks at P0/mperf frequency.
220 * Still try to fall back to:
221 * /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
222 * on older Intel HW without invariant TSC feature.
223 * Or on AMD machines where TSC does not tick at P0 (do not exist yet, but
224 * it's still double checked (MSR_AMD_HWCR)).
226 * On these machines the user would still get useful mperf
227 * stats when acpi-cpufreq driver is loaded.
229 static int init_maxfreq_mode(void)
232 unsigned long long hwcr;
235 if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_INV_TSC))
238 if (cpupower_cpu_info.vendor == X86_VENDOR_AMD) {
239 /* MSR_AMD_HWCR tells us whether TSC runs at P0/mperf
241 * A test whether hwcr is accessable/available would be:
242 * (cpupower_cpu_info.family > 0x10 ||
243 * cpupower_cpu_info.family == 0x10 &&
244 * cpupower_cpu_info.model >= 0x2))
245 * This should be the case for all aperf/mperf
246 * capable AMD machines and is therefore safe to test here.
247 * Compare with Linus kernel git commit: acf01734b1747b1ec4
249 ret = read_msr(0, MSR_AMD_HWCR, &hwcr);
251 * If the MSR read failed, assume a Xen system that did
252 * not explicitly provide access to it and assume TSC works
255 dprint("TSC read 0x%x failed - assume TSC working\n",
258 } else if (1 & (hwcr >> 24)) {
259 max_freq_mode = MAX_FREQ_TSC_REF;
261 } else { /* Use sysfs max frequency if available */ }
262 } else if (cpupower_cpu_info.vendor == X86_VENDOR_INTEL) {
264 * On Intel we assume mperf (in C0) is ticking at same
267 max_freq_mode = MAX_FREQ_TSC_REF;
271 if (cpufreq_get_hardware_limits(0, &min, &max_frequency)) {
272 dprint("Cannot retrieve max freq from cpufreq kernel "
276 max_freq_mode = MAX_FREQ_SYSFS;
277 max_frequency /= 1000; /* Default automatically to MHz value */
282 * This monitor provides:
284 * 1) Average frequency a CPU resided in
285 * This always works if the CPU has aperf/mperf capabilities
287 * 2) C0 and Cx (any sleep state) time a CPU resided in
288 * Works if mperf timer stops ticking in sleep states which
289 * seem to be the case on all current HW.
290 * Both is directly retrieved from HW registers and is independent
291 * from kernel statistics.
293 struct cpuidle_monitor mperf_monitor;
294 struct cpuidle_monitor *mperf_register(void)
296 if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_APERF))
299 if (init_maxfreq_mode())
302 /* Free this at program termination */
303 is_valid = calloc(cpu_count, sizeof(int));
304 mperf_previous_count = calloc(cpu_count, sizeof(unsigned long long));
305 aperf_previous_count = calloc(cpu_count, sizeof(unsigned long long));
306 mperf_current_count = calloc(cpu_count, sizeof(unsigned long long));
307 aperf_current_count = calloc(cpu_count, sizeof(unsigned long long));
308 tsc_at_measure_start = calloc(cpu_count, sizeof(unsigned long long));
309 tsc_at_measure_end = calloc(cpu_count, sizeof(unsigned long long));
310 mperf_monitor.name_len = strlen(mperf_monitor.name);
311 return &mperf_monitor;
314 void mperf_unregister(void)
316 free(mperf_previous_count);
317 free(aperf_previous_count);
318 free(mperf_current_count);
319 free(aperf_current_count);
320 free(tsc_at_measure_start);
321 free(tsc_at_measure_end);
325 struct cpuidle_monitor mperf_monitor = {
327 .hw_states_num = MPERF_CSTATE_COUNT,
328 .hw_states = mperf_cstates,
329 .start = mperf_start,
331 .do_register = mperf_register,
332 .unregister = mperf_unregister,
334 .overflow_s = 922000000 /* 922337203 seconds TSC overflow
337 #endif /* #if defined(__i386__) || defined(__x86_64__) */