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23#include <stdio.h>
24#include <unistd.h>
25#include <sys/types.h>
26#include <sys/stat.h>
27#include <sys/resource.h>
28#include <fcntl.h>
29#include <signal.h>
30#include <sys/time.h>
31#include <stdlib.h>
32#include <string.h>
33
34unsigned int verbose;
35unsigned int read_only;
36char *progname;
37unsigned long long new_bias;
38int cpu = -1;
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63
64void usage(void)
65{
66 printf("%s: [-c cpu] [-v] "
67 "(-r | 'performance' | 'normal' | 'powersave' | n)\n",
68 progname);
69 exit(1);
70}
71
72#define MSR_IA32_ENERGY_PERF_BIAS 0x000001b0
73
74#define BIAS_PERFORMANCE 0
75#define BIAS_BALANCE 6
76#define BIAS_POWERSAVE 15
77
78void cmdline(int argc, char **argv)
79{
80 int opt;
81
82 progname = argv[0];
83
84 while ((opt = getopt(argc, argv, "+rvc:")) != -1) {
85 switch (opt) {
86 case 'c':
87 cpu = atoi(optarg);
88 break;
89 case 'r':
90 read_only = 1;
91 break;
92 case 'v':
93 verbose++;
94 break;
95 default:
96 usage();
97 }
98 }
99
100 if (read_only && (argc > optind))
101 usage();
102
103
104
105
106 if (!read_only) {
107
108 if (argc != optind + 1) {
109 printf("must supply -r or policy param\n");
110 usage();
111 }
112
113 if (!strcmp("performance", argv[optind])) {
114 new_bias = BIAS_PERFORMANCE;
115 } else if (!strcmp("normal", argv[optind])) {
116 new_bias = BIAS_BALANCE;
117 } else if (!strcmp("powersave", argv[optind])) {
118 new_bias = BIAS_POWERSAVE;
119 } else {
120 char *endptr;
121
122 new_bias = strtoull(argv[optind], &endptr, 0);
123 if (endptr == argv[optind] ||
124 new_bias > BIAS_POWERSAVE) {
125 fprintf(stderr, "invalid value: %s\n",
126 argv[optind]);
127 usage();
128 }
129 }
130 }
131}
132
133
134
135
136
137void validate_cpuid(void)
138{
139 unsigned int eax, ebx, ecx, edx, max_level;
140 char brand[16];
141 unsigned int fms, family, model, stepping;
142
143 eax = ebx = ecx = edx = 0;
144
145 asm("cpuid" : "=a" (max_level), "=b" (ebx), "=c" (ecx),
146 "=d" (edx) : "a" (0));
147
148 if (ebx != 0x756e6547 || edx != 0x49656e69 || ecx != 0x6c65746e) {
149 if (verbose)
150 fprintf(stderr, "%.4s%.4s%.4s != GenuineIntel",
151 (char *)&ebx, (char *)&edx, (char *)&ecx);
152 exit(1);
153 }
154
155 asm("cpuid" : "=a" (fms), "=c" (ecx), "=d" (edx) : "a" (1) : "ebx");
156 family = (fms >> 8) & 0xf;
157 model = (fms >> 4) & 0xf;
158 stepping = fms & 0xf;
159 if (family == 6 || family == 0xf)
160 model += ((fms >> 16) & 0xf) << 4;
161
162 if (verbose > 1)
163 printf("CPUID %s %d levels family:model:stepping "
164 "0x%x:%x:%x (%d:%d:%d)\n", brand, max_level,
165 family, model, stepping, family, model, stepping);
166
167 if (!(edx & (1 << 5))) {
168 if (verbose)
169 printf("CPUID: no MSR\n");
170 exit(1);
171 }
172
173
174
175
176
177 asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (6));
178 if (verbose)
179 printf("CPUID.06H.ECX: 0x%x\n", ecx);
180 if (!(ecx & (1 << 3))) {
181 if (verbose)
182 printf("CPUID: No MSR_IA32_ENERGY_PERF_BIAS\n");
183 exit(1);
184 }
185 return;
186}
187
188unsigned long long get_msr(int cpu, int offset)
189{
190 unsigned long long msr;
191 char msr_path[32];
192 int retval;
193 int fd;
194
195 sprintf(msr_path, "/dev/cpu/%d/msr", cpu);
196 fd = open(msr_path, O_RDONLY);
197 if (fd < 0) {
198 printf("Try \"# modprobe msr\"\n");
199 perror(msr_path);
200 exit(1);
201 }
202
203 retval = pread(fd, &msr, sizeof msr, offset);
204
205 if (retval != sizeof msr) {
206 printf("pread cpu%d 0x%x = %d\n", cpu, offset, retval);
207 exit(-2);
208 }
209 close(fd);
210 return msr;
211}
212
213unsigned long long put_msr(int cpu, unsigned long long new_msr, int offset)
214{
215 unsigned long long old_msr;
216 char msr_path[32];
217 int retval;
218 int fd;
219
220 sprintf(msr_path, "/dev/cpu/%d/msr", cpu);
221 fd = open(msr_path, O_RDWR);
222 if (fd < 0) {
223 perror(msr_path);
224 exit(1);
225 }
226
227 retval = pread(fd, &old_msr, sizeof old_msr, offset);
228 if (retval != sizeof old_msr) {
229 perror("pwrite");
230 printf("pread cpu%d 0x%x = %d\n", cpu, offset, retval);
231 exit(-2);
232 }
233
234 retval = pwrite(fd, &new_msr, sizeof new_msr, offset);
235 if (retval != sizeof new_msr) {
236 perror("pwrite");
237 printf("pwrite cpu%d 0x%x = %d\n", cpu, offset, retval);
238 exit(-2);
239 }
240
241 close(fd);
242
243 return old_msr;
244}
245
246void print_msr(int cpu)
247{
248 printf("cpu%d: 0x%016llx\n",
249 cpu, get_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS));
250}
251
252void update_msr(int cpu)
253{
254 unsigned long long previous_msr;
255
256 previous_msr = put_msr(cpu, new_bias, MSR_IA32_ENERGY_PERF_BIAS);
257
258 if (verbose)
259 printf("cpu%d msr0x%x 0x%016llx -> 0x%016llx\n",
260 cpu, MSR_IA32_ENERGY_PERF_BIAS, previous_msr, new_bias);
261
262 return;
263}
264
265char *proc_stat = "/proc/stat";
266
267
268
269void for_every_cpu(void (func)(int))
270{
271 FILE *fp;
272 int retval;
273
274 fp = fopen(proc_stat, "r");
275 if (fp == NULL) {
276 perror(proc_stat);
277 exit(1);
278 }
279
280 retval = fscanf(fp, "cpu %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d\n");
281 if (retval != 0) {
282 perror("/proc/stat format");
283 exit(1);
284 }
285
286 while (1) {
287 int cpu;
288
289 retval = fscanf(fp,
290 "cpu%u %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d\n",
291 &cpu);
292 if (retval != 1)
293 return;
294
295 func(cpu);
296 }
297 fclose(fp);
298}
299
300int main(int argc, char **argv)
301{
302 cmdline(argc, argv);
303
304 if (verbose > 1)
305 printf("x86_energy_perf_policy Nov 24, 2010"
306 " - Len Brown <lenb@kernel.org>\n");
307 if (verbose > 1 && !read_only)
308 printf("new_bias %lld\n", new_bias);
309
310 validate_cpuid();
311
312 if (cpu != -1) {
313 if (read_only)
314 print_msr(cpu);
315 else
316 update_msr(cpu);
317 } else {
318 if (read_only)
319 for_every_cpu(print_msr);
320 else
321 for_every_cpu(update_msr);
322 }
323
324 return 0;
325}
326