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-rw-r--r--tools/power/x86/x86_energy_perf_policy/Makefile8
-rw-r--r--tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.8104
-rw-r--r--tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c325
3 files changed, 437 insertions, 0 deletions
diff --git a/tools/power/x86/x86_energy_perf_policy/Makefile b/tools/power/x86/x86_energy_perf_policy/Makefile
new file mode 100644
index 000000000000..f458237fdd79
--- /dev/null
+++ b/tools/power/x86/x86_energy_perf_policy/Makefile
@@ -0,0 +1,8 @@
1x86_energy_perf_policy : x86_energy_perf_policy.c
2
3clean :
4 rm -f x86_energy_perf_policy
5
6install :
7 install x86_energy_perf_policy /usr/bin/
8 install x86_energy_perf_policy.8 /usr/share/man/man8/
diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.8 b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.8
new file mode 100644
index 000000000000..8eaaad648cdb
--- /dev/null
+++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.8
@@ -0,0 +1,104 @@
1.\" This page Copyright (C) 2010 Len Brown <len.brown@intel.com>
2.\" Distributed under the GPL, Copyleft 1994.
3.TH X86_ENERGY_PERF_POLICY 8
4.SH NAME
5x86_energy_perf_policy \- read or write MSR_IA32_ENERGY_PERF_BIAS
6.SH SYNOPSIS
7.ft B
8.B x86_energy_perf_policy
9.RB [ "\-c cpu" ]
10.RB [ "\-v" ]
11.RB "\-r"
12.br
13.B x86_energy_perf_policy
14.RB [ "\-c cpu" ]
15.RB [ "\-v" ]
16.RB 'performance'
17.br
18.B x86_energy_perf_policy
19.RB [ "\-c cpu" ]
20.RB [ "\-v" ]
21.RB 'normal'
22.br
23.B x86_energy_perf_policy
24.RB [ "\-c cpu" ]
25.RB [ "\-v" ]
26.RB 'powersave'
27.br
28.B x86_energy_perf_policy
29.RB [ "\-c cpu" ]
30.RB [ "\-v" ]
31.RB n
32.br
33.SH DESCRIPTION
34\fBx86_energy_perf_policy\fP
35allows software to convey
36its policy for the relative importance of performance
37versus energy savings to the processor.
38
39The processor uses this information in model-specific ways
40when it must select trade-offs between performance and
41energy efficiency.
42
43This policy hint does not supersede Processor Performance states
44(P-states) or CPU Idle power states (C-states), but allows
45software to have influence where it would otherwise be unable
46to express a preference.
47
48For example, this setting may tell the hardware how
49aggressively or conservatively to control frequency
50in the "turbo range" above the explicitly OS-controlled
51P-state frequency range. It may also tell the hardware
52how aggressively is should enter the OS requested C-states.
53
54Support for this feature is indicated by CPUID.06H.ECX.bit3
55per the Intel Architectures Software Developer's Manual.
56
57.SS Options
58\fB-c\fP limits operation to a single CPU.
59The default is to operate on all CPUs.
60Note that MSR_IA32_ENERGY_PERF_BIAS is defined per
61logical processor, but that the initial implementations
62of the MSR were shared among all processors in each package.
63.PP
64\fB-v\fP increases verbosity. By default
65x86_energy_perf_policy is silent.
66.PP
67\fB-r\fP is for "read-only" mode - the unchanged state
68is read and displayed.
69.PP
70.I performance
71Set a policy where performance is paramount.
72The processor will be unwilling to sacrifice any performance
73for the sake of energy saving. This is the hardware default.
74.PP
75.I normal
76Set a policy with a normal balance between performance and energy efficiency.
77The processor will tolerate minor performance compromise
78for potentially significant energy savings.
79This reasonable default for most desktops and servers.
80.PP
81.I powersave
82Set a policy where the processor can accept
83a measurable performance hit to maximize energy efficiency.
84.PP
85.I n
86Set MSR_IA32_ENERGY_PERF_BIAS to the specified number.
87The range of valid numbers is 0-15, where 0 is maximum
88performance and 15 is maximum energy efficiency.
89
90.SH NOTES
91.B "x86_energy_perf_policy "
92runs only as root.
93.SH FILES
94.ta
95.nf
96/dev/cpu/*/msr
97.fi
98
99.SH "SEE ALSO"
100msr(4)
101.PP
102.SH AUTHORS
103.nf
104Written by Len Brown <len.brown@intel.com>
diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
new file mode 100644
index 000000000000..d9678a34dd70
--- /dev/null
+++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
@@ -0,0 +1,325 @@
1/*
2 * x86_energy_perf_policy -- set the energy versus performance
3 * policy preference bias on recent X86 processors.
4 */
5/*
6 * Copyright (c) 2010, Intel Corporation.
7 * Len Brown <len.brown@intel.com>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms and conditions of the GNU General Public License,
11 * version 2, as published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
16 * more details.
17 *
18 * You should have received a copy of the GNU General Public License along with
19 * this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
21 */
22
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; /* set with -v */
35unsigned int read_only; /* set with -r */
36char *progname;
37unsigned long long new_bias;
38int cpu = -1;
39
40/*
41 * Usage:
42 *
43 * -c cpu: limit action to a single CPU (default is all CPUs)
44 * -v: verbose output (can invoke more than once)
45 * -r: read-only, don't change any settings
46 *
47 * performance
48 * Performance is paramount.
49 * Unwilling to sacrafice any performance
50 * for the sake of energy saving. (hardware default)
51 *
52 * normal
53 * Can tolerate minor performance compromise
54 * for potentially significant energy savings.
55 * (reasonable default for most desktops and servers)
56 *
57 * powersave
58 * Can tolerate significant performance hit
59 * to maximize energy savings.
60 *
61 * n
62 * a numerical value to write to the underlying MSR.
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 /* if -r, then should be no additional optind */
100 if (read_only && (argc > optind))
101 usage();
102
103 /*
104 * if no -r , then must be one additional optind
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 * validate_cpuid()
135 * returns on success, quietly exits on failure (make verbose with -v)
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 * Support for MSR_IA32_ENERGY_PERF_BIAS
175 * is indicated by CPUID.06H.ECX.bit3
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; /* success */
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 * run func() on every cpu in /dev/cpu
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}