1/*
2 * Copyright (c) 2013-2014 Oracle and/or its affiliates. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of
7 * the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17 *
18 * Author: Alexey Kodanev <alexey.kodanev@oracle.com>
19 *
20 * Check support for disabling dynamic overclocking in acpi_cpufreq driver.
21 * Required Linux 3.7+.
22 *
23 * The test compares time spent on sum calculation with/without
24 * boost-disable bit. If boost is enabled we can get a slightly shorter
25 * time period. Measure elapsed time instead of sysfs cpuinfo_cur_freq value,
26 * because after the upstream commit 8673b83bf2f013379453b4779047bf3c6ae387e4,
27 * current cpu frequency became target cpu frequency.
28 */
29
30#define _GNU_SOURCE
31#include <sched.h>
32#include <time.h>
33
34#include "test.h"
35#include "lapi/posix_clocks.h"
36#include "safe_macros.h"
37
38char *TCID = "cpufreq_boost";
39
40#define SYSFS_CPU_DIR "/sys/devices/system/cpu/"
41
42struct cpufreq_driver_info {
43	char *name;
44	int off;
45	char *on_str;
46	char *off_str;
47	char *file;
48};
49static const struct cpufreq_driver_info cdrv[] = {
50	{ "acpi_cpufreq", 0, "1", "0", SYSFS_CPU_DIR "cpufreq/boost" },
51	{ "intel_pstate", 1, "0", "1", SYSFS_CPU_DIR "intel_pstate/no_turbo" },
52};
53static int id = -1;
54
55static int boost_value;
56
57const char governor[]	= SYSFS_CPU_DIR "cpu0/cpufreq/scaling_governor";
58static char governor_name[16];
59
60const char maxspeed[]	= SYSFS_CPU_DIR "cpu0/cpufreq/scaling_max_freq";
61
62static void cleanup(void)
63{
64	FILE_PRINTF(cdrv[id].file, "%d", boost_value);
65
66	if (governor[0] != '\0')
67		FILE_PRINTF(governor, "%s", governor_name);
68}
69
70static void setup(void)
71{
72	int fd;
73	unsigned int i;
74	tst_require_root();
75
76	for (i = 0; i < ARRAY_SIZE(cdrv); ++i) {
77		fd = open(cdrv[i].file, O_RDWR);
78		if (fd == -1)
79			continue;
80
81		id = i;
82		close(fd);
83		break;
84	}
85
86	if (id == -1)
87		tst_brkm(TCONF, NULL, "overclock not supported");
88
89	tst_resm(TINFO, "found '%s' driver, sysfs knob '%s'",
90		cdrv[id].name, cdrv[id].file);
91
92	tst_sig(FORK, DEF_HANDLER, cleanup);
93
94	SAFE_FILE_SCANF(NULL, cdrv[i].file, "%d", &boost_value);
95
96	/* change cpu0 scaling governor */
97	SAFE_FILE_SCANF(NULL, governor, "%s", governor_name);
98	SAFE_FILE_PRINTF(cleanup, governor, "%s", "performance");
99
100	/* use only cpu0 */
101	cpu_set_t set;
102	CPU_ZERO(&set);
103	CPU_SET(0, &set);
104	if (sched_setaffinity(0, sizeof(cpu_set_t), &set) < 0)
105		tst_brkm(TBROK | TERRNO, cleanup, "failed to set CPU0");
106
107	struct sched_param params;
108	params.sched_priority = sched_get_priority_max(SCHED_FIFO);
109	if (sched_setscheduler(getpid(), SCHED_FIFO, &params)) {
110		tst_resm(TWARN | TERRNO,
111			"failed to set FIFO sched with max priority");
112	}
113}
114
115static int load_cpu(int max_freq_khz)
116{
117	int sum = 0, i = 0, total_time_ms;
118	struct timespec tv_start, tv_end;
119
120	const int max_sum = max_freq_khz / 1000;
121	const int units = 1000000; /* Mhz */
122
123	clock_gettime(CLOCK_MONOTONIC_RAW, &tv_start);
124
125	do {
126		for (i = 0; i < units; ++i)
127			asm ("" : : : "memory");
128	} while (++sum < max_sum);
129
130	clock_gettime(CLOCK_MONOTONIC_RAW, &tv_end);
131
132	total_time_ms = (tv_end.tv_sec - tv_start.tv_sec) * 1000 +
133		(tv_end.tv_nsec - tv_start.tv_nsec) / 1000000;
134
135	if (!total_time_ms)
136		tst_brkm(TBROK, cleanup, "time period is 0");
137
138	tst_resm(TINFO, "elapsed time is %d ms", total_time_ms);
139
140	return total_time_ms;
141}
142
143static void test_run(void)
144{
145	int boost_time, boost_off_time, max_freq_khz;
146	SAFE_FILE_SCANF(cleanup, maxspeed, "%d", &max_freq_khz);
147	tst_resm(TINFO, "maximum speed is %d KHz", max_freq_khz);
148
149	/* Enable boost */
150	if (boost_value == cdrv[id].off)
151		SAFE_FILE_PRINTF(cleanup, cdrv[id].file, "%s", cdrv[id].on_str);
152	tst_resm(TINFO, "load CPU0 with boost enabled");
153	boost_time = load_cpu(max_freq_khz);
154
155	/* Disable boost */
156	SAFE_FILE_PRINTF(cleanup, cdrv[id].file, "%s", cdrv[id].off_str);
157	tst_resm(TINFO, "load CPU0 with boost disabled");
158	boost_off_time = load_cpu(max_freq_khz);
159
160	boost_off_time *= .98;
161
162	tst_resm((boost_time < boost_off_time) ? TPASS : TFAIL,
163		"compare time spent with and without boost (-2%%)");
164}
165
166int main(int argc, char *argv[])
167{
168	tst_parse_opts(argc, argv, NULL, NULL);
169
170	setup();
171
172	test_run();
173
174	cleanup();
175
176	tst_exit();
177}
178