1 /*
2 * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 #include <stdio.h>
27 #include <stdint.h>
28 #include <stdarg.h>
29 #include <unistd.h>
30 #include <errno.h>
31 #include <string.h>
32 #include <sys/resource.h>
33 #include <sys/types.h>
34 #include <dirent.h>
35 #include <stdlib.h>
36 #include <dlfcn.h>
37 #include <pthread.h>
38 #include "com_sun_management_UnixOperatingSystem.h"
39
40 struct ticks {
41 uint64_t used;
42 uint64_t usedKernel;
43 uint64_t total;
44 };
45
46 typedef struct ticks ticks;
47
48 typedef enum {
49 CPU_LOAD_VM_ONLY,
50 CPU_LOAD_GLOBAL,
51 } CpuLoadTarget;
52
53 static struct perfbuf {
54 int nProcs;
55 ticks jvmTicks;
56 ticks cpuTicks;
57 ticks *cpus;
58 } counters;
59
60 #define DEC_64 "%lld"
61
62 static void next_line(FILE *f) {
63 while (fgetc(f) != '\n');
64 }
65
66 /**
67 * Return the total number of ticks since the system was booted.
68 * If the usedTicks parameter is not NULL, it will be filled with
69 * the number of ticks spent on actual processes (user, system or
70 * nice processes) since system boot. Note that this is the total number
71 * of "executed" ticks on _all_ CPU:s, that is on a n-way system it is
72 * n times the number of ticks that has passed in clock time.
73 *
74 * Returns a negative value if the reading of the ticks failed.
75 */
76 static int get_totalticks(int which, ticks *pticks) {
77 FILE *fh;
78 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
79 int n;
80
81 if((fh = fopen("/proc/stat", "r")) == NULL) {
82 return -1;
83 }
84
85 n = fscanf(fh, "cpu " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64,
86 &userTicks, &niceTicks, &systemTicks, &idleTicks);
87
88 // Move to next line
89 next_line(fh);
90
91 //find the line for requested cpu faster to just iterate linefeeds?
92 if (which != -1) {
93 int i;
94 for (i = 0; i < which; i++) {
95 if (fscanf(fh, "cpu%*d " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64, &userTicks, &niceTicks, &systemTicks, &idleTicks) != 4) {
96 fclose(fh);
97 return -2;
98 }
99 next_line(fh);
100 }
101 n = fscanf(fh, "cpu%*d " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64 "\n",
102 &userTicks, &niceTicks, &systemTicks, &idleTicks);
103 }
104
105 fclose(fh);
106 if (n != 4) {
107 return -2;
108 }
109
110 pticks->used = userTicks + niceTicks;
111 pticks->usedKernel = systemTicks;
112 pticks->total = userTicks + niceTicks + systemTicks + idleTicks;
113
114 return 0;
115 }
116
117 static int vread_statdata(const char *procfile, const char *fmt, va_list args) {
118 FILE *f;
119 int n;
120 char buf[2048];
121
122 if ((f = fopen(procfile, "r")) == NULL) {
123 return -1;
124 }
125
126 if ((n = fread(buf, 1, sizeof(buf), f)) != -1) {
127 char *tmp;
128
129 buf[n-1] = '\0';
130 /** skip through pid and exec name. the exec name _could be wacky_ (renamed) and
131 * make scanf go mupp.
132 */
133 if ((tmp = strrchr(buf, ')')) != NULL) {
134 // skip the ')' and the following space but check that the buffer is long enough
135 tmp += 2;
136 if (tmp < buf + n) {
137 n = vsscanf(tmp, fmt, args);
138 }
139 }
140 }
141
142 fclose(f);
143
144 return n;
145 }
146
147 static int read_statdata(const char *procfile, const char *fmt, ...) {
148 int n;
149 va_list args;
150
151 va_start(args, fmt);
152 n = vread_statdata(procfile, fmt, args);
153 va_end(args);
154 return n;
155 }
156
157 /** read user and system ticks from a named procfile, assumed to be in 'stat' format then. */
158 static int read_ticks(const char *procfile, uint64_t *userTicks, uint64_t *systemTicks) {
159 return read_statdata(procfile, "%*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u "DEC_64" "DEC_64,
160 userTicks, systemTicks
161 );
162 }
163
164 /**
165 * Return the number of ticks spent in any of the processes belonging
166 * to the JVM on any CPU.
167 */
168 static int get_jvmticks(ticks *pticks) {
169 uint64_t userTicks;
170 uint64_t systemTicks;
171
172 if (read_ticks("/proc/self/stat", &userTicks, &systemTicks) < 0) {
173 return -1;
174 }
175
176 // get the total
177 if (get_totalticks(-1, pticks) < 0) {
178 return -1;
179 }
180
181 pticks->used = userTicks;
182 pticks->usedKernel = systemTicks;
183
184 return 0;
185 }
186
187 /**
188 * This method must be called first, before any data can be gathererd.
189 */
190 int perfInit() {
191 static int initialized=1;
192
193 if (!initialized) {
194 int i;
195
196 int n = sysconf(_SC_NPROCESSORS_ONLN);
197 if (n <= 0) {
198 n = 1;
199 }
200
201 counters.cpus = calloc(n,sizeof(ticks));
202 if (counters.cpus != NULL) {
203 // For the CPU load
204 get_totalticks(-1, &counters.cpuTicks);
205
206 for (i = 0; i < n; i++) {
207 get_totalticks(i, &counters.cpus[i]);
208 }
209 // For JVM load
210 get_jvmticks(&counters.jvmTicks);
211 initialized = 1;
212 }
213 }
214
215 return initialized ? 0 : -1;
216 }
217
218 #define MAX(a,b) (a>b?a:b)
219 #define MIN(a,b) (a<b?a:b)
220
221 static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
222
223 /**
224 * Return the load of the CPU as a double. 1.0 means the CPU process uses all
225 * available time for user or system processes, 0.0 means the CPU uses all time
226 * being idle.
227 *
228 * Returns a negative value if there is a problem in determining the CPU load.
229 */
230
231 static double get_cpuload_internal(int which, double *pkernelLoad, CpuLoadTarget target) {
232 uint64_t udiff, kdiff, tdiff;
233 ticks *pticks, tmp;
234 double user_load = -1.0;
235 int failed = 0;
236
237 *pkernelLoad = 0.0;
238
239 pthread_mutex_lock(&lock);
240
241 if(perfInit() == 0) {
242
243 if (target == CPU_LOAD_VM_ONLY) {
244 pticks = &counters.jvmTicks;
245 } else if (which == -1) {
246 pticks = &counters.cpuTicks;
247 } else {
248 pticks = &counters.cpus[which];
249 }
250
251 tmp = *pticks;
252
253 if (target == CPU_LOAD_VM_ONLY) {
254 if (get_jvmticks(pticks) != 0) {
255 failed = 1;
256 }
257 } else if (get_totalticks(which, pticks) < 0) {
258 failed = 1;
259 }
260
261 if(!failed) {
262 // seems like we sometimes end up with less kernel ticks when
263 // reading /proc/self/stat a second time, timing issue between cpus?
264 if (pticks->usedKernel < tmp.usedKernel) {
265 kdiff = 0;
266 } else {
267 kdiff = pticks->usedKernel - tmp.usedKernel;
268 }
269 tdiff = pticks->total - tmp.total;
270 udiff = pticks->used - tmp.used;
271
272 if (tdiff == 0) {
273 user_load = 0;
274 } else {
275 if (tdiff < (udiff + kdiff)) {
276 tdiff = udiff + kdiff;
277 }
278 *pkernelLoad = (kdiff / (double)tdiff);
279 // BUG9044876, normalize return values to sane values
280 *pkernelLoad = MAX(*pkernelLoad, 0.0);
281 *pkernelLoad = MIN(*pkernelLoad, 1.0);
282
283 user_load = (udiff / (double)tdiff);
284 user_load = MAX(user_load, 0.0);
285 user_load = MIN(user_load, 1.0);
286 }
287 }
288 }
289 pthread_mutex_unlock(&lock);
290 return user_load;
291 }
292
293 double get_cpu_load(int which) {
294 double u, s;
295 u = get_cpuload_internal(which, &s, CPU_LOAD_GLOBAL);
296 if (u < 0) {
297 return -1.0;
298 }
299 // Cap total systemload to 1.0
300 return MIN((u + s), 1.0);
301 }
302
303 double get_process_load() {
304 double u, s;
305 u = get_cpuload_internal(-1, &s, CPU_LOAD_VM_ONLY);
306 if (u < 0) {
307 return -1.0;
308 }
309 return u + s;
310 }
311
312 JNIEXPORT jdouble JNICALL
313 Java_com_sun_management_UnixOperatingSystem_getSystemCpuLoad
314 (JNIEnv *env, jobject dummy)
315 {
316 if(perfInit() == 0) {
317 return get_cpu_load(-1);
318 } else {
319 return -1.0;
320 }
321 }
322
323 JNIEXPORT jdouble JNICALL
324 Java_com_sun_management_UnixOperatingSystem_getProcessCpuLoad
325 (JNIEnv *env, jobject dummy)
326 {
327 if(perfInit() == 0) {
328 return get_process_load();
329 } else {
330 return -1.0;
331 }
332 }