1 /*
2 * Copyright (c) 2011, 2015, 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 <inttypes.h>
39 #include "com_sun_management_internal_OperatingSystemImpl.h"
40
41 struct ticks {
42 uint64_t used;
43 uint64_t usedKernel;
44 uint64_t total;
45 };
46
47 typedef struct ticks ticks;
48
49 typedef enum {
50 CPU_LOAD_VM_ONLY,
51 CPU_LOAD_GLOBAL,
52 } CpuLoadTarget;
53
54 static struct perfbuf {
55 int nProcs;
56 ticks jvmTicks;
57 ticks cpuTicks;
58 ticks *cpus;
59 } counters;
60
61 #define DEC_64 "%"SCNd64
62
63 static void next_line(FILE *f) {
64 while (fgetc(f) != '\n');
65 }
66
67 /**
68 * Return the total number of ticks since the system was booted.
69 * If the usedTicks parameter is not NULL, it will be filled with
70 * the number of ticks spent on actual processes (user, system or
71 * nice processes) since system boot. Note that this is the total number
72 * of "executed" ticks on _all_ CPU:s, that is on a n-way system it is
73 * n times the number of ticks that has passed in clock time.
74 *
75 * Returns a negative value if the reading of the ticks failed.
76 */
77 static int get_totalticks(int which, ticks *pticks) {
78 FILE *fh;
79 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
80 int n;
81
82 if((fh = fopen("/proc/stat", "r")) == NULL) {
83 return -1;
84 }
85
86 n = fscanf(fh, "cpu " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64,
87 &userTicks, &niceTicks, &systemTicks, &idleTicks);
88
89 // Move to next line
90 next_line(fh);
91
92 //find the line for requested cpu faster to just iterate linefeeds?
93 if (which != -1) {
94 int i;
95 for (i = 0; i < which; i++) {
96 if (fscanf(fh, "cpu%*d " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64, &userTicks, &niceTicks, &systemTicks, &idleTicks) != 4) {
97 fclose(fh);
98 return -2;
99 }
100 next_line(fh);
101 }
102 n = fscanf(fh, "cpu%*d " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64 "\n",
103 &userTicks, &niceTicks, &systemTicks, &idleTicks);
104 }
105
106 fclose(fh);
107 if (n != 4) {
108 return -2;
109 }
110
111 pticks->used = userTicks + niceTicks;
112 pticks->usedKernel = systemTicks;
113 pticks->total = userTicks + niceTicks + systemTicks + idleTicks;
114
115 return 0;
116 }
117
118 static int vread_statdata(const char *procfile, const char *fmt, va_list args) {
119 FILE *f;
120 int n;
121 char buf[2048];
122
123 if ((f = fopen(procfile, "r")) == NULL) {
124 return -1;
125 }
126
127 if ((n = fread(buf, 1, sizeof(buf), f)) != -1) {
128 char *tmp;
129
130 buf[n-1] = '\0';
131 /** skip through pid and exec name. the exec name _could be wacky_ (renamed) and
132 * make scanf go mupp.
133 */
134 if ((tmp = strrchr(buf, ')')) != NULL) {
135 // skip the ')' and the following space but check that the buffer is long enough
136 tmp += 2;
137 if (tmp < buf + n) {
138 n = vsscanf(tmp, fmt, args);
139 }
140 }
141 }
142
143 fclose(f);
144
145 return n;
146 }
147
148 static int read_statdata(const char *procfile, const char *fmt, ...) {
149 int n;
150 va_list args;
151
152 va_start(args, fmt);
153 n = vread_statdata(procfile, fmt, args);
154 va_end(args);
155 return n;
156 }
157
158 /** read user and system ticks from a named procfile, assumed to be in 'stat' format then. */
159 static int read_ticks(const char *procfile, uint64_t *userTicks, uint64_t *systemTicks) {
160 return read_statdata(procfile, "%*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u "DEC_64" "DEC_64,
161 userTicks, systemTicks
162 );
163 }
164
165 /**
166 * Return the number of ticks spent in any of the processes belonging
167 * to the JVM on any CPU.
168 */
169 static int get_jvmticks(ticks *pticks) {
170 uint64_t userTicks;
171 uint64_t systemTicks;
172
173 if (read_ticks("/proc/self/stat", &userTicks, &systemTicks) < 0) {
174 return -1;
175 }
176
177 // get the total
178 if (get_totalticks(-1, pticks) < 0) {
179 return -1;
180 }
181
182 pticks->used = userTicks;
183 pticks->usedKernel = systemTicks;
184
185 return 0;
186 }
187
188 /**
189 * This method must be called first, before any data can be gathererd.
190 */
191 int perfInit() {
192 static int initialized=1;
193
194 if (!initialized) {
195 int i;
196
197 int n = sysconf(_SC_NPROCESSORS_ONLN);
198 if (n <= 0) {
199 n = 1;
200 }
201
202 counters.cpus = calloc(n,sizeof(ticks));
203 if (counters.cpus != NULL) {
204 // For the CPU load
205 get_totalticks(-1, &counters.cpuTicks);
206
207 for (i = 0; i < n; i++) {
208 get_totalticks(i, &counters.cpus[i]);
209 }
210 // For JVM load
211 get_jvmticks(&counters.jvmTicks);
212 initialized = 1;
213 }
214 }
215
216 return initialized ? 0 : -1;
217 }
218
219 #define MAX(a,b) (a>b?a:b)
220 #define MIN(a,b) (a<b?a:b)
221
222 static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
223
224 /**
225 * Return the load of the CPU as a double. 1.0 means the CPU process uses all
226 * available time for user or system processes, 0.0 means the CPU uses all time
227 * being idle.
228 *
229 * Returns a negative value if there is a problem in determining the CPU load.
230 */
231
232 static double get_cpuload_internal(int which, double *pkernelLoad, CpuLoadTarget target) {
233 uint64_t udiff, kdiff, tdiff;
234 ticks *pticks, tmp;
235 double user_load = -1.0;
236 int failed = 0;
237
238 *pkernelLoad = 0.0;
239
240 pthread_mutex_lock(&lock);
241
242 if(perfInit() == 0) {
243
244 if (target == CPU_LOAD_VM_ONLY) {
245 pticks = &counters.jvmTicks;
246 } else if (which == -1) {
247 pticks = &counters.cpuTicks;
248 } else {
249 pticks = &counters.cpus[which];
250 }
251
252 tmp = *pticks;
253
254 if (target == CPU_LOAD_VM_ONLY) {
255 if (get_jvmticks(pticks) != 0) {
256 failed = 1;
257 }
258 } else if (get_totalticks(which, pticks) < 0) {
259 failed = 1;
260 }
261
262 if(!failed) {
263 // seems like we sometimes end up with less kernel ticks when
264 // reading /proc/self/stat a second time, timing issue between cpus?
265 if (pticks->usedKernel < tmp.usedKernel) {
266 kdiff = 0;
267 } else {
268 kdiff = pticks->usedKernel - tmp.usedKernel;
269 }
270 tdiff = pticks->total - tmp.total;
271 udiff = pticks->used - tmp.used;
272
273 if (tdiff == 0) {
274 user_load = 0;
275 } else {
276 if (tdiff < (udiff + kdiff)) {
277 tdiff = udiff + kdiff;
278 }
279 *pkernelLoad = (kdiff / (double)tdiff);
280 // BUG9044876, normalize return values to sane values
281 *pkernelLoad = MAX(*pkernelLoad, 0.0);
282 *pkernelLoad = MIN(*pkernelLoad, 1.0);
283
284 user_load = (udiff / (double)tdiff);
285 user_load = MAX(user_load, 0.0);
286 user_load = MIN(user_load, 1.0);
287 }
288 }
289 }
290 pthread_mutex_unlock(&lock);
291 return user_load;
292 }
293
294 double get_cpu_load(int which) {
295 double u, s;
296 u = get_cpuload_internal(which, &s, CPU_LOAD_GLOBAL);
297 if (u < 0) {
298 return -1.0;
299 }
300 // Cap total systemload to 1.0
301 return MIN((u + s), 1.0);
302 }
303
304 double get_process_load() {
305 double u, s;
306 u = get_cpuload_internal(-1, &s, CPU_LOAD_VM_ONLY);
307 if (u < 0) {
308 return -1.0;
309 }
310 return u + s;
311 }
312
313 JNIEXPORT jdouble JNICALL
314 Java_com_sun_management_internal_OperatingSystemImpl_getSystemCpuLoad0
315 (JNIEnv *env, jobject dummy)
316 {
317 if(perfInit() == 0) {
318 return get_cpu_load(-1);
319 } else {
320 return -1.0;
321 }
322 }
323
324 JNIEXPORT jdouble JNICALL
325 Java_com_sun_management_internal_OperatingSystemImpl_getProcessCpuLoad0
326 (JNIEnv *env, jobject dummy)
327 {
328 if(perfInit() == 0) {
329 return get_process_load();
330 } else {
331 return -1.0;
332 }
333 }