perfMemory.cpp revision 3465:d2a62e0f25eb 
1/*
2 * Copyright (c) 2001, 2010, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25#include "precompiled.hpp"
26#include "memory/allocation.inline.hpp"
27#include "runtime/arguments.hpp"
28#include "runtime/java.hpp"
29#include "runtime/mutex.hpp"
30#include "runtime/mutexLocker.hpp"
31#include "runtime/os.hpp"
32#include "runtime/perfData.hpp"
33#include "runtime/perfMemory.hpp"
34#include "runtime/statSampler.hpp"
35#include "utilities/globalDefinitions.hpp"
36
37// Prefix of performance data file.
38const char               PERFDATA_NAME[] = "hsperfdata";
39
40// Add 1 for the '_' character between PERFDATA_NAME and pid. The '\0' terminating
41// character will be included in the sizeof(PERFDATA_NAME) operation.
42static const size_t PERFDATA_FILENAME_LEN = sizeof(PERFDATA_NAME) +
43                                            UINT_CHARS + 1;
44
45char*                    PerfMemory::_start = NULL;
46char*                    PerfMemory::_end = NULL;
47char*                    PerfMemory::_top = NULL;
48size_t                   PerfMemory::_capacity = 0;
49jint                     PerfMemory::_initialized = false;
50PerfDataPrologue*        PerfMemory::_prologue = NULL;
51
52void perfMemory_init() {
53
54  if (!UsePerfData) return;
55
56  PerfMemory::initialize();
57}
58
59void perfMemory_exit() {
60
61  if (!UsePerfData) return;
62  if (!PerfMemory::is_initialized()) return;
63
64  // if the StatSampler is active, then we don't want to remove
65  // resources it may be dependent on. Typically, the StatSampler
66  // is disengaged from the watcher thread when this method is called,
67  // but it is not disengaged if this method is invoked during a
68  // VM abort.
69  //
70  if (!StatSampler::is_active())
71    PerfDataManager::destroy();
72
73  // remove the persistent external resources, if any. this method
74  // does not unmap or invalidate any virtual memory allocated during
75  // initialization.
76  //
77  PerfMemory::destroy();
78}
79
80void PerfMemory::initialize() {
81
82  if (_prologue != NULL)
83    // initialization already performed
84    return;
85
86  size_t capacity = align_size_up(PerfDataMemorySize,
87                                  os::vm_allocation_granularity());
88
89  if (PerfTraceMemOps) {
90    tty->print("PerfDataMemorySize = " SIZE_FORMAT ","
91               " os::vm_allocation_granularity = " SIZE_FORMAT ","
92               " adjusted size = " SIZE_FORMAT "\n",
93               PerfDataMemorySize,
94               os::vm_allocation_granularity(),
95               capacity);
96  }
97
98  // allocate PerfData memory region
99  create_memory_region(capacity);
100
101  if (_start == NULL) {
102
103    // the PerfMemory region could not be created as desired. Rather
104    // than terminating the JVM, we revert to creating the instrumentation
105    // on the C heap. When running in this mode, external monitoring
106    // clients cannot attach to and monitor this JVM.
107    //
108    // the warning is issued only in debug mode in order to avoid
109    // additional output to the stdout or stderr output streams.
110    //
111    if (PrintMiscellaneous && Verbose) {
112      warning("Could not create PerfData Memory region, reverting to malloc");
113    }
114
115    _prologue = NEW_C_HEAP_OBJ(PerfDataPrologue, mtInternal);
116  }
117  else {
118
119    // the PerfMemory region was created as expected.
120
121    if (PerfTraceMemOps) {
122      tty->print("PerfMemory created: address = " INTPTR_FORMAT ","
123                 " size = " SIZE_FORMAT "\n",
124                 (void*)_start,
125                 _capacity);
126    }
127
128    _prologue = (PerfDataPrologue *)_start;
129    _end = _start + _capacity;
130    _top = _start + sizeof(PerfDataPrologue);
131  }
132
133  assert(_prologue != NULL, "prologue pointer must be initialized");
134
135#ifdef VM_LITTLE_ENDIAN
136  _prologue->magic = (jint)0xc0c0feca;
137  _prologue->byte_order = PERFDATA_LITTLE_ENDIAN;
138#else
139  _prologue->magic = (jint)0xcafec0c0;
140  _prologue->byte_order = PERFDATA_BIG_ENDIAN;
141#endif
142
143  _prologue->major_version = PERFDATA_MAJOR_VERSION;
144  _prologue->minor_version = PERFDATA_MINOR_VERSION;
145  _prologue->accessible = 0;
146
147  _prologue->entry_offset = sizeof(PerfDataPrologue);
148  _prologue->num_entries = 0;
149  _prologue->used = 0;
150  _prologue->overflow = 0;
151  _prologue->mod_time_stamp = 0;
152
153  OrderAccess::release_store(&_initialized, 1);
154}
155
156void PerfMemory::destroy() {
157
158  assert(_prologue != NULL, "prologue pointer must be initialized");
159
160  if (_start != NULL && _prologue->overflow != 0) {
161
162    // This state indicates that the contiguous memory region exists and
163    // that it wasn't large enough to hold all the counters. In this case,
164    // we output a warning message to the user on exit if the -XX:+Verbose
165    // flag is set (a debug only flag). External monitoring tools can detect
166    // this condition by monitoring the _prologue->overflow word.
167    //
168    // There are two tunables that can help resolve this issue:
169    //   - increase the size of the PerfMemory with -XX:PerfDataMemorySize=<n>
170    //   - decrease the maximum string constant length with
171    //     -XX:PerfMaxStringConstLength=<n>
172    //
173    if (PrintMiscellaneous && Verbose) {
174      warning("PerfMemory Overflow Occurred.\n"
175              "\tCapacity = " SIZE_FORMAT " bytes"
176              "  Used = " SIZE_FORMAT " bytes"
177              "  Overflow = " INT32_FORMAT " bytes"
178              "\n\tUse -XX:PerfDataMemorySize=<size> to specify larger size.",
179              PerfMemory::capacity(),
180              PerfMemory::used(),
181              _prologue->overflow);
182    }
183  }
184
185  if (_start != NULL) {
186
187    // this state indicates that the contiguous memory region was successfully
188    // and that persistent resources may need to be cleaned up. This is
189    // expected to be the typical condition.
190    //
191    delete_memory_region();
192  }
193
194  _start = NULL;
195  _end = NULL;
196  _top = NULL;
197  _prologue = NULL;
198  _capacity = 0;
199}
200
201// allocate an aligned block of memory from the PerfData memory
202// region. This method assumes that the PerfData memory region
203// was aligned on a double word boundary when created.
204//
205char* PerfMemory::alloc(size_t size) {
206
207  if (!UsePerfData) return NULL;
208
209  MutexLocker ml(PerfDataMemAlloc_lock);
210
211  assert(_prologue != NULL, "called before initialization");
212
213  // check that there is enough memory for this request
214  if ((_top + size) >= _end) {
215
216    _prologue->overflow += (jint)size;
217
218    return NULL;
219  }
220
221  char* result = _top;
222
223  _top += size;
224
225  assert(contains(result), "PerfData memory pointer out of range");
226
227  _prologue->used = (jint)used();
228  _prologue->num_entries = _prologue->num_entries + 1;
229
230  return result;
231}
232
233void PerfMemory::mark_updated() {
234  if (!UsePerfData) return;
235
236  _prologue->mod_time_stamp = os::elapsed_counter();
237}
238
239// Returns the complete path including the file name of performance data file.
240// Caller is expected to release the allocated memory.
241char* PerfMemory::get_perfdata_file_path() {
242  char* dest_file = NULL;
243
244  if (PerfDataSaveFile != NULL) {
245    // dest_file_name stores the validated file name if file_name
246    // contains %p which will be replaced by pid.
247    dest_file = NEW_C_HEAP_ARRAY(char, JVM_MAXPATHLEN, mtInternal);
248    if(!Arguments::copy_expand_pid(PerfDataSaveFile, strlen(PerfDataSaveFile),
249                                   dest_file, JVM_MAXPATHLEN)) {
250      FREE_C_HEAP_ARRAY(char, dest_file, mtInternal);
251      if (PrintMiscellaneous && Verbose) {
252        warning("Invalid performance data file path name specified, "\
253                "fall back to a default name");
254      }
255    } else {
256      return dest_file;
257    }
258  }
259  // create the name of the file for retaining the instrumentation memory.
260  dest_file = NEW_C_HEAP_ARRAY(char, PERFDATA_FILENAME_LEN, mtInternal);
261  jio_snprintf(dest_file, PERFDATA_FILENAME_LEN,
262               "%s_%d", PERFDATA_NAME, os::current_process_id());
263
264  return dest_file;
265}
266