comparison src/hotspot/share/jfr/leakprofiler/checkpoint/eventEmitter.cpp @ 55571:49102ba8cf14

8214542: JFR: Old Object Sample event slow on a deep heap in debug builds Reviewed-by: egahlin, rwestberg
author mgronlun
date Wed, 03 Jul 2019 11:34:46 +0200
parents
children 90ead0febf56
comparison
equal deleted inserted replaced
-1:000000000000 0:32ffe48e787a
1 /*
2 * Copyright (c) 2019, 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.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jfr/jfrEvents.hpp"
27 #include "jfr/leakprofiler/chains/edgeStore.hpp"
28 #include "jfr/leakprofiler/chains/pathToGcRootsOperation.hpp"
29 #include "jfr/leakprofiler/checkpoint/eventEmitter.hpp"
30 #include "jfr/leakprofiler/checkpoint/objectSampleCheckpoint.hpp"
31 #include "jfr/leakprofiler/sampling/objectSample.hpp"
32 #include "jfr/leakprofiler/sampling/objectSampler.hpp"
33 #include "logging/log.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "oops/markOop.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "runtime/thread.inline.hpp"
38 #include "runtime/vmThread.hpp"
39
40 EventEmitter::EventEmitter(const JfrTicks& start_time, const JfrTicks& end_time) :
41 _start_time(start_time),
42 _end_time(end_time),
43 _thread(Thread::current()),
44 _jfr_thread_local(_thread->jfr_thread_local()),
45 _thread_id(_thread->jfr_thread_local()->thread_id()) {}
46
47 EventEmitter::~EventEmitter() {
48 // restore / reset thread local stack trace and thread id
49 _jfr_thread_local->set_thread_id(_thread_id);
50 _jfr_thread_local->clear_cached_stack_trace();
51 }
52
53 void EventEmitter::emit(ObjectSampler* sampler, int64_t cutoff_ticks, bool emit_all) {
54 assert(sampler != NULL, "invariant");
55
56 ResourceMark rm;
57 EdgeStore edge_store;
58 if (cutoff_ticks <= 0) {
59 // no reference chains
60 JfrTicks time_stamp = JfrTicks::now();
61 EventEmitter emitter(time_stamp, time_stamp);
62 emitter.write_events(sampler, &edge_store, emit_all);
63 return;
64 }
65 // events emitted with reference chains require a safepoint operation
66 PathToGcRootsOperation op(sampler, &edge_store, cutoff_ticks, emit_all);
67 VMThread::execute(&op);
68 }
69
70 size_t EventEmitter::write_events(ObjectSampler* object_sampler, EdgeStore* edge_store, bool emit_all) {
71 assert(_thread == Thread::current(), "invariant");
72 assert(_thread->jfr_thread_local() == _jfr_thread_local, "invariant");
73 assert(object_sampler != NULL, "invariant");
74 assert(edge_store != NULL, "invariant");
75
76 const jlong last_sweep = emit_all ? max_jlong : object_sampler->last_sweep().value();
77 size_t count = 0;
78
79 const ObjectSample* current = object_sampler->first();
80 while (current != NULL) {
81 ObjectSample* prev = current->prev();
82 if (current->is_alive_and_older_than(last_sweep)) {
83 write_event(current, edge_store);
84 ++count;
85 }
86 current = prev;
87 }
88
89 if (count > 0) {
90 // serialize associated checkpoints and potential chains
91 ObjectSampleCheckpoint::write(object_sampler, edge_store, emit_all, _thread);
92 }
93 return count;
94 }
95
96 static int array_size(const oop object) {
97 assert(object != NULL, "invariant");
98 if (object->is_array()) {
99 return arrayOop(object)->length();
100 }
101 return min_jint;
102 }
103
104 void EventEmitter::write_event(const ObjectSample* sample, EdgeStore* edge_store) {
105 assert(sample != NULL, "invariant");
106 assert(!sample->is_dead(), "invariant");
107 assert(edge_store != NULL, "invariant");
108 assert(_jfr_thread_local != NULL, "invariant");
109
110 const oop* object_addr = sample->object_addr();
111 traceid gc_root_id = 0;
112 const Edge* edge = NULL;
113 if (SafepointSynchronize::is_at_safepoint()) {
114 edge = (const Edge*)(*object_addr)->mark();
115 }
116 if (edge == NULL) {
117 // In order to dump out a representation of the event
118 // even though it was not reachable / too long to reach,
119 // we need to register a top level edge for this object.
120 edge = edge_store->put(object_addr);
121 } else {
122 gc_root_id = edge_store->gc_root_id(edge);
123 }
124
125 assert(edge != NULL, "invariant");
126 const traceid object_id = edge_store->get_id(edge);
127 assert(object_id != 0, "invariant");
128
129 EventOldObjectSample e(UNTIMED);
130 e.set_starttime(_start_time);
131 e.set_endtime(_end_time);
132 e.set_allocationTime(sample->allocation_time());
133 e.set_lastKnownHeapUsage(sample->heap_used_at_last_gc());
134 e.set_object(object_id);
135 e.set_arrayElements(array_size(edge->pointee()));
136 e.set_root(gc_root_id);
137
138 // Temporarily assigning both the stack trace id and thread id
139 // onto the thread local data structure of the emitter thread (for the duration
140 // of the commit() call). This trick provides a means to override
141 // the event generation mechanism by injecting externally provided id's.
142 // At this particular location, it allows us to emit an old object event
143 // supplying information from where the actual sampling occurred.
144 _jfr_thread_local->set_cached_stack_trace_id(sample->stack_trace_id());
145 assert(sample->has_thread(), "invariant");
146 _jfr_thread_local->set_thread_id(sample->thread_id());
147 e.commit();
148 }