Save jit profiling info to file.
Currently saves only the hot method references and omits the inline
cache.
Change-Id: I79e91f855f6b52dc19a9a86662604f2eee16613c
diff --git a/runtime/jit/offline_profiling_info.cc b/runtime/jit/offline_profiling_info.cc
new file mode 100644
index 0000000..4450653
--- /dev/null
+++ b/runtime/jit/offline_profiling_info.cc
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "offline_profiling_info.h"
+
+#include <fstream>
+#include <set>
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
+
+#include "art_method-inl.h"
+#include "base/mutex.h"
+#include "jit/profiling_info.h"
+#include "safe_map.h"
+#include "utils.h"
+
+namespace art {
+
+// An arbitrary value to throttle save requests. Set to 500ms for now.
+static constexpr const uint64_t kMilisecondsToNano = 1000000;
+static constexpr const uint64_t kMinimumTimeBetweenSavesNs = 500 * kMilisecondsToNano;
+
+bool OfflineProfilingInfo::NeedsSaving(uint64_t last_update_time_ns) const {
+ return last_update_time_ns - last_update_time_ns_.LoadRelaxed() > kMinimumTimeBetweenSavesNs;
+}
+
+void OfflineProfilingInfo::SaveProfilingInfo(const std::string& filename,
+ uint64_t last_update_time_ns,
+ const std::set<ArtMethod*>& methods) {
+ if (!NeedsSaving(last_update_time_ns)) {
+ VLOG(profiler) << "No need to saved profile info to " << filename;
+ return;
+ }
+
+ if (methods.empty()) {
+ VLOG(profiler) << "No info to save to " << filename;
+ return;
+ }
+
+ DexFileToMethodsMap info;
+ {
+ ScopedObjectAccess soa(Thread::Current());
+ for (auto it = methods.begin(); it != methods.end(); it++) {
+ AddMethodInfo(*it, &info);
+ }
+ }
+
+ // This doesn't need locking because we are trying to lock the file for exclusive
+ // access and fail immediately if we can't.
+ if (Serialize(filename, info)) {
+ last_update_time_ns_.StoreRelaxed(last_update_time_ns);
+ VLOG(profiler) << "Successfully saved profile info to "
+ << filename << " with time stamp: " << last_update_time_ns;
+ }
+}
+
+
+void OfflineProfilingInfo::AddMethodInfo(ArtMethod* method, DexFileToMethodsMap* info) {
+ DCHECK(method != nullptr);
+ const DexFile* dex_file = method->GetDexFile();
+
+ auto info_it = info->find(dex_file);
+ if (info_it == info->end()) {
+ info_it = info->Put(dex_file, std::set<uint32_t>());
+ }
+ info_it->second.insert(method->GetDexMethodIndex());
+}
+
+static int OpenOrCreateFile(const std::string& filename) {
+ // TODO(calin) allow the shared uid of the app to access the file.
+ int fd = open(filename.c_str(),
+ O_CREAT | O_WRONLY | O_TRUNC | O_NOFOLLOW | O_CLOEXEC,
+ S_IRUSR | S_IWUSR);
+ if (fd < 0) {
+ PLOG(WARNING) << "Failed to open profile file " << filename;
+ return -1;
+ }
+
+ // Lock the file for exclusive access but don't wait if we can't lock it.
+ int err = flock(fd, LOCK_EX | LOCK_NB);
+ if (err < 0) {
+ PLOG(WARNING) << "Failed to lock profile file " << filename;
+ return -1;
+ }
+
+ return fd;
+}
+
+static bool CloseDescriptorForFile(int fd, const std::string& filename) {
+ // Now unlock the file, allowing another process in.
+ int err = flock(fd, LOCK_UN);
+ if (err < 0) {
+ PLOG(WARNING) << "Failed to unlock profile file " << filename;
+ return false;
+ }
+
+ // Done, close the file.
+ err = ::close(fd);
+ if (err < 0) {
+ PLOG(WARNING) << "Failed to close descriptor for profile file" << filename;
+ return false;
+ }
+
+ return true;
+}
+
+static void WriteToFile(int fd, const std::ostringstream& os) {
+ std::string data(os.str());
+ const char *p = data.c_str();
+ size_t length = data.length();
+ do {
+ int n = ::write(fd, p, length);
+ p += n;
+ length -= n;
+ } while (length > 0);
+}
+
+static constexpr char kFieldSeparator = ',';
+static constexpr char kLineSeparator = '\n';
+
+/**
+ * Serialization format:
+ * multidex_suffix1,dex_location_checksum1,method_id11,method_id12...
+ * multidex_suffix2,dex_location_checksum2,method_id21,method_id22...
+ * e.g.
+ * ,131232145,11,23,454,54 -> this is the first dex file, it has no multidex suffix
+ * :classes5.dex,218490184,39,13,49,1 -> this is the fifth dex file.
+ **/
+bool OfflineProfilingInfo::Serialize(const std::string& filename,
+ const DexFileToMethodsMap& info) const {
+ int fd = OpenOrCreateFile(filename);
+ if (fd == -1) {
+ return false;
+ }
+
+ // TODO(calin): Merge with a previous existing profile.
+ // TODO(calin): Profile this and see how much memory it takes. If too much,
+ // write to file directly.
+ std::ostringstream os;
+ for (auto it : info) {
+ const DexFile* dex_file = it.first;
+ const std::set<uint32_t>& method_dex_ids = it.second;
+
+ os << DexFile::GetMultiDexSuffix(dex_file->GetLocation())
+ << kFieldSeparator
+ << dex_file->GetLocationChecksum();
+ for (auto method_it : method_dex_ids) {
+ os << kFieldSeparator << method_it;
+ }
+ os << kLineSeparator;
+ }
+
+ WriteToFile(fd, os);
+
+ return CloseDescriptorForFile(fd, filename);
+}
+} // namespace art