Make use of profiling information for dex2oat
If the profile file exists, the compiler driver will read it
and store the data in an internal map. Then, when we want to work
out whether to compile a method or not, the map is consulted and if
the method shows up with a high enough percentage of use we compile it.
The profile file itself is created by installd and is writeable by the
app. The file is in /data/dalvik-cache/profiles and is named by
the package name.
This also modifies the profiler itself to:
1. Only count runnable threads (not suspended threads) in the profile
2. Use system properties to allow tuning of the profile parameters
3. Merge profiles from multiple processes using file locking.
Bug: 12877748
Change-Id: Iab2f3a327a2860db2a80d5724277d6c626227f2b
Conflicts:
compiler/dex/frontend.cc
compiler/dex/mir_analysis.cc
compiler/dex/verification_results.cc
compiler/driver/compiler_driver.cc
dex2oat/dex2oat.cc
runtime/class_linker.cc
runtime/runtime.cc
runtime/runtime.h
diff --git a/runtime/native/dalvik_system_DexFile.cc b/runtime/native/dalvik_system_DexFile.cc
index 8a96d79..bab0604 100644
--- a/runtime/native/dalvik_system_DexFile.cc
+++ b/runtime/native/dalvik_system_DexFile.cc
@@ -15,6 +15,7 @@
*/
#include <unistd.h>
+#include <fcntl.h>
#include "base/logging.h"
#include "class_linker.h"
@@ -36,6 +37,10 @@
#include "toStringArray.h"
#include "zip_archive.h"
+#ifdef HAVE_ANDROID_OS
+#include "cutils/properties.h"
+#endif
+
namespace art {
// A smart pointer that provides read-only access to a Java string's UTF chars.
@@ -193,7 +198,40 @@
return toStringArray(env, class_names);
}
-static jboolean DexFile_isDexOptNeeded(JNIEnv* env, jclass, jstring javaFilename) {
+// Copy a profile file
+static void CopyProfileFile(const char* oldfile, const char* newfile) {
+ int fd = open(oldfile, O_RDONLY);
+ if (fd < 0) {
+ // If we can't open the file show the uid:gid of the this process to allow
+ // diagnosis of the problem.
+ LOG(ERROR) << "Failed to open profile file " << oldfile<< ". My uid:gid is "
+ << getuid() << ":" << getgid();
+ return;
+ }
+
+ // Create the copy with rw------- (only accessible by system)
+ int fd2 = open(newfile, O_WRONLY|O_CREAT|O_TRUNC, 0600);
+ if (fd2 < 0) {
+ // If we can't open the file show the uid:gid of the this process to allow
+ // diagnosis of the problem.
+ LOG(ERROR) << "Failed to create/write prev profile file " << newfile << ". My uid:gid is "
+ << getuid() << ":" << getgid();
+ return;
+ }
+ char buf[4096];
+ while (true) {
+ int n = read(fd, buf, sizeof(buf));
+ if (n <= 0) {
+ break;
+ }
+ write(fd2, buf, n);
+ }
+ close(fd);
+ close(fd2);
+}
+
+static jboolean DexFile_isDexOptNeededInternal(JNIEnv* env, jclass, jstring javaFilename,
+ jstring javaPkgname, jboolean defer) {
const bool kVerboseLogging = false; // Spammy logging.
const bool kDebugLogging = true; // Logging useful for debugging.
@@ -221,6 +259,97 @@
}
}
+ // Check the profile file. We need to rerun dex2oat if the profile has changed significantly
+ // since the last time, or it's new.
+ // If the 'defer' argument is true then this will be retried later. In this case we
+ // need to make sure that the profile file copy is not made so that we will get the
+ // same result second time.
+ if (javaPkgname != NULL) {
+ ScopedUtfChars pkgname(env, javaPkgname);
+ std::string profile_file = GetDalvikCacheOrDie(GetAndroidData()) + std::string("/profiles/") +
+ pkgname.c_str();
+
+ std::string profile_cache_dir = GetDalvikCacheOrDie(GetAndroidData()) + "/profile-cache";
+
+ // Make the profile cache if it doesn't exist.
+ mkdir(profile_cache_dir.c_str(), 0700);
+
+ // The previous profile file (a copy of the profile the last time this was run) is
+ // in the dalvik-cache directory because this is owned by system. The profiles
+ // directory is owned by install so system cannot write files in there.
+ std::string prev_profile_file = profile_cache_dir + std::string("/") + pkgname.c_str();
+
+ struct stat profstat, prevstat;
+ int e1 = stat(profile_file.c_str(), &profstat);
+ int e2 = stat(prev_profile_file.c_str(), &prevstat);
+
+ if (e1 < 0) {
+ // No profile file, need to run dex2oat
+ if (kDebugLogging) {
+ LOG(INFO) << "DexFile_isDexOptNeeded profile file " << profile_file << " doesn't exist";
+ }
+ return JNI_TRUE;
+ }
+ if (e2 == 0) {
+ // There is a previous profile file. Check if the profile has changed significantly.
+ // Let's use the file size as a proxy for significance. If the new profile is 10%
+ // different in size than the the old profile then we run dex2oat.
+ double newsize = profstat.st_size;
+ double oldsize = prevstat.st_size;
+ bool need_profile = false;
+
+ double ratio = 0; // If the old file was empty and the new one not
+ if (oldsize > 0 && newsize > 0) {
+ ratio = newsize / oldsize;
+ } else if (oldsize == 0 && newsize > 0) {
+ need_profile = true;
+ } else if (oldsize > 0 && newsize == 0) {
+ // Unlikely to happen, but cover all the bases.
+ need_profile = true;
+ }
+
+ double significant_difference = 10.0;
+#ifdef HAVE_ANDROID_OS
+ // Switch off profiler if the dalvik.vm.profiler property has value 0.
+ char buf[PROP_VALUE_MAX];
+ property_get("dalvik.vm.profiler.dex2oat.threshold", buf, "10.0");
+ significant_difference = strtod(buf, nullptr);
+
+ // Something reasonable?
+ if (significant_difference < 1.0 || significant_difference > 90.0) {
+ significant_difference = 10.0;
+ }
+#endif // The percentage difference that we consider as being significant.
+ double diff_hwm = 1.0 + significant_difference/10.0;
+ double diff_lwm = 1.0 - significant_difference/10.0;
+
+ if (ratio > diff_hwm || ratio < diff_lwm) {
+ need_profile = true;
+ }
+
+ if (need_profile) {
+ if (kDebugLogging) {
+ LOG(INFO) << "DexFile_isDexOptNeeded size of new profile file " << profile_file <<
+ " is significantly different from old profile file " << prev_profile_file << " (new: " <<
+ newsize << ", old: " << oldsize << ", ratio: " << ratio << ")";
+ }
+ if (!defer) {
+ CopyProfileFile(profile_file.c_str(), prev_profile_file.c_str());
+ }
+ return JNI_TRUE;
+ }
+ } else {
+ // Previous profile does not exist. Make a copy of the current one.
+ if (kDebugLogging) {
+ LOG(INFO) << "DexFile_isDexOptNeeded previous profile doesn't exist: " << prev_profile_file;
+ }
+ if (!defer) {
+ CopyProfileFile(profile_file.c_str(), prev_profile_file.c_str());
+ }
+ return JNI_TRUE;
+ }
+ }
+
// Check if we have an odex file next to the dex file.
std::string odex_filename(OatFile::DexFilenameToOdexFilename(filename.c_str()));
std::string error_msg;
@@ -329,11 +458,18 @@
return JNI_FALSE;
}
+// public API, NULL pkgname
+static jboolean DexFile_isDexOptNeeded(JNIEnv* env, jclass c, jstring javaFilename) {
+ return DexFile_isDexOptNeededInternal(env, c, javaFilename, NULL, false);
+}
+
+
static JNINativeMethod gMethods[] = {
NATIVE_METHOD(DexFile, closeDexFile, "(J)V"),
NATIVE_METHOD(DexFile, defineClassNative, "(Ljava/lang/String;Ljava/lang/ClassLoader;J)Ljava/lang/Class;"),
NATIVE_METHOD(DexFile, getClassNameList, "(J)[Ljava/lang/String;"),
NATIVE_METHOD(DexFile, isDexOptNeeded, "(Ljava/lang/String;)Z"),
+ NATIVE_METHOD(DexFile, isDexOptNeededInternal, "(Ljava/lang/String;Ljava/lang/String;Z)Z"),
NATIVE_METHOD(DexFile, openDexFileNative, "(Ljava/lang/String;Ljava/lang/String;I)J"),
};