Make sure Zygote is running at process priority 0 after VM has started.
Boosting up zygote priority before VM startup, saves ~450ms of boot time
for N9, 180ms for Nexus 5X.
(cherry picked from commit 5d551a5ac3d13706f62a86842ff6851e1d25213b)
Bug: 28866384
Test: m
Test: Device boots
Change-Id: Ic85892b408e15bbc1de7ce706f113f23974fe478
diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp
index 894e104..39cd6e5 100644
--- a/core/jni/com_android_internal_os_Zygote.cpp
+++ b/core/jni/com_android_internal_os_Zygote.cpp
@@ -37,6 +37,7 @@
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/stat.h>
+#include <sys/time.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <sys/wait.h>
@@ -153,6 +154,24 @@
}
}
+// Resets nice priority for zygote process. Zygote priority can be set
+// to high value during boot phase to speed it up. We want to ensure
+// zygote is running at normal priority before childs are forked from it.
+//
+// This ends up being called repeatedly before each fork(), but there's
+// no real harm in that.
+static void ResetNicePriority(JNIEnv* env) {
+ errno = 0;
+ int prio = getpriority(PRIO_PROCESS, 0);
+ if (prio == -1 && errno != 0) {
+ ALOGW("getpriority failed: %s\n", strerror(errno));
+ }
+ if (prio != 0 && setpriority(PRIO_PROCESS, 0, 0) != 0) {
+ ALOGE("setpriority(%d, 0, 0) failed: %s", PRIO_PROCESS, strerror(errno));
+ RuntimeAbort(env, __LINE__, "setpriority failed");
+ }
+}
+
// Sets the SIGCHLD handler back to default behavior in zygote children.
static void UnsetSigChldHandler() {
struct sigaction sa;
@@ -486,6 +505,8 @@
RuntimeAbort(env, __LINE__, "Unable to restat file descriptor table.");
}
+ ResetNicePriority(env);
+
pid_t pid = fork();
if (pid == 0) {
@@ -774,4 +795,3 @@
return RegisterMethodsOrDie(env, "com/android/internal/os/Zygote", gMethods, NELEM(gMethods));
}
} // namespace android
-