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Make sure Zygote is running at process priority 0 after VM has started.

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Boosting up zygote priority before VM startup, saves ~450ms of boot time
for N9, 180ms for Nexus 5X.

(cherry picked from commit 5d551a5ac3)

Bug: 28866384
Test: m
Test: Device boots
Change-Id: Ic85892b408e15bbc1de7ce706f113f23974fe478
This commit is contained in:
Vitalii Tomkiv
2016-05-18 17:43:02 -07:00
committed by Andreas Gampe
parent 8175f0955a
commit 1e52ce48a6
1 changed files with 21 additions and 1 deletions
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22
core/jni/com_android_internal_os_Zygote.cpp
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@@ -37,6 +37,7 @@
#include <sys/prctl.h> #include <sys/prctl.h>
#include <sys/resource.h> #include <sys/resource.h>
#include <sys/stat.h> #include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h> #include <sys/types.h>
#include <sys/utsname.h> #include <sys/utsname.h>
#include <sys/wait.h> #include <sys/wait.h>
@@ -153,6 +154,24 @@ static void SetSigChldHandler() {
} }
} }
// 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. // Sets the SIGCHLD handler back to default behavior in zygote children.
static void UnsetSigChldHandler() { static void UnsetSigChldHandler() {
struct sigaction sa; struct sigaction sa;
@@ -447,6 +466,8 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra
RuntimeAbort(env, __LINE__, "Unable to restat file descriptor table."); RuntimeAbort(env, __LINE__, "Unable to restat file descriptor table.");
} }
ResetNicePriority(env);
pid_t pid = fork(); pid_t pid = fork();
if (pid == 0) { if (pid == 0) {
@@ -719,4 +740,3 @@ int register_com_android_internal_os_Zygote(JNIEnv* env) {
return RegisterMethodsOrDie(env, "com/android/internal/os/Zygote", gMethods, NELEM(gMethods)); return RegisterMethodsOrDie(env, "com/android/internal/os/Zygote", gMethods, NELEM(gMethods));
} }
} // namespace android } // namespace android