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Commit 5d551a5a authored by Vitalii Tomkiv's avatar Vitalii Tomkiv
Browse files

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.

Bug: 28866384

Change-Id: Ic85892b408e15bbc1de7ce706f113f23974fe478
parent dce22f04

core/jni/com_android_internal_os_Zygote.cpp

+21 −1
Original line number Original line Diff line number Diff line
@@ -36,6 +36,7 @@ 
#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>
@@ -151,6 +152,24 @@ 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;
@@ -448,6 +467,8 @@ static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArra 
  SetForkLoad(true);

  SetForkLoad(true);

#endif

#endif





  ResetNicePriority(env);



  pid_t pid = fork();

  pid_t pid = fork();





  if (pid == 0) {

  if (pid == 0) {
@@ -692,4 +713,3 @@ 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