commit d98f4e8af5076e6a9dbd4ddc2c375cb7bcda8cd8
author Riley Andrews <riandrews@google.com> Mon Jun 08 23:36:34 2015 -0700
committer Riley Andrews <riandrews@google.com> Tue Jun 09 12:36:45 2015 -0700
tree 0612af9c0104dc2df0b235822e6651eb45430154
parent 6f1457adc58644f7c68829fd0872947bd7e63bfd

Lower the priority of the threads in logd/logcat.

sched_batch implies only a penalty to latency in scheduling, but
does not imply that the process will be given less cpu time. Increase
the nice level to 10 to prioritize it below ui threads.

Bug: 21696721
Change-Id: I075af059dc755402f7df9b0d7a66cca921ff04b2

logcat/logcat.cpp

diff --git a/logcat/logcat.cpp b/logcat/logcat.cpp
index 736e02e..e598bb8 100644
--- a/logcat/logcat.cpp
+++ b/logcat/logcat.cpp
@@ -14,6 +14,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/cdefs.h>
+#include <sys/resource.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -33,6 +34,7 @@
 #include <log/logd.h>
 #include <log/logger.h>
 #include <log/logprint.h>
+#include <utils/threads.h>
 
 #define DEFAULT_MAX_ROTATED_LOGS 4
 
@@ -221,6 +223,10 @@
             fprintf(stderr, "failed to set to batch scheduler\n");
         }
 
+        if (setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND) < 0) {
+            fprintf(stderr, "failed set to priority\n");
+        }
+
         g_outFD = openLogFile (g_outputFileName);
 
         if (g_outFD < 0) {

logd/main.cpp

diff --git a/logd/main.cpp b/logd/main.cpp
index 6db819e..47f11fb 100644
--- a/logd/main.cpp
+++ b/logd/main.cpp
@@ -27,6 +27,7 @@
 #include <sys/capability.h>
 #include <sys/klog.h>
 #include <sys/prctl.h>
+#include <sys/resource.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <syslog.h>
@@ -37,6 +38,7 @@
 #include <cutils/sockets.h>
 #include <log/event_tag_map.h>
 #include <private/android_filesystem_config.h>
+#include <utils/threads.h>
 
 #include "CommandListener.h"
 #include "LogBuffer.h"
@@ -91,6 +93,10 @@
         return -1;
     }
 
+    if (setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND) < 0) {
+        return -1;
+    }
+
     if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
         return -1;
     }
@@ -156,6 +162,7 @@
 static void *reinit_thread_start(void * /*obj*/) {
     prctl(PR_SET_NAME, "logd.daemon");
     set_sched_policy(0, SP_BACKGROUND);
+    setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND);
 
     setgid(AID_SYSTEM);
     setuid(AID_SYSTEM);