commit 3de4bb966bea192ef999b5c2154e5d91d4fab513
author Riley Andrews <riandrews@google.com> Mon Jun 08 23:36:34 2015 -0700
committer Mark Salyzyn <salyzyn@google.com> Tue Jun 09 12:40:20 2015 -0700
tree 6a45725e574ffabbdad7b9337a9ea8fd24a5e834
parent fcfc798b6f59ec873efc2bf00b5555ec51eec2ce

Lower the priority of the threads in logd/logcat.

(cherry pick from commit 98b580b4857f81fc32e9e84954704ee0278029b1)

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 805cbe6..a876c99 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);