Add binder transaction size tracing

As binder transaction latency depends heavily on message size, it's
useful to trace the sizes as well.

I'll submit a change to catapult (systrace visualizer) to add the size
information to the binder transaction events as well.

Test: ran systrace.py ... binder_driver, looked at captured data
Test: mm in $ANDROID_BUILD_TOP
Bug: 78137932
Change-Id: I07774ac6664b03d9ebc563723831d84313821eb0
diff --git a/cmds/atrace/atrace.cpp b/cmds/atrace/atrace.cpp
index 5d21f6a..bce8b45 100644
--- a/cmds/atrace/atrace.cpp
+++ b/cmds/atrace/atrace.cpp
@@ -205,6 +205,7 @@
     { "binder_driver", "Binder Kernel driver", 0, {
         { REQ,      "events/binder/binder_transaction/enable" },
         { REQ,      "events/binder/binder_transaction_received/enable" },
+        { REQ,      "events/binder/binder_transaction_alloc_buf/enable" },
         { OPT,      "events/binder/binder_set_priority/enable" },
     } },
     { "binder_lock", "Binder global lock trace", 0, {
diff --git a/cmds/atrace/atrace.rc b/cmds/atrace/atrace.rc
index 406f909..e978322 100644
--- a/cmds/atrace/atrace.rc
+++ b/cmds/atrace/atrace.rc
@@ -55,6 +55,8 @@
     chmod 0666 /sys/kernel/tracing/events/binder/binder_transaction/enable
     chmod 0666 /sys/kernel/debug/tracing/events/binder/binder_transaction_received/enable
     chmod 0666 /sys/kernel/tracing/events/binder/binder_transaction_received/enable
+    chmod 0666 /sys/kernel/debug/tracing/events/binder/binder_transaction_alloc_buf/enable
+    chmod 0666 /sys/kernel/tracing/events/binder/binder_transaction_alloc_buf/enable
     chmod 0666 /sys/kernel/debug/tracing/events/binder/binder_lock/enable
     chmod 0666 /sys/kernel/tracing/events/binder/binder_lock/enable
     chmod 0666 /sys/kernel/debug/tracing/events/binder/binder_locked/enable