Increase size of the the adb packets sent over the wire
The reason behing this change is to increase the adb push/pull speed
with reduceing the number of packets sent between the host and the
device because the communication is heavily bound by packet latency.
The change maintains two way compatibility in the communication
protocol with negotiating a packet size between the target and the
host with the CONNECT packets.
After this change the push/pull speeds improved significantly
(measured from Linux-x86_64 with 100MB of data):
| Old push | Old pull || New push | New pull |
-----------------------------------------------------------
Hammerhead | 4.6 MB/s | 3.9 MB/s || 13.1 MB/s | 16.5 MB/s |
-----------------------------------------------------------
Volantis | 6.0 MB/s | 6.2 MS/s || 25.9 MB/s | 29.0 MB/s |
-----------------------------------------------------------
Fugu | 6.0 MB/s | 5.1 MB/s || 27.9 MB/s | 33.2 MB/s |
-----------------------------------------------------------
Change-Id: Id9625de31266e43394289e325c7e7e473379c5d8
diff --git a/adb/protocol.txt b/adb/protocol.txt
index 333e7e7..5c7c6ba 100644
--- a/adb/protocol.txt
+++ b/adb/protocol.txt
@@ -60,11 +60,14 @@
declares the maximum message body size that the remote system
is willing to accept.
-Currently, version=0x01000000 and maxdata=4096
+Currently, version=0x01000000 and maxdata=256*1024. Older versions of adb
+hard-coded maxdata=4096, so CONNECT and AUTH packets sent to a device must not
+be larger than that because they're sent before the CONNECT from the device
+that tells the adb server what maxdata the device can support.
Both sides send a CONNECT message when the connection between them is
established. Until a CONNECT message is received no other messages may
-be sent. Any messages received before a CONNECT message MUST be ignored.
+be sent. Any messages received before a CONNECT message MUST be ignored.
If a CONNECT message is received with an unknown version or insufficiently
large maxdata value, the connection with the other side must be closed.