setting size of buffers from device args

1 files changed, 35 insertions, 0 deletions

diff --git a/host/docs/usrp2.rst b/host/docs/usrp2.rst
index 092332442..f4c36fb27 100644
--- a/host/docs/usrp2.rst
+++ b/host/docs/usrp2.rst
@@ -126,3 +126,38 @@ MAC addresses, control packets, and fast-path settings.
 
 **Monitor the host network traffic:**
 Use wireshark to monitor packets sent to and received from the USRP2.
+
+------------------------------------------------------------------------
+Resize the send and receive buffers
+------------------------------------------------------------------------
+It may be useful increase the size of the socket buffers to
+move the burden of buffering samples into the kernel, or to
+buffer incoming samples faster than they can be processed.
+However, if you application cannot process samples fast enough,
+no amount of buffering can save you.
+
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Device address params
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+To set the size of the buffers,
+the usrp2 will accept two optional parameters in the device address.
+Each parameter will accept a numeric value for the number of bytes.
+
+* recv_buff_size
+* send_buff_size
+
+Example, set the args string to the following:
+::
+
+    addr=192.168.10.2, recv_buff_size=100e6
+
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+OS specific notes
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+On linux, the maximum buffer sizes are capped by the sysctl values
+**net.core.rmem_max** and **net.core.wmem_max**.
+To change the maximum values, run the following commands:
+::
+
+    sudo sysctl -w net.core.rmem_max=<new value>
+    sudo sysctl -w net.core.wmem_max=<new value>