From 88f3da8fff01c505d4d2d5524f34c12d2a09030f Mon Sep 17 00:00:00 2001 From: Jason Abele Date: Fri, 15 Jul 2011 16:26:19 -0700 Subject: Added notes on latency and through put tuning for UDP --- host/docs/transport.rst | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'host/docs/transport.rst') diff --git a/host/docs/transport.rst b/host/docs/transport.rst index e7c2f1885..f28d1efcb 100644 --- a/host/docs/transport.rst +++ b/host/docs/transport.rst @@ -38,6 +38,14 @@ increase or decrease the maximum number of samples per packet. The frame sizes default to an MTU of 1472 bytes per IP/UDP packet, and may be increased if permitted by your network hardware. +**Note3:** For lower latency at low sample rates, use smaller buffers + +**Note4:** For overall lower latency, look for Interrupt Coalescing settings +for your OS and ethernet chipset. It seems the Intel ethernet chipsets offer +fine-grained control in Linux. Also, consult: + +* http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.prftungd/doc/prftungd/interrupt_coal.htm + ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Flow control parameters ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -77,6 +85,16 @@ To change the maximum values, run the following commands: Set the values permanently by editing */etc/sysctl.conf* +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +Windows specific notes +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +On Windows, it is important to change the default UDP behavior such that +1500 byte packets still travel through the fast path of the sockets stack. + +FastSendDatagramThreshold registry key to change documented here: + +* http://www.microsoft.com/windows/windowsmedia/howto/articles/optimize_web.aspx#appendix_e + ------------------------------------------------------------------------ USB transport (libusb) ------------------------------------------------------------------------ -- cgit v1.2.3