On 04/20/2013 02:20 PM, [email protected] wrote: >> >>> -----Original Message----- >>> From: Jagdish Motwani [mailto:[email protected]] >>> Sent: Friday, April 19, 2013 2:48 AM >>> To: [email protected] >>> Subject: Re: [E1000-devel] ixgbe 82599 latency tunning >>> >>> >>> Resending the table-- trying to format it properly >>> >>> Rx ring Tx ring rx_pb_size flow control latency >>> 512 512 512 rx on tx on 7128 >>> 64 128 512 rx on tx on 6346 >>> 512 512 512 rx off tx off 1874 >>> 64 128 512 rx off tx off 667 >>> 64 128 128 rx off tx off 230 >>> 32 128 128 rx off tx off 150 >>> 16 128 128 rx off tx off 110 >> What test are you using to measure the latency? >> >> What is the latency in the above table measured in (trans/sec)? >> >> You may want to experiment with the InterruptThrottleRate parameter >> (ethtool -C ethX rx-usecs) to increase the interrupt threshold, which >> should help with latency. >> >> Thanks, >> Emil >> >> >> > I am using spirent test center for the test. Results are in micro seconds. > > I did tried Interrupt Throttling earlier but was unable to lower the latency. > To be more specific, I had tried rx-usecs 0. (All the results above are > with rx-usecs 1) > > Regards, > Jagdish Motwani Just to be more clear: I don't face any latency issue in case of normal load.
If my device can handle the traffic, latency is not more than 150 microseconds. But i face latency issue if 1) When load is too high to handle (e.g. passing 20Gbps when i can process only 1 Gbps and drop the rest) or 2) When i can handle load but it is at exact line rate (exactly 20Gbps) From the data sheets of 82599, i could make out that RXPBSIZE0 is by default 512 KB. As per me, this buffering is what causes the latency i am facing (at least for the first point). And so i modified rx_pb_size from 512 to 128. I would like to know whether i going in the right direction or not? Regards, Jagdish Motwani ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
