Dmitry, I cannot thank you enough for this information. This too was my main problem. I put a "small" unmeasured delay before the call to rte_eth_rx_burst() and suddenly it starts returning bursts of 512 packets vs. 4!! Best Regards, Mike
On Wed, Jan 22, 2014 at 9:52 AM, Dmitry Vyal <dmitryvyal at gmail.com> wrote: > Hello MIchael, > > I suggest you to check average burst sizes on receive queues. Looks like I > stumbled upon a similar issue several times. If you are calling > rte_eth_rx_burst too frequently, NIC begins losing packets no matter how > many CPU horse power you have (more you have, more it loses, actually). In > my case this situation occured when average burst size is less than 20 > packets or so. I'm not sure what's the reason for this behavior, but I > observed it on several applications on Intel 82599 10Gb cards. > > Regards, Dmitry > > > > On 01/09/2014 11:28 PM, Michael Quicquaro wrote: > >> Hello, >> My hardware is a Dell PowerEdge R820: >> 4x Intel Xeon E5-4620 2.20GHz 8 core >> 16GB RDIMM 1333 MHz Dual Rank, x4 - Quantity 16 >> Intel X520 DP 10Gb DA/SFP+ >> >> So in summary 32 cores @ 2.20GHz and 256GB RAM >> >> ... plenty of horsepower. >> >> I've reserved 16 1GB Hugepages >> >> I am configuring only one interface and using testpmd in rx_only mode to >> first see if I can receive at line rate. >> >> I am generating traffic on a different system which is running the netmap >> pkt-gen program - generating 64 byte packets at close to line rate. >> >> I am only able to receive approx. 75% of line rate and I see the Rx-errors >> in the port stats going up proportionally. >> I have verified that all receive queues are being used, but strangely >> enough, it doesn't matter how many queues more than 2 that I use, the >> throughput is the same. I have verified with 'mpstat -P ALL' that all >> specified cores are used. The utilization of each core is only roughly >> 25%. >> >> Here is my command line: >> testpmd -c 0xffffffff -n 4 -- --nb-ports=1 --coremask=0xfffffffe >> --nb-cores=8 --rxd=2048 --txd=2048 --mbcache=512 --burst=512 --rxq=8 >> --txq=8 --interactive >> >> What can I do to trace down this problem? It seems very similar to a >> thread on this list back in May titled "Best example for showing >> throughput?" where no resolution was ever mentioned in the thread. >> >> Thanks for any help. >> - Michael >> > >
