On 01/28/2014 12:00 AM, Michael Quicquaro wrote: > 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 >
Thanks for confirming my guesses! By the way, make sure the number of packets you receive in a single burst is less than configured queue size. Or you will lose packets too. Maybe your "small" delay in not so small :) For my own purposes I use a delay of about 150usecs. P.S. I wonder why this issue is not mentioned in documentation. Is it evident for everyone doing network programming? > > On Wed, Jan 22, 2014 at 9:52 AM, Dmitry Vyal <dmitryvyal at gmail.com > <mailto: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 > > >
