On 22 September 2016 at 10:29, Yuanhan Liu <yuanhan.liu at linux.intel.com> wrote: > On Wed, Sep 21, 2016 at 08:54:11PM +0800, Jianbo Liu wrote: >> >> > My setup consists of one host running a guest. >> >> > The guest generates as much 64bytes packets as possible using >> >> >> >> Have you tested with other different packet size? >> >> My testing shows that performance is dropping when packet size is more >> >> than 256. >> > >> > >> > Hi Jianbo, >> > >> > Thanks for reporting this. >> > >> > 1. Are you running the vector frontend with mrg_rxbuf=off? >> > Yes, my testing is mrg_rxbuf=off, but not vector frontend PMD.
>> > 2. Could you please specify what CPU you're running? Is it Haswell >> > or Ivy Bridge? >> > It's an ARM server. >> > 3. How many percentage of drop are you seeing? The testing result: size (bytes) improvement (%) 64 3.92 128 11.51 256 24.16 512 -13.79 1024 -22.51 1500 -12.22 A correction is that performance is dropping if byte size is larger than 512. >> > >> > This is expected by me because I've already found the root cause and >> > the way to optimize it, but since it missed the v0 deadline and >> > requires changes in eal/memcpy, I postpone it to the next release. >> > >> > After the upcoming optimization the performance for packets larger >> > than 256 will be improved, and the new code will be much faster than >> > the current code. >> > >> >> Sorry, I tested on an ARM server, but I wonder if there is the same >> issue for x86 platform. > > Would you please provide more details? Say, answer the two left > questions from Zhihong? > > Thanks. > > --yliu
