Read the source. A multi-segment mbuf has the first mbuf with nb_segs > 1 and chained by next pointer. It is a bug in the creator of the mbuf, if number of segments and next chain don't match.
There is a rte_pktmbuf_dump(), you can use to look at how your mbuf is formatted. On Tue, Mar 22, 2016 at 1:36 PM, Clarylin L <clearasu at gmail.com> wrote: > Sorry my bad. The mbuf size has been accidentally changed to 3000. > > After fixing this by setting mbuf size to 2048, multi-segment mbuf still > doesn't work. I was trying to send 2500-byte packets to the target system > and was expecting to see two-segment mbuf chain), but got errors on it. > > Tue Mar 22 14:52:00 2016^@PMD: rte_enic_pmd: packet error > > > Tue Mar 22 14:52:01 2016^@PMD: rte_enic_pmd: packet error > > > Tue Mar 22 14:52:02 2016^@PMD: rte_enic_pmd: packet error > > > Tue Mar 22 14:52:03 2016^@PMD: rte_enic_pmd: packet error > > > Tue Mar 22 14:52:04 2016^@PMD: rte_enic_pmd: packet error > > > Is enic supporting multi-segment mbuf? The dpdk version is 2.0.0. I have > enabled jumbo-frame and enable_scatter for the port. > > On Tue, Mar 22, 2016 at 3:27 AM, Bruce Richardson < > bruce.richardson at intel.com> wrote: > > > On Mon, Mar 21, 2016 at 04:34:50PM -0700, Clarylin L wrote: > > > I am trying multi-segment mbuf, but it seems not working. > > > > > > On my target host, the mbuf size is set to 2048 and I am trying to send > > > large packet to it (say 2500 bytes without fragmentation) from another > > > host. I enabled both jumbo_frame and enable_scatter for the port. But I > > saw > > > on the target only one mbuf is received with data_len equal to 2500 > (it's > > > supposed to be a two-mbuf chain). Although mbuf itself is not working > as > > > expected, ping between two hosts succeeded (large ping size; no > > > fragmentation). > > > > > > 1. my mbuf size is only 2048. how can it support receiving such large > > > packet in one mbuf? > > > > > > 2.how to make it work as expected (enable multi-segment mbuf and > receive > > > using mbuf chain when needed)? > > > > > > Appreciate your help. > > > > Hi, > > > > when you get the single mbuf with data_len == 2500, what is the buf_len > > value > > reported as? > > > > /Bruce > > >
