On 08/25/2015 08:52 PM, Vlad Zolotarov wrote: > > Helin, the issue has been seen on x540 devices. Pls., see a chapter > 7.2.1.1 of x540 devices spec: > > A packet (or multiple packets in transmit segmentation) can span any > number of > buffers (and their descriptors) up to a limit of 40 minus WTHRESH > minus 2 (see > Section 7.2.3.3 for Tx Ring details and section Section 7.2.3.5.1 for > WTHRESH > details). For best performance it is recommended to minimize the > number of buffers > as possible. > > Could u, pls., clarify why do u think that the maximum number of data > buffers is limited by 8? > > thanks, > vlad
Hi vlad, Documentation states that a packet (or multiple packets in transmit segmentation) can span any number of buffers (and their descriptors) up to a limit of 40 minus WTHRESH minus 2. Shouldn't there be a test in transmit function that drops properly the mbufs with a too large number of segments, while incrementing a statistic; otherwise transmit function may be locked by the faulty packet without notification. thanks didier
