On Wed, Feb 26, 2014 at 12:40 AM, Jiri Kosina <jkos...@suse.cz> wrote: > On Wed, 26 Feb 2014, Or Gerlitz wrote: > >>>> And what happens if you use IPoIB datagram mode, is/why the patch is >>>> needed there?
>>> I admittedly am no infiniband expert, but my understanding is that in >>> principle Connected/Datagram mode is about MTU and checksum >>> offloading >> yes, the differences between the mode relate to these aspects, however > Thanks for confirming Still, even if different, I still don't see why not use datagram mode if the problem hits you only for connected mode. E.g datagram mode supports LSO/GRO and TX/RX checksum offloads which should cover on the smaller MTU vs. connected mode >> > but the TX path is the same. Please correct me if I am wrong. >> no, note that your patch only touched drivers/infiniband/ulp/ipoib/ipoib_cm.c >> which is basically compiled out if you set CONFIG_INFINIBAND_IPOIB_CM, >> so surely the TX path for the datagram vs. connected modes are >> different. > Yes, but for datagram mode, the tx_ring is allocated in a completely > different way (not from kworker), so this might be a non-issue, right? I > will have to look into it more deeply to be really sure; if you can > provide your insight, that'd be helpful. Note that even when operating in connected mode, the ipoib net-device instance can speak in datagram mode with remote nodes who don't support connected mor and/or when sending multicast -- specifically ipoib_dev_init() does the setup of the TX ring. Maybe you can just try this out and see if it works? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
