On Mon, Apr 29, 2013 at 10:52:21PM +0300, Or Gerlitz wrote: > On Fri, Apr 26, 2013 at 12:40 AM, Jason Gunthorpe wrote: > > But I don't follow why the send QPNs have to be sequential for > > IPoIB. It looks like this is being motivated by RSS and RSS QPNs are > > just being reused for TSS? > > Go read "It turns out that there are IPoIB drivers used by some > operating-systems > and/or Hypervisors in a para-virtualization (PV) scheme which extract the > source QPN from the CQ WC associated with an incoming packets in order > to.." and what follows in the change-log of patch 4/5 > http://marc.info/?l=linux-rdma&m=136412901621797&w=2
This is what I said in the first place, the RFC is premised on the src.QPN to be set properly, you can't just mess with it, because stuff needs it. I think you should have split this patch up, there is lots going on here. - Add proper TSS that doesn't change the wire protocol - Add fake TSS that does change the wire protocol, and properly document those changes so other people can follow/implement them - Add RSS And.. 'tss_qpn_mask_sz' seems unnecessarily limiting, using WC.srcQPN + ipoib_header.tss_qpn_offset == real QPN (ie use a signed offset, not a mask) Seems much better than Wc.srcQPN & ~((1<<(ipoib_header.tss_qpn_mask_sz >> 12))-1) == real QPN (Did I even get that right?) Specifically it means the requirements for alignment and contiguous-ness are gone. This means you can implement it without using the QP groups API and it will work immediately with every HCA out there. I think if we are going to actually mess with the wire protocol this sort of broad applicability is important. As for the other two questions: seems reasonable to me. Without a consensus among HW vendors how to do this it makes sense to move ahead *in the kernel* with a minimal API. Userspace is a different question of course.. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
