On Wed, Oct 20, 2010 at 6:57 AM, <span dir="ltr"><<a href="mailto:rf@q-leap.de">rf@q-leap.de</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
I don't see why you want to distinguish between "user-space" and<br>
"kernel-space" SDP. </blockquote><div><br></div><div>User-space sockets and kernel-space sockets use different code paths and thus can behave differently.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
I assume by the former you mean using libsdp<br>
together with the kernel module ib_sdp. While this method uses a syscall<br>
interface to ib_sdp rather than direct "in-kernel operations" like drbd,<br>
both methods actually use the basic code in ib_sdp.<br></blockquote><div><br></div><div>While the ib_sdp module is necessary for both cases, the code paths are still not identical. User-space SDP is by far the most common usage case, other than DRBD I know of no other kernel-space SDP consumer. The user-space SDP path is much, much better tested than the kernel-space SDP path. I highly doubt there is any regression testing done for the in-kernel SDP path between releases as it is such a fringe usage case.</div>
<div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<br>
But anyway, this discussion doesn't lead to a solution of the<br>
problem. </blockquote><div><br></div><div>It does actually, if you understand the problem: the problem being your SDP implementation not DRBD.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
In my understanding, SDP support is an advertised feature of<br>
DRBD, and I bought Infiniband hardware just because of that. All I want<br>
now is some assistance in debugging this. I believe there are a number<br>
of other users who would be happy if DRBD over SDP were working. If SDP<br>
support is not a supported feature anymore, it should be clearly stated<br>
though.</blockquote><div><br></div><div>You need a kernel with a working SDP implementation, the kernel you've chosen has a broken implementation. I've gotten SDP working with DRBD, is does work, when the Kernel has a non-broken SDP socket implementation. You're blaming the wrong piece of software for your problem if you blame DRBD.</div>
<div><br></div><div>What problem do you have with using IPoIB? Your choices are: Use IPoIB or use a different Kernel with a working kernel-space SDP implementation. You should probably contact your IB vendor for OFED support if you're dead set on using SDP instead of IPoIB.</div>
<div><br></div><div>-JR</div><div> </div></div>