On Oct 25, 2010, at 9:29 PM, George Bosilca wrote: > 1. Not all processes deadlock in btl_sm_add_procs. The process that setup the > shared memory area, is going forward, and block later in a barrier.
Yes, I'm seeing the same thing (I didn't include all details like this in my post, sorry). I was running with -np 2 on a local machine and saw vpid=0 get stuck in opal_progress (because the first time through, seg_inited < n_local_procs). vpid=1 increments seg_inited and therefore doesn't enter the loop that calls opal_progress(), and therefore continues on. > 2. All other processes, loop around the opal_progress, until they got a > message from all other processes. The variable used for counting is somehow > updated correctly, but we still call opal_progress. I couldn't figure out is > we loop more that we should, or if opal_progress doesn't return. However, > both of these possibilities look very unlikely to me: the loop in the > sm_add_procs is pretty straightforward, and I couldn't find any loops in > opal_progress. I wonder if some of the messages get lost on the exchange. I had this problem, too, until I tried to use padb to get stack traces. I noticed that when I ran padb, my blocked process un-blocked itself and continued. After more digging, I determined that my blocked process was, in fact, blocked in poll() with an infinite timeout. padb (or any signal at all) caused it to unblock and therefore continue. > 3. If I unblock the situation by hand, everything goes back to normal. > NetPIPE runs to completion but the performances are __really__ bad. On my > test machine I get around 2000Mbs, when the expected value is at least 10 > times more. Similar finding on the latency side, we're now at 1.65 micro-sec > up from the usual 0.35 we had before. It's a feature! -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
