Hi Rafael and Akihiro -- It sounds as though there isn't a known issue w.r.t. large ibv conduit messages (I didn't catch the importance of 'strided', so sent that along in a second message, but don't expect it'll change the response). They wrote:
> We don't have a known error with long messages, but do have one with > respect to free() which might be the problem. If we (ibv-conduit via > firehose) cache a dynamic memory registration (especially problematic w/ > SEGENT_EVERYTHING), then it is possible that memory is free()d and a > later malloc() gets the same virtual address. If that happens then ibv > may end up performing RDMA from the physical pages corresponding to the > PREVIOUS association for the virtual address (NOTE: the pages are > ref-counted and thus NOT truly free and NOT mapped into some other > process). See https://upc-bugs.lbl.gov/bugzilla/show_bug.cgi?id=495 for > some details on that bug. The work-arounds are to disable mmap-based > malloc(), or disable firehose. To me, this doesn't sound like the same thing, but I'm far enough away from the problem that you may recognize something that I'm not. Assuming it doesn't, how hard would it be to put together a small C+GASnet test that exhibits this issue? Would it be as simple as sending a large buffer in strided mode? In a loop? As long as I was bothering them, I also asked whether there was a way to sanity check that an executable was built with debugging on (since there are so many ways that we could get this wrong) and got the response: > As for checking for debugging support, the preprocessor token > GASNET_CONFIG_STRING will tell you a lot about the configuration you've > compiled with. We do some name-shifting to ensure you can't link with a > library of a different configuration that you've compiled with. > > Alternatively if you have the "ident" utility for finding RCS strings, > applying it to the executable file will extract lots of configuration > bits. The value of GASNET_CONFIG_STRING will follow "$GASNetConfig:" > You can fake that with: > $ perl -n -ln044 -e 'print if /GASNetConfig:/' -- a.out Thanks, -Brad ------------------------------------------------------------------------------ WatchGuard Dimension instantly turns raw network data into actionable security intelligence. It gives you real-time visual feedback on key security issues and trends. Skip the complicated setup - simply import a virtual appliance and go from zero to informed in seconds. http://pubads.g.doubleclick.net/gampad/clk?id=123612991&iu=/4140/ostg.clktrk _______________________________________________ Chapel-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/chapel-developers
