On Mon, Aug 05, 2013 at 04:34:17PM +0000, Robert Osfield wrote: > HI David, > > I have my brain focused on some big topics today without much scope > with thinking other complicated areas so won't dive into this one > right now. > > I recall a discussion about thread safety of Notify from last year > with a user who was heavily using notification in a multi-threaded > environement and found issues like yourself, I don't know if they are > the same though,I don't recall the details. He may of submitted > changes or proposed some, but if they had been straight forward and > without a performance compromise I would have merged them. It might > be searching the archives on osg-users and osg-submissions to look at > the discussions, it might help. I did merge some changes w.r.t > threading though:
Date: Nov 28 06:08:02 2011 From: George Bekos <bekos...@live.com> Subject: [osg-users] Custom osg::NotifyHandler problems and multi-threading It sounded like the same issue, no changes were posted on the thread. It sounded to me to show an example that reproduced it on Linux which is what I posted. For now we'll just make sure are logging levels are set low so we don't have much chance of hitting it. > r13094 | robert | 2012-06-22 16:21:08 +0000 (Fri, 22 Jun 2012) | 2 lines > > Restructed the way that the global notify variables are initialized to > avoid problems with multi-threaded initialization of these variables. > > This is at start up though. As for the assumptions that cerr and cout > are thread safe, normally I'd stick with this assumption, but I'm not > sure it's always the case across all compilers etc. > > Robert. > > On 5 August 2013 16:10, David Fries <da...@fries.net> wrote: > > Hi Robert, > > > > I tested against the svn 3.2 and trunk branches today on Linux and get > > the same results with the test program I posted. > > > > ./ThreadedNotify 48 10000000 2 2 > > Segmentation fault > > ./ThreadedNotify 48 10000000 2 2 > > *** glibc detected *** ./ThreadedNotify: free(): invalid pointer: > > 0x0000000000d81500 *** > > Segmentation fault > > ./ThreadedNotify 48 10000000 2 2 > > *** glibc detected *** ./ThreadedNotify: double free or corruption (!prev): > > 0x000000000189b500 *** > > Segmentation fault > > > > On Sun, Aug 04, 2013 at 11:48:56AM +0000, Robert Osfield wrote: > >> Hi David, > >> > >> There were various changes to osg::Notify during the 3.1.x dev cycle. > >> Could you try out OSG-3.2 and see how you get on. > >> > >> Robert. > >> > >> On 2 August 2013 22:54, David Fries <da...@fries.net> wrote: > >> > I spent a few days tracking down a crash I was having generally when a > >> > terrapage terrain was paging. This is using OSG 3.1, when I finally > >> > caught the corruption I found that both the DatabasePager thread and > >> > the Draw thread were calling OSG_NOTIFY. > >> > > >> > I wrote up a test that does little more than start up a bunch of > >> > threads and print messages and found it too crashes. I am testing on > >> > both Linux x86-64 gcc 4.7.2, and Windows 7 Visual Studio 10 and both > >> > crash, though it crashes much quicker on Windows. > >> > > >> > It will crash pretty quickly with the default (no arguments) on Windows. > >> > > >> > The following arguments are working for me to crash on Linux on a 12 > >> > core (24 with hyperthreading), x86-64 system. > >> > ./ThreadedNotify 48 10000000 2 2 > >> > > >> > It has been pointed out that cout/cerr are thread safe, so it should > >> > be possible to make osg::notify thread safe as well. In this program > >> > it helps when I reduce the notification level, at least with the low > >> > number of messages being printed it seems to be unlikely. > >> > > >> > -- > >> > David Fries <da...@fries.net> PGP pub CB1EE8F0 > >> > http://fries.net/~david/ > >> > > >> > _______________________________________________ > >> > osg-users mailing list > >> > osg-users@lists.openscenegraph.org > >> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >> > > >> _______________________________________________ > >> osg-users mailing list > >> osg-users@lists.openscenegraph.org > >> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > -- > > David Fries <da...@fries.net> PGP pub CB1EE8F0 > > http://fries.net/~david/ > > _______________________________________________ > > osg-users mailing list > > osg-users@lists.openscenegraph.org > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org -- David Fries <da...@fries.net> PGP pub CB1EE8F0 http://fries.net/~david/ _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
