[osg-users] Osg and threads
Hi all, Currently working on a way to manage the memory efficiently, I would like to know what are the osg threads running ? I mean there are some threads in the databasePager, depending on the rendering threading mode there are threads for the render, the cull, or whatever... Did I miss something important ? What are the osg threads ? I would like to be able to make some king of pause on all treads to be able to allocate the whole available memory for the process without having some crash because a thread would be working (and so allocating memory) during this operation. Thanks for your help. Regards, Vincent. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Osg and threads
Hi Robert, First of all thanks for your answer, I didn't know about the Viewer::startThreading/stopThreading() and this sounds interesting I know that my request seems to be a very strange way to manage memory by pausing threads ... But I am not (completely) crazy. The datas amount I have to manage is the reason why I need to be sure, before loading a file, that I have enought memory including a fixed amount that I reserve for the rest of the code... so I need to saturate memory for a little while to be sure of the amount I can use, and for that I need to stop other threads to be sure they won't crash because of bad_alloc errors that are not managed. Thanks, I'll have a look at the things you gave to me. Regards, Vincent. Le 13/01/2011 11:32, Robert Osfield a écrit : Hi Vincent, The OSG threads that will run automatically are the DatabasePager when you have paged databases and any viewer threads. There is a viewer method for getting the threads. However, the threads are designed to be arbitrarily paused, you can start and stop the viewer threads via Viewer::startThreading/stopThreading() but this creates and destroys threads so not quite what you are after. However, I'm kinda perplexed how you think you might be managing memory more efficiently by pausing threads and doing stuff and then un pausing. I can't help but feel that you need to take a step back and work out what you mean by managing memory efficiently, there are lots of different ways of doing this, but given no information about what you mean and you actual motivation for this others like myself can't really point you in the right direction, the best I can say is from the sound of it you are currently looking in the wrong place. Robert. On Thu, Jan 13, 2011 at 8:14 AM, Vincent Bourdier vincent.bourd...@gmail.com wrote: Hi all, Currently working on a way to manage the memory efficiently, I would like to know what are the osg threads running ? I mean there are some threads in the databasePager, depending on the rendering threading mode there are threads for the render, the cull, or whatever... Did I miss something important ? What are the osg threads ? I would like to be able to make some king of pause on all treads to be able to allocate the whole available memory for the process without having some crash because a thread would be working (and so allocating memory) during this operation. Thanks for your help. Regards, Vincent. ___ 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
Re: [osg-users] Osg and threads
Hi, I'm still having issues with that... I use a composite viewer with only one view. I tried to call startThreading/stopThreading() but it does nothing... I also tried getAllThreads(...) to get for each thread its thread ID, and it returns me only one thread with ID to 0... even if I know that there is 2 threads running for the rendering... I know I'm not supposed to disturb the rendering threads, but if I cannot get them there is no risk at all... Did I miss something ? Thanks. Regards, Vincent. Le 13/01/2011 11:49, Vincent Bourdier a écrit : Hi Robert, First of all thanks for your answer, I didn't know about the Viewer::startThreading/stopThreading() and this sounds interesting I know that my request seems to be a very strange way to manage memory by pausing threads ... But I am not (completely) crazy. The datas amount I have to manage is the reason why I need to be sure, before loading a file, that I have enought memory including a fixed amount that I reserve for the rest of the code... so I need to saturate memory for a little while to be sure of the amount I can use, and for that I need to stop other threads to be sure they won't crash because of bad_alloc errors that are not managed. Thanks, I'll have a look at the things you gave to me. Regards, Vincent. Le 13/01/2011 11:32, Robert Osfield a écrit : Hi Vincent, The OSG threads that will run automatically are the DatabasePager when you have paged databases and any viewer threads. There is a viewer method for getting the threads. However, the threads are designed to be arbitrarily paused, you can start and stop the viewer threads via Viewer::startThreading/stopThreading() but this creates and destroys threads so not quite what you are after. However, I'm kinda perplexed how you think you might be managing memory more efficiently by pausing threads and doing stuff and then un pausing. I can't help but feel that you need to take a step back and work out what you mean by managing memory efficiently, there are lots of different ways of doing this, but given no information about what you mean and you actual motivation for this others like myself can't really point you in the right direction, the best I can say is from the sound of it you are currently looking in the wrong place. Robert. On Thu, Jan 13, 2011 at 8:14 AM, Vincent Bourdier vincent.bourd...@gmail.com wrote: Hi all, Currently working on a way to manage the memory efficiently, I would like to know what are the osg threads running ? I mean there are some threads in the databasePager, depending on the rendering threading mode there are threads for the render, the cull, or whatever... Did I miss something important ? What are the osg threads ? I would like to be able to make some king of pause on all treads to be able to allocate the whole available memory for the process without having some crash because a thread would be working (and so allocating memory) during this operation. Thanks for your help. Regards, Vincent. ___ 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
[osg-users] OSG and Threads
Hi all, I'm in the process of redesigning our OSG application (the current version is little better than a proof-of-principle prototype, and wasn't written by me) and I'm trying to sort out how the threads will interact. The application has to render imagery from one or more views of a common scene which is updated via a network connection. The rendered imagery will probably need to be delivered back over the network, either by reading back each frame or by using a separate video capture card. My current plan is to have a thread which interacts with the network and converts the packets into updates to the scene graph, then have a second thread which does the rendering, and possibly a third thread to readback and compress the imagery (though this may be done separately via a video capture card). I am also considering a fourth thread to do the scene management stuff, like applying updates from the network and loading models in the background, but I'm not sure how necessary this is. So my questions are as follows: Is my architecture sensible? - Is there a 'better' way to do it? - How closely should I integrate my application with OSG? From a design point of view I'm tempted to create lots of adapters or facades (ie do it properly), but as I will also be the one doing the implementation I'm not sure I can be bothered. How easy is it use OSG in a multi-threaded environment? - Do I need to provide my own mutual exclusion code when modifying the scene graph or is it already taken care of? I think I will need each of the viewpoints to be rendered to a separate window, what is the best mechanism for doing this? - Each view should use the same scene graph except they will each have a different set of render passes and some different shaders and uniforms, is this achievable, and how? - Will each view need to run in a separate thread, or can they all run in one thread? Are there performance implications either way? Thanks in advance for any help. Rob. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
