Hello everyone, This is a very interesting road, so I'm calling out to see if anyone might have idea on how to minimize an issue I am having on an embedded imaging system.
This device is performing an insane amount of image processing from two firewire cameras. We're talking on the order of ~120 fps. Each of these is being processed, and various image masks are saved to the local hard drive, for later use, and are provided to the client side of the device via an embedded web server within the analyzer software. What is happening is, once a minute, a new instance of the imagers is launched. These two imagers then connect to the firewire cameras, and go to work. Over time, ~1-2 weeks, the imagers start to fail with at an increasing rate, as the kernel starts to kill them as the firewire stack cannot allocate enough DMA buffers to communicate with the cameras. Note, there is plenty of ram in DMA32, however, it is fragmented to the point that the required contiguous 128k page areas are not available. The system has tens of thousands of 4&8k pages, however. A short term solution I have found is to simply request the kernel drop all of it's caches on the floor. This, in turn, frees up a LOT of memory, and subsequently, allocs can function without an issue, until it occurs again. I believe the issue is that the system is creation beeeelions of little files, and the I/O caching system is using unused ram, of which there is plenty. The caching, however, it breaking up large page areas into the 4 and 8k areas, fragmenting the RAM significantly. Is there possibly a way to limit Linux's caching system to prevent the use of a portion of the DMA32 zone in its entirety? Or perhaps block off portions of the DMA32 zone for use only by firewire and/or DMA transfers? Kind of describing the issue out loud, wasn't sure if anyone had any good ideas to minimize the issue. -- -- Thomas
_______________________________________________ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
