问题
Some time ago I wrote simple boids simulation using OpenCL (was school assignment), using C#, Cloo for OpenCL and OpenTK for OpenGL output. I tested it on Windows7 with AMD CPU implementation of OpenCL and on friend's NVidia. Now I tried it on Linux (Ubuntu 12.04). I installed amd app sdk and intel sdk. It compiled ok, reference CPU implementation is working fine with graphic output. But when I try to run OpenCL version, it runs for about 1 second (showing what seems like valid output in OpenGL) and then gets killed by SIGXCPU. Tried to google some known issue, but found nothing. So I tried to catch and ignore that signal, but everytime I try, program hangs. When I set mono to catch some different signal (e.g. SIGPIPE), it runs ok (minus that kill when opencl). In Mono, i Tried Mono.UnixSignal as stated in FAQ Tried
Mono.Unix.Native.Stdlib.SetSignalAction ( Mono.Unix.Native.Signum.SIGXCPU, Mono.Unix.Native.SignalAction.Ignore);
then something which doesn't hang, but doesn't help either:
Mono.Unix.Native.Stdlib.SetSignalAction ( Mono.Unix.Native.Signum.SIGXCPU, Mono.Unix.Native.SignalAction.Error);
and even
ignore (0);
Mono.Unix.Native.Stdlib.signal(Mono.Unix.Native.Signum.SIGXCPU, new Mono.Unix.Native.SignalHandler (ignore));
with
static void ignore(int signal) {
}
even when I remove everything else from main, it still hangs sometime after "touching" that signal.
One more weird thing:
Mono.Unix.Native.Stdlib.SetSignalAction ( Mono.Unix.Native.Signum.SIGXCPU, Mono.Unix.Native.SignalAction.Default);
Kills application with SIGXCPU somewhere after Application.EnableVisualStyles(); when I set it right before, not even touching OpenCL this time.
Is there something I missed in Mono? Is it using this signal somewhere internally that it gets in the way of OpenCl?
回答1:
Mono uses SIGXCPU internally for its own purposes, so if you ignore it (or it's raised for some other reason), things will break.
回答2:
SIGXCPU means that you've exceeded a per-process time limit. Once you've exceeded it, you've exceeded it. The process is stuck. You need to use ulimit, or get help from an admin, to set a higher limit.
来源：https://stackoverflow.com/questions/13147375/intel-cpu-opencl-in-mono-killed-by-sigxcpu-ubuntu