Jim Donelson wrote: > >>Would disabling / enabling the interrupt be possible in user mode > >>(especially when running MMU enabled "full" Linux ? > > That would depend on the arch of the MCU - May or may not be > enforceable by the kernel. > What should be done is that a "mutex" object should do this for you > (i.e patch the code in the kernel).
The whole point of futex is to _avoid_ system calls when possible, for performance. System calls aren't super slow, but locking primitives are called very often in some code. So good performance means finding a way to simulate atomic memory updates in userspace without a user/kernel transition. If you can't find any other way, then do that, but it's best avoided. > I am amazed that the base design did not have atomic instructions. Well, they aren't free in terms of FPGA resources, they'd make the attainable clock speed a bit slower, and they aren't necessary if you have one CPU. But I agree they would have made sense an an optional feature. I wonder if load-locked/store-conditional is covered by patents... -- Jamie _______________________________________________ uClinux-dev mailing list uClinux-dev@uclinux.org http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by uclinux-dev@uclinux.org To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev
