Driver IO Busywait Kernel Driver Question

skibud2 · 10-27-2008, 03:13 PM

I have a driver that does the following:

// Kind of like a serial driver with no interrupt

for (c in buff){
write_to_reg(c);
while(statusreg & BUSY_MASK); // busy wait for operation to complete
}

Naturally, this causes a lot of busy waiting, and the CPU usage goes up. Is there a good way to reduce the CPU usage in this circumstance?

Thanks!

CRC123 · 10-27-2008, 03:19 PM

This is just off the top of my head but I think you could put a 'sleep' call inside your loop and the process would go to sleep for a bit before it tried the while statement again. Granted the smallest sleep increment is a second I think so that is quite long in computer terms, but it may solve your problem

skibud2 · 10-27-2008, 07:19 PM

This is all being done in an ioctl call. Anyone else have any ideas?