Re: 1Khz timer interrupt | |
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Hello Juergen, >> Obviously one possible way to achieve is to set HZ to 1000. I'm affraid >> however that this way will add too much overhead >> to the system. >> >> I wonder if the i.mx27 BSP support some different way to achieve it? > > High Resolution Timer? Yeah.. That will make the problem even worse... It will load the CPU even more because the HRT handling and administration/scheduling is heavier. On ARM (AT91), with HRT I measured a 2us interrupt top-half length, which results in a 150us during scheduler activities after that. With the old-fashioned ticking implementation it is about 2us/50us load. So, on AT91 a 1KHz timer interrupt resulted in about 10-15% average load, while the old implementation is far less. And because the HRT can even generate sub-millisecond intervals it is easily possible to choke the system that much that it does not do much more than only handling timer interrupts... (I used a patch that enables me to set a min_delta_ns to some decent value so that this does not happen...) On Atmel AT91 there are Timer Counter blocks that could generate periodic interrupts, I do not know if similar peripherals are available on i.MX27. If so, you can probably use those. Kind Regards, Remy ------------------------------------------------------------------- List admin: http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel FAQ: http://www.arm.linux.org.uk/mailinglists/faq.php Etiquette: http://www.arm.linux.org.uk/mailinglists/etiquette.php
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