Anders Blomdell wrote:
When trying to run Xenomai on PowerPC with OpenPIC, I have (finally) found that interrupt latency is much improved with the following patch:--- arch/ppc/syslib/open_pic.c~ 2006-01-08 03:15:24.000000000 +0100 +++ arch/ppc/syslib/open_pic.c 2006-02-07 16:56:14.000000000 +0100 @@ -820,7 +820,7 @@ */ static void openpic_ack_irq(unsigned int irq_nr) { -#ifdef __SLOW_VERSION__ +#if defined(__SLOW_VERSION__) || defined(CONFIG_IPIPE) openpic_disable_irq(irq_nr); openpic_eoi(); #else @@ -831,7 +831,7 @@ static void openpic_end_irq(unsigned int irq_nr) { -#ifdef __SLOW_VERSION__ +#if defined(__SLOW_VERSION__) || defined(CONFIG_IPIPE) if (!(irq_desc[irq_nr].status & (IRQ_DISABLED|IRQ_INPROGRESS)) && irq_desc[irq_nr].action) openpic_enable_irq(irq_nr);The reason for this, is that the fast version doesn't call openpic_eoi until the interrupt is ended, which means that all RT-interrupts are delayed by a pending Linux interrupt.
Gasp. Will check on my Icecube asap, thanks (a lot). -- Philippe.
