Hi Hong. On Tue, May 12, 2009 at 03:29:49PM -0400, Hong H. Pham wrote: > irq_choose_cpu() should compare the affinity mask against cpu_online_map > rather than CPU_MASK_ALL, since irq_select_affinity() sets the interrupt's > affinity mask to cpu_online_map "and" CPU_MASK_ALL (which ends up being > just cpu_online_map). The mask comparison in irq_choose_cpu() will always > fail since the two masks are not the same. So the CPU chosen is the first CPU > in the intersection of cpu_online_map and CPU_MASK_ALL, which is always CPU0. > That means all interrupts are reassigned to CPU0... > > Distributing interrupts to CPUs in a linearly increasing round robin fashion > is not optimal for the UltraSPARC T1/T2. Also, the irq_rover in > irq_choose_cpu() causes an interrupt to be assigned to a different > processor each time the interrupt is allocated and released. This may lead > to an unbalanced distribution over time. > > A static mapping of interrupts to processors is done to optimize and balance > interrupt distribution. For the T1/T2, interrupts are spread to different > cores first, and then to strands within a core. > Please include the nice benchmark numbers in the changelog. It is good to know the effect of a patch and how to measure it. > Signed-off-by: Hong H. Pham <hong.pham@xxxxxxxxxxxxx> > --- > arch/sparc/kernel/Makefile | 1 + > arch/sparc/kernel/cpumap.c | 113 ++++++++++++++++++++++++++++++++++++++++++++ > arch/sparc/kernel/cpumap.h | 15 ++++++ > arch/sparc/kernel/irq_64.c | 29 ++---------- > arch/sparc/kernel/smp_64.c | 2 + > 5 files changed, 135 insertions(+), 25 deletions(-) > create mode 100644 arch/sparc/kernel/cpumap.c > create mode 100644 arch/sparc/kernel/cpumap.h > > diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile > index 54742e5..4e217a4 100644 > --- a/arch/sparc/kernel/Makefile > +++ b/arch/sparc/kernel/Makefile > @@ -53,8 +53,9 @@ obj-$(CONFIG_SPARC64) += hvapi.o > obj-$(CONFIG_SPARC64) += sstate.o > obj-$(CONFIG_SPARC64) += mdesc.o > obj-$(CONFIG_SPARC64) += pcr.o > obj-$(CONFIG_SPARC64) += nmi.o > +obj-$(CONFIG_SPARC64) += cpumap.o If you use: obj-$(CONFIG_SPARC64_SMP) += cpumap.o then > > # sparc32 do not use GENERIC_HARDIRQS but uses the generic devres implementation > obj-$(CONFIG_SPARC32) += devres.o > devres-y := ../../../kernel/irq/devres.o > diff --git a/arch/sparc/kernel/cpumap.c b/arch/sparc/kernel/cpumap.c > new file mode 100644 > index 0000000..d539f2f > --- /dev/null > +++ b/arch/sparc/kernel/cpumap.c > @@ -0,0 +1,113 @@ > +/* cpumap.c: used for optimizing CPU assignment > + * > + * Copyright (C) 2009 Hong H. Pham <hong.pham@xxxxxxxxxxxxx> > + */ > + > +#include <linux/module.h> > +#include <linux/kernel.h> > +#include <linux/init.h> > +#include <linux/cpumask.h> > +#include <linux/spinlock.h> > +#include "cpumap.h" > + > + > +#ifdef CONFIG_SMP you can drop this ifdef. Sam -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
