For far, all SPU triggered interrupts always end up on
the first SMT thread, which is a bad solution.
This patch implements setting the affinity to the
CPU that was running last when entering execution on
an SPU. This should result in a significant reduction
in IPI calls and better cache locality for SPE thread
specific data.
Signed-off-by: Arnd Bergmann <[email protected]>
Index: linux-2.6.15-rc/include/asm-powerpc/spu.h
===================================================================
--- linux-2.6.15-rc.orig/include/asm-powerpc/spu.h
+++ linux-2.6.15-rc/include/asm-powerpc/spu.h
@@ -147,6 +147,7 @@ struct spu *spu_alloc(void);
void spu_free(struct spu *spu);
int spu_irq_class_0_bottom(struct spu *spu);
int spu_irq_class_1_bottom(struct spu *spu);
+void spu_irq_setaffinity(struct spu *spu, int cpu);
extern struct spufs_calls {
asmlinkage long (*create_thread)(const char __user *name,
Index: linux-2.6.15-rc/arch/powerpc/platforms/cell/interrupt.c
===================================================================
--- linux-2.6.15-rc.orig/arch/powerpc/platforms/cell/interrupt.c
+++ linux-2.6.15-rc/arch/powerpc/platforms/cell/interrupt.c
@@ -23,6 +23,7 @@
#include <linux/config.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
+#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/types.h>
@@ -55,6 +56,7 @@ struct iic_regs {
struct iic {
struct iic_regs __iomem *regs;
+ u8 target_id;
};
static DEFINE_PER_CPU(struct iic, iic);
@@ -172,12 +174,11 @@ int iic_get_irq(struct pt_regs *regs)
return irq;
}
-static struct iic_regs __iomem *find_iic(int cpu)
+static int setup_iic(int cpu, struct iic *iic)
{
struct device_node *np;
int nodeid = cpu / 2;
unsigned long regs;
- struct iic_regs __iomem *iic_regs;
for (np = of_find_node_by_type(NULL, "cpu");
np;
@@ -188,20 +189,23 @@ static struct iic_regs __iomem *find_iic
if (!np) {
printk(KERN_WARNING "IIC: CPU %d not found\n", cpu);
- iic_regs = NULL;
- } else {
- regs = *(long *)get_property(np, "iic", NULL);
-
- /* hack until we have decided on the devtree info */
- regs += 0x400;
- if (cpu & 1)
- regs += 0x20;
-
- printk(KERN_DEBUG "IIC for CPU %d at %lx\n", cpu, regs);
- iic_regs = __ioremap(regs, sizeof(struct iic_regs),
- _PAGE_NO_CACHE);
+ iic->regs = NULL;
+ iic->target_id = 0xff;
+ return -ENODEV;
}
- return iic_regs;
+
+ regs = *(long *)get_property(np, "iic", NULL);
+
+ /* hack until we have decided on the devtree info */
+ regs += 0x400;
+ if (cpu & 1)
+ regs += 0x20;
+
+ printk(KERN_DEBUG "IIC for CPU %d at %lx\n", cpu, regs);
+ iic->regs = __ioremap(regs, sizeof(struct iic_regs),
+ _PAGE_NO_CACHE);
+ iic->target_id = (nodeid << 4) + ((cpu & 1) ? 0xf : 0xe);
+ return 0;
}
#ifdef CONFIG_SMP
@@ -227,6 +231,12 @@ void iic_cause_IPI(int cpu, int mesg)
out_be64(&per_cpu(iic, cpu).regs->generate, (IIC_NUM_IPIS - 1 - mesg) << 4);
}
+u8 iic_get_target_id(int cpu)
+{
+ return per_cpu(iic, cpu).target_id;
+}
+EXPORT_SYMBOL_GPL(iic_get_target_id);
+
static irqreturn_t iic_ipi_action(int irq, void *dev_id, struct pt_regs *regs)
{
smp_message_recv(iic_irq_to_ipi(irq), regs);
@@ -276,7 +286,7 @@ void iic_init_IRQ(void)
irq_offset = 0;
for_each_cpu(cpu) {
iic = &per_cpu(iic, cpu);
- iic->regs = find_iic(cpu);
+ setup_iic(cpu, iic);
if (iic->regs)
out_be64(&iic->regs->prio, 0xff);
}
Index: linux-2.6.15-rc/arch/powerpc/platforms/cell/interrupt.h
===================================================================
--- linux-2.6.15-rc.orig/arch/powerpc/platforms/cell/interrupt.h
+++ linux-2.6.15-rc/arch/powerpc/platforms/cell/interrupt.h
@@ -54,6 +54,7 @@ extern void iic_setup_cpu(void);
extern void iic_local_enable(void);
extern void iic_local_disable(void);
+extern u8 iic_get_target_id(int cpu);
extern void spider_init_IRQ(void);
extern int spider_get_irq(unsigned long int_pending);
Index: linux-2.6.15-rc/arch/powerpc/platforms/cell/spu_base.c
===================================================================
--- linux-2.6.15-rc.orig/arch/powerpc/platforms/cell/spu_base.c
+++ linux-2.6.15-rc/arch/powerpc/platforms/cell/spu_base.c
@@ -507,6 +507,14 @@ int spu_irq_class_1_bottom(struct spu *s
return ret;
}
+void spu_irq_setaffinity(struct spu *spu, int cpu)
+{
+ u64 target = iic_get_target_id(cpu);
+ u64 route = target << 48 | target << 32 | target << 16;
+ spu_int_route_set(spu, route);
+}
+EXPORT_SYMBOL_GPL(spu_irq_setaffinity);
+
static void __iomem * __init map_spe_prop(struct device_node *n,
const char *name)
{
Index: linux-2.6.15-rc/arch/powerpc/platforms/cell/spufs/sched.c
===================================================================
--- linux-2.6.15-rc.orig/arch/powerpc/platforms/cell/spufs/sched.c
+++ linux-2.6.15-rc/arch/powerpc/platforms/cell/spufs/sched.c
@@ -357,6 +357,11 @@ int spu_activate(struct spu_context *ctx
if (!spu)
return (signal_pending(current)) ? -ERESTARTSYS : -EAGAIN;
bind_context(spu, ctx);
+ /*
+ * We're likely to wait for interrupts on the same
+ * CPU that we are now on, so send them here.
+ */
+ spu_irq_setaffinity(spu, smp_processor_id());
put_active_spu(spu);
return 0;
}
--
-
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