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Commit 2fb9d206 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Paul Mackerras
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[PATCH] spufs: set irq affinity for running threads 



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: default avatarArnd Bergmann <arndb@de.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent aeb01377

arch/powerpc/platforms/cell/interrupt.c

+26 −16
Original line number Diff line number Diff line
@@ -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;
@@ -188,8 +189,11 @@ static struct iic_regs __iomem *find_iic(int cpu) 


	if (!np) {

		printk(KERN_WARNING "IIC: CPU %d not found\n", cpu);

		iic_regs = NULL;

	} else {

		iic->regs = NULL;

		iic->target_id = 0xff;

		return -ENODEV;

	}



	regs = *(long *)get_property(np, "iic", NULL);



	/* hack until we have decided on the devtree info */
@@ -198,10 +202,10 @@ static struct iic_regs __iomem *find_iic(int cpu) 
		regs += 0x20;



	printk(KERN_DEBUG "IIC for CPU %d at %lx\n", cpu, regs);

		iic_regs = __ioremap(regs, sizeof(struct iic_regs),

	iic->regs = __ioremap(regs, sizeof(struct iic_regs),

					 _PAGE_NO_CACHE);

	}

	return iic_regs;

	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);

	}

arch/powerpc/platforms/cell/interrupt.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/platforms/cell/spu_base.c

+8 −0
Original line number Diff line number Diff line
@@ -507,6 +507,14 @@ int spu_irq_class_1_bottom(struct spu *spu) 
	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)

{

arch/powerpc/platforms/cell/spufs/sched.c

+5 −0
Original line number Diff line number Diff line
@@ -357,6 +357,11 @@ int spu_activate(struct spu_context *ctx, u64 flags) 
	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, raw_smp_processor_id());

	put_active_spu(spu);

	return 0;

}

include/asm-powerpc/spu.h

+1 −0
Original line number Diff line number Diff line
@@ -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,