Commit 76c43eb5 authored by Gregory CLEMENT's avatar Gregory CLEMENT Committed by Thomas Bogendoerfer
Browse files

MIPS: SMP: Implement parallel CPU bring up for EyeQ 



Added support for starting CPUs in parallel on EyeQ to speed up boot time.

On EyeQ5, booting 8 CPUs is now ~90ms faster.
On EyeQ6, booting 32 CPUs is now ~650ms faster.

Signed-off-by: default avatarGregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
parent 0f4ae7c6

arch/mips/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -617,6 +617,7 @@ config EYEQ 
	select USB_UHCI_BIG_ENDIAN_DESC if CPU_BIG_ENDIAN

	select USB_UHCI_BIG_ENDIAN_MMIO if CPU_BIG_ENDIAN

	select USE_OF

	select HOTPLUG_PARALLEL if SMP

	help

	  Select this to build a kernel supporting EyeQ SoC from Mobileye.
@@ -2287,6 +2288,7 @@ config MIPS_CPS 
	select MIPS_CM

	select MIPS_CPS_PM if HOTPLUG_CPU

	select SMP

	select HOTPLUG_SMT if HOTPLUG_PARALLEL

	select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU

	select SYNC_R4K if (CEVT_R4K || CSRC_R4K)

	select SYS_SUPPORTS_HOTPLUG_CPU

arch/mips/include/asm/topology.h

+3 −0
Original line number Diff line number Diff line
@@ -16,6 +16,9 @@ 
#define topology_core_id(cpu)			(cpu_core(&cpu_data[cpu]))

#define topology_core_cpumask(cpu)		(&cpu_core_map[cpu])

#define topology_sibling_cpumask(cpu)		(&cpu_sibling_map[cpu])



extern struct cpumask __cpu_primary_thread_mask;

#define cpu_primary_thread_mask ((const struct cpumask *)&__cpu_primary_thread_mask)

#endif



#endif /* __ASM_TOPOLOGY_H */

arch/mips/kernel/smp-cps.c

+2 −0
Original line number Diff line number Diff line
@@ -236,6 +236,7 @@ static void __init cps_smp_setup(void) 
			/* Use the number of VPEs in cluster 0 core 0 for smp_num_siblings */

			if (!cl && !c)

				smp_num_siblings = core_vpes;

			cpumask_set_cpu(nvpes, &__cpu_primary_thread_mask);



			for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {

				cpu_set_cluster(&cpu_data[nvpes + v], cl);
@@ -364,6 +365,7 @@ static void __init cps_prepare_cpus(unsigned int max_cpus) 
	cl = cpu_cluster(&current_cpu_data);

	c = cpu_core(&current_cpu_data);

	cluster_bootcfg = &mips_cps_cluster_bootcfg[cl];

	cpu_smt_set_num_threads(core_vpes, core_vpes);

	core_bootcfg = &cluster_bootcfg->core_config[c];

	bitmap_set(cluster_bootcfg->core_power, cpu_core(&current_cpu_data), 1);

	atomic_set(&core_bootcfg->vpe_mask, 1 << cpu_vpe_id(&current_cpu_data));

arch/mips/kernel/smp.c

+18 −0
Original line number Diff line number Diff line
@@ -56,8 +56,10 @@ EXPORT_SYMBOL(cpu_sibling_map); 
cpumask_t cpu_core_map[NR_CPUS] __read_mostly;

EXPORT_SYMBOL(cpu_core_map);



#ifndef CONFIG_HOTPLUG_PARALLEL

static DECLARE_COMPLETION(cpu_starting);

static DECLARE_COMPLETION(cpu_running);

#endif



/*

 * A logical cpu mask containing only one VPE per core to
@@ -74,6 +76,8 @@ static cpumask_t cpu_core_setup_map; 


cpumask_t cpu_coherent_mask;



struct cpumask __cpu_primary_thread_mask __read_mostly;



unsigned int smp_max_threads __initdata = UINT_MAX;



static int __init early_nosmt(char *s)
@@ -374,10 +378,15 @@ asmlinkage void start_secondary(void) 
	set_cpu_core_map(cpu);



	cpumask_set_cpu(cpu, &cpu_coherent_mask);

#ifdef CONFIG_HOTPLUG_PARALLEL

	cpuhp_ap_sync_alive();

#endif

	notify_cpu_starting(cpu);



#ifndef CONFIG_HOTPLUG_PARALLEL

	/* Notify boot CPU that we're starting & ready to sync counters */

	complete(&cpu_starting);

#endif



	synchronise_count_slave(cpu);
@@ -386,11 +395,13 @@ asmlinkage void start_secondary(void) 


	calculate_cpu_foreign_map();



#ifndef CONFIG_HOTPLUG_PARALLEL

	/*

	 * Notify boot CPU that we're up & online and it can safely return

	 * from __cpu_up

	 */

	complete(&cpu_running);

#endif



	/*

	 * irq will be enabled in ->smp_finish(), enabling it too early
@@ -447,6 +458,12 @@ void __init smp_prepare_boot_cpu(void) 
	set_cpu_online(0, true);

}



#ifdef CONFIG_HOTPLUG_PARALLEL

int arch_cpuhp_kick_ap_alive(unsigned int cpu, struct task_struct *tidle)

{

	return mp_ops->boot_secondary(cpu, tidle);

}

#else

int __cpu_up(unsigned int cpu, struct task_struct *tidle)

{

	int err;
@@ -466,6 +483,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle) 
	wait_for_completion(&cpu_running);

	return 0;

}

#endif



#ifdef CONFIG_PROFILING

/* Not really SMP stuff ... */