This patch provides arch_show_interrupts() implementation to show IPI stats via /proc/interrupts.
Now the contents of /proc/interrupts" will look like below: CPU0 CPU1 CPU2 CPU3 8: 17 7 6 14 SiFive PLIC 8 virtio0 10: 10 10 9 11 SiFive PLIC 10 ttyS0 IPI0: 170 673 251 79 Rescheduling interrupts IPI1: 1 12 27 1 Function call interrupts IPI2: 0 0 0 0 CPU wake-up interrupts Signed-off-by: Anup Patel <a...@brainfault.org> --- arch/riscv/include/asm/smp.h | 5 +++++ arch/riscv/kernel/irq.c | 9 +++++++++ arch/riscv/kernel/smp.c | 30 ++++++++++++++++++++++++++++-- 3 files changed, 42 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h index 8145b8657d20..a87e292becba 100644 --- a/arch/riscv/include/asm/smp.h +++ b/arch/riscv/include/asm/smp.h @@ -48,6 +48,11 @@ enum ipi_message_type { void send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation); +struct seq_file; + +/* print IPI stats */ +void show_ipi_stats(struct seq_file *p, int prec); + /* SMP initialization hook for setup_arch */ void __init setup_smp(void); diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c index 7e14b0d9a71d..9177552cd76c 100644 --- a/arch/riscv/kernel/irq.c +++ b/arch/riscv/kernel/irq.c @@ -8,6 +8,7 @@ #include <linux/interrupt.h> #include <linux/irqchip.h> #include <linux/irqdomain.h> +#include <linux/seq_file.h> /* * Possible interrupt causes: @@ -24,6 +25,14 @@ */ #define INTERRUPT_CAUSE_FLAG (1UL << (__riscv_xlen - 1)) +int arch_show_interrupts(struct seq_file *p, int prec) +{ +#ifdef CONFIG_SMP + show_ipi_stats(p, prec); +#endif + return 0; +} + asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long cause) { struct pt_regs *old_regs = set_irq_regs(regs); diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index 629456bb6122..4e67a690edbc 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -22,6 +22,7 @@ #include <linux/interrupt.h> #include <linux/smp.h> #include <linux/sched.h> +#include <linux/seq_file.h> #include <asm/sbi.h> #include <asm/tlbflush.h> @@ -29,6 +30,7 @@ /* A collection of single bit ipi messages. */ static struct { + unsigned long stats[IPI_MAX] ____cacheline_aligned; unsigned long bits ____cacheline_aligned; } ipi_data[NR_CPUS] __cacheline_aligned; @@ -61,6 +63,7 @@ int setup_profiling_timer(unsigned int multiplier) void riscv_software_interrupt(void) { unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits; + unsigned long *stats = ipi_data[smp_processor_id()].stats; /* Clear pending IPI */ csr_clear(sip, SIE_SSIE); @@ -75,11 +78,15 @@ void riscv_software_interrupt(void) if (ops == 0) return; - if (ops & (1 << IPI_RESCHEDULE)) + if (ops & (1 << IPI_RESCHEDULE)) { + stats[IPI_RESCHEDULE]++; scheduler_ipi(); + } - if (ops & (1 << IPI_CALL_FUNC)) + if (ops & (1 << IPI_CALL_FUNC)) { + stats[IPI_CALL_FUNC]++; generic_smp_call_function_interrupt(); + } BUG_ON((ops >> IPI_MAX) != 0); @@ -105,6 +112,25 @@ send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation) sbi_send_ipi(cpumask_bits(&hartid_mask)); } +static const char *ipi_names[IPI_MAX] = { + [IPI_RESCHEDULE] = "Rescheduling interrupts", + [IPI_CALL_FUNC] = "Function call interrupts", + [IPI_CALL_WAKEUP] = "CPU wake-up interrupts", +}; + +void show_ipi_stats(struct seq_file *p, int prec) +{ + unsigned int cpu, i; + + for (i = 0; i < IPI_MAX; i++) { + seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, + prec >= 4 ? " " : ""); + for_each_online_cpu(cpu) + seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]); + seq_printf(p, " %s\n", ipi_names[i]); + } +} + void arch_send_call_function_ipi_mask(struct cpumask *mask) { send_ipi_message(mask, IPI_CALL_FUNC); -- 2.17.1