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RISC-V: Show IPI stats

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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

Signed-off-by: Anup Patel <anup@brainfault.org>
[Atish - Fixed checkpatch errors]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>

Changes since v2:
 - Remove use of IPI_CALL_WAKEUP because it's being removed

Changes since v1:
 - Add stub inline show_ipi_stats() function for !CONFIG_SMP
 - Make ipi_names[] dynamically sized at compile time
 - Minor beautification of ipi_names[] using tabs

Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This commit is contained in:
Anup Patel 2018-10-02 12:15:07 -07:00 committed by Palmer Dabbelt
parent 4b26d22fdf
commit 8b20d2db0a
No known key found for this signature in database
GPG key ID: EF4CA1502CCBAB41
3 changed files with 49 additions and 7 deletions
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9
arch/riscv/include/asm/smp.h
View file

@ -25,8 +25,13 @@
extern unsigned long __cpuid_to_hartid_map[NR_CPUS];
#define cpuid_to_hartid_map(cpu) __cpuid_to_hartid_map[cpu]
struct seq_file;
#ifdef CONFIG_SMP
/* print IPI stats */
void show_ipi_stats(struct seq_file *p, int prec);
/* SMP initialization hook for setup_arch */
void __init setup_smp(void);
@ -47,6 +52,10 @@ void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out);
#else
static inline void show_ipi_stats(struct seq_file *p, int prec)
{
}
static inline int riscv_hartid_to_cpuid(int hartid)
{
return 0;

8
arch/riscv/kernel/irq.c
View file

@ -8,6 +8,8 @@
#include <linux/interrupt.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/seq_file.h>
#include <asm/smp.h>
/*
* Possible interrupt causes:
@ -24,6 +26,12 @@
*/
#define INTERRUPT_CAUSE_FLAG (1UL << (__riscv_xlen - 1))
int arch_show_interrupts(struct seq_file *p, int prec)
{
show_ipi_stats(p, prec);
return 0;
}
asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);

39
arch/riscv/kernel/smp.c
View file

@ -22,22 +22,24 @@
#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>
#include <asm/cacheflush.h>
/* A collection of single bit ipi messages. */
static struct {
unsigned long bits ____cacheline_aligned;
} ipi_data[NR_CPUS] __cacheline_aligned;
enum ipi_message_type {
IPI_RESCHEDULE,
IPI_CALL_FUNC,
IPI_MAX
};
/* 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;
int riscv_hartid_to_cpuid(int hartid)
{
int i = -1;
@ -67,6 +69,7 @@ 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);
@ -81,11 +84,15 @@ 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);
@ -111,6 +118,24 @@ send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation)
sbi_send_ipi(cpumask_bits(&hartid_mask));
}
static const char * const ipi_names[] = {
[IPI_RESCHEDULE] = "Rescheduling interrupts",
[IPI_CALL_FUNC] = "Function call 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);