Re: [PATCH v3] RISC-V: Show IPI stats
From: Atish Patra
Date: Mon Oct 01 2018 - 23:16:07 EST
On 9/28/18 11:26 PM, Anup Patel wrote:
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@xxxxxxxxxxxxxx>
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
---
arch/riscv/include/asm/smp.h | 9 +++++++++
arch/riscv/kernel/irq.c | 8 ++++++++
arch/riscv/kernel/smp.c | 39 +++++++++++++++++++++++++++++-------
3 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index fce312ce3516..5278ae8f1346 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -25,8 +25,13 @@
extern unsigned long __cpuid_to_hardid_map[NR_CPUS];
#define cpuid_to_hardid_map(cpu) __cpuid_to_hardid_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;
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index ca4593317e45..48e6b7db83a1 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -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);
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 89d95866f562..686fa7a427ff 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -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 *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);
some checkpatch errors.
patches/smp_cleanup/0014-RISC-V-Show-IPI-stats.patch
----------------------------------------------------
WARNING: Missing a blank line after declarations
#115: FILE: arch/riscv/kernel/smp.c:40:
+ unsigned long stats[IPI_MAX] ____cacheline_aligned;
+ unsigned long bits ____cacheline_aligned;
WARNING: usage of NR_CPUS is often wrong - consider using
cpu_possible(), num_possible_cpus(), for_each_possible_cpu(), etc
#116: FILE: arch/riscv/kernel/smp.c:41:
+} ipi_data[NR_CPUS] __cacheline_aligned;
WARNING: static const char * array should probably be static const char
* const
#151: FILE: arch/riscv/kernel/smp.c:121:
+static const char *ipi_names[] = {
total: 0 errors, 3 warnings, 120 lines checked
Let me know if they were ignored on purpose.
Regards,
Atish