Re: [PATCH v3] RISC-V: Show IPI stats
From: Atish Patra
Date: Tue Oct 02 2018 - 15:18:04 EST
On 10/1/18 8:29 PM, Anup Patel wrote:
On Tue, Oct 2, 2018 at 8:45 AM Atish Patra <atish.patra@xxxxxxx> wrote:
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;
This was already there in existing code.
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;
Even this was already there in existing code.
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.
Yes, this one was added by this patch.
Do you want me to send revised patch?
Nope. That's just a one line fix. I fixed it and submitted the patch as
part of my v6.
I will send a separate patch fix for the patch errors introduced by the
existing code as the fix was bit involved.
Regards,
Atish
Regards,
Anup
Regards,
Atish