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Date: Tue, 2 Oct 2018 08:58:59 +0530
From: Anup Patel <anup@...infault.org>
To: Atish Patra <atish.patra@....com>
Cc: Palmer Dabbelt <palmer@...ive.com>,
Albert Ou <aou@...s.berkeley.edu>,
Christoph Hellwig <hch@...radead.org>,
linux-riscv@...ts.infradead.org,
"linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] RISC-V: Show IPI stats
On Tue, Oct 2, 2018 at 8:45 AM Atish Patra <atish.patra@....com> 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@...infault.org>
> >
> > 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?
Regards,
Anup
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