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Message-ID: <54503b86-cb77-9eaf-6bd9-5e8caa2ebb78@wdc.com>
Date: Tue, 2 Oct 2018 12:18:01 -0700
From: Atish Patra <atish.patra@....com>
To: Anup Patel <anup@...infault.org>
Cc: Palmer Dabbelt <palmer@...ive.com>,
Albert Ou <aou@...s.berkeley.edu>,
Christoph Hellwig <hch@...radead.org>,
"linux-riscv@...ts.infradead.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 10/1/18 8:29 PM, Anup Patel wrote:
> 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?
>
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
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