Re: [PATCH V11 15/17] RISC-V: paravirt: pvqspinlock: Add trace point for pv_kick/wait

[Leonardo Bras <leobras@redhat.com>]

On Sun, Sep 10, 2023 at 04:29:09AM -0400, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
> 
> Add trace point for pv_kick/wait, here is the output:
> 
>  entries-in-buffer/entries-written: 33927/33927   #P:12
> 
>                                 _-----=> irqs-off/BH-disabled
>                                / _----=> need-resched
>                               | / _---=> hardirq/softirq
>                               || / _--=> preempt-depth
>                               ||| / _-=> migrate-disable
>                               |||| /     delay
>            TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
>               | |         |   |||||     |         |
>              sh-100     [001] d..2.    28.312294: pv_wait: cpu 1 out of wfi
>          <idle>-0       [000] d.h4.    28.322030: pv_kick: cpu 0 kick target cpu 1
>              sh-100     [001] d..2.    30.982631: pv_wait: cpu 1 out of wfi
>          <idle>-0       [000] d.h4.    30.993289: pv_kick: cpu 0 kick target cpu 1
>              sh-100     [002] d..2.    44.987573: pv_wait: cpu 2 out of wfi
>          <idle>-0       [000] d.h4.    44.989000: pv_kick: cpu 0 kick target cpu 2
>          <idle>-0       [003] d.s3.    51.593978: pv_kick: cpu 3 kick target cpu 4
>       rcu_sched-15      [004] d..2.    51.595192: pv_wait: cpu 4 out of wfi
> lock_torture_wr-115     [004] ...2.    52.656482: pv_kick: cpu 4 kick target cpu 2
> lock_torture_wr-113     [002] d..2.    52.659146: pv_wait: cpu 2 out of wfi
> lock_torture_wr-114     [008] d..2.    52.659507: pv_wait: cpu 8 out of wfi
> lock_torture_wr-114     [008] d..2.    52.663503: pv_wait: cpu 8 out of wfi
> lock_torture_wr-113     [002] ...2.    52.666128: pv_kick: cpu 2 kick target cpu 8
> lock_torture_wr-114     [008] d..2.    52.667261: pv_wait: cpu 8 out of wfi
> lock_torture_wr-114     [009] .n.2.    53.141515: pv_kick: cpu 9 kick target cpu 11
> lock_torture_wr-113     [002] d..2.    53.143339: pv_wait: cpu 2 out of wfi
> lock_torture_wr-116     [007] d..2.    53.143412: pv_wait: cpu 7 out of wfi
> lock_torture_wr-118     [000] d..2.    53.143457: pv_wait: cpu 0 out of wfi
> lock_torture_wr-115     [008] d..2.    53.143481: pv_wait: cpu 8 out of wfi
> lock_torture_wr-117     [011] d..2.    53.143522: pv_wait: cpu 11 out of wfi
> lock_torture_wr-117     [011] ...2.    53.143987: pv_kick: cpu 11 kick target cpu 8
> lock_torture_wr-115     [008] ...2.    53.144269: pv_kick: cpu 8 kick target cpu 7
> 
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>
> ---
>  arch/riscv/kernel/qspinlock_paravirt.c        |  8 +++
>  .../kernel/trace_events_filter_paravirt.h     | 60 +++++++++++++++++++
>  2 files changed, 68 insertions(+)
>  create mode 100644 arch/riscv/kernel/trace_events_filter_paravirt.h
> 
> diff --git a/arch/riscv/kernel/qspinlock_paravirt.c b/arch/riscv/kernel/qspinlock_paravirt.c
> index 571626f350be..5d298e989b99 100644
> --- a/arch/riscv/kernel/qspinlock_paravirt.c
> +++ b/arch/riscv/kernel/qspinlock_paravirt.c
> @@ -9,10 +9,16 @@
>  #include <asm/qspinlock_paravirt.h>
>  #include <asm/sbi.h>
>  
> +#define CREATE_TRACE_POINTS
> +#include "trace_events_filter_paravirt.h"
> +
>  void pv_kick(int cpu)
>  {
>  	sbi_ecall(SBI_EXT_PVLOCK, SBI_EXT_PVLOCK_KICK_CPU,
>  		  cpuid_to_hartid_map(cpu), 0, 0, 0, 0, 0);
> +
> +	trace_pv_kick(smp_processor_id(), cpu);
> +
>  	return;
>  }
>  
> @@ -28,6 +34,8 @@ void pv_wait(u8 *ptr, u8 val)
>  		goto out;
>  
>  	wait_for_interrupt();
> +
> +	trace_pv_wait(smp_processor_id());
>  out:
>  	local_irq_restore(flags);
>  }
> diff --git a/arch/riscv/kernel/trace_events_filter_paravirt.h b/arch/riscv/kernel/trace_events_filter_paravirt.h
> new file mode 100644
> index 000000000000..9ff5aa451b12
> --- /dev/null
> +++ b/arch/riscv/kernel/trace_events_filter_paravirt.h
> @@ -0,0 +1,60 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c), 2023 Alibaba Cloud
> + * Authors:
> + *	Guo Ren <guoren@linux.alibaba.com>
> + */
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM paravirt
> +
> +#if !defined(_TRACE_PARAVIRT_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_PARAVIRT_H
> +
> +#include <linux/tracepoint.h>
> +
> +TRACE_EVENT(pv_kick,
> +	TP_PROTO(int cpu, int target),
> +	TP_ARGS(cpu, target),
> +
> +	TP_STRUCT__entry(
> +		__field(int, cpu)
> +		__field(int, target)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->cpu = cpu;
> +		__entry->target = target;
> +	),
> +
> +	TP_printk("cpu %d kick target cpu %d",
> +		__entry->cpu,
> +		__entry->target
> +	)
> +);
> +
> +TRACE_EVENT(pv_wait,
> +	TP_PROTO(int cpu),
> +	TP_ARGS(cpu),
> +
> +	TP_STRUCT__entry(
> +		__field(int, cpu)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->cpu = cpu;
> +	),
> +
> +	TP_printk("cpu %d out of wfi",
> +		__entry->cpu
> +	)
> +);
> +
> +#endif /* _TRACE_PARAVIRT_H || TRACE_HEADER_MULTI_READ */
> +
> +#undef TRACE_INCLUDE_PATH
> +#undef TRACE_INCLUDE_FILE
> +#define TRACE_INCLUDE_PATH ../../../arch/riscv/kernel/
> +#define TRACE_INCLUDE_FILE trace_events_filter_paravirt
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
> -- 
> 2.36.1
> 

LGTM:
Reviewed-by: Leonardo Bras <leobras@redhat.com>

Thanks!
Leo