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Date:   Tue, 27 Sep 2022 16:37:44 -0700
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Subject: Re: [PATCH bpf-next] samples/bpf: offwaketime: pretty print
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To:     Rong Tao <rtoax@foxmail.com>
Cc:     Rong Tao <rongtao@cestc.cn>, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org
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From:   Martin KaFai Lau <martin.lau@linux.dev>
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On 9/25/22 7:22 PM, Rong Tao wrote:
> From: Rong Tao <rongtao@cestc.cn>
> 
> A sample of call stack:
> swapper/10 [
> 	secondary_startup_64_no_verify
> 	cpu_startup_entry
> 	do_idle
> 	schedule_idle
> 	__schedule
> 	__traceiter_sched_switch
> 	__traceiter_sched_switch
> 	-
> 	try_to_wake_up
> 	call_timer_fn
> 	__run_timers.part.0
> 	run_timer_softirq
> 	__softirqentry_text_start
> 	__irq_exit_rcu
> 	sysvec_apic_timer_interrupt
> 	asm_sysvec_apic_timer_interrupt
> 	cpuidle_enter_state
> 	cpuidle_enter
> 	cpuidle_idle_call
> 	do_idle
> 	cpu_startup_entry
> 	secondary_startup_64_no_verify
> ] swapper/10 1
> 
> Signed-off-by: Rong Tao <rongtao@cestc.cn>
> ---
>   samples/bpf/offwaketime_user.c | 14 +++++++-------
>   1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/samples/bpf/offwaketime_user.c b/samples/bpf/offwaketime_user.c
> index b6eedcb98fb9..d89278d62e4e 100644
> --- a/samples/bpf/offwaketime_user.c
> +++ b/samples/bpf/offwaketime_user.c
> @@ -30,9 +30,9 @@ static void print_ksym(__u64 addr)
>   	}
>   
>   	if (PRINT_RAW_ADDR)
> -		printf("%s/%llx;", sym->name, addr);
> +		printf("\t%s/%llx\n", sym->name, addr);

The origin commit intention is to have an external script for post processing. 
Beside, there are bcc, bpftrace, and libbpf-tools which are better places to 
have different output options.  The current code is good enough for sample 
purpose and no need for unnecessary code churn.