linux-kernel - Re: [PATCH V5 5/6] Sched: Add tracepoint for sched time slice extension

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Message-ID: <20250604103644.4b41b9a3@gandalf.local.home>
Date: Wed, 4 Jun 2025 10:36:44 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Prakash Sangappa <prakash.sangappa@...cle.com>
Cc: linux-kernel@...r.kernel.org, peterz@...radead.org,
 mathieu.desnoyers@...icios.com, tglx@...utronix.de, bigeasy@...utronix.de,
 kprateek.nayak@....com, vineethr@...ux.ibm.com
Subject: Re: [PATCH V5 5/6] Sched: Add tracepoint for sched time slice
 extension

On Tue,  3 Jun 2025 23:36:53 +0000
Prakash Sangappa <prakash.sangappa@...cle.com> wrote:

> @@ -134,6 +138,10 @@ __always_inline unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
>  		ti_work = read_thread_flags();
>  	}
>  
> +	if (ti_work_cleared)
> +		trace_sched_delay_resched(current, ti_work_cleared &
> +			(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY));
> +

Please make the above into a conditional tracepoint and you can also just
pass in ti_work_cleared. No reason to do that outside the tracepoint. As
the above is always checked regardless if tracing is enabled or not.

TRACE_EVENT_CONDITION(sched_delay_resched,

	TP_PROTO(struct task_struct *p, unsigned int ti_work_cleared),

	TP_ARGS(p, ti_work_cleared),

	TP_CONDITION(ti_work_cleared),

	TP_STRUCT__entry(
		__array( char, comm, TASK_COMM_LEN	)
		__field( pid_t, pid			)
		__field( int, cpu			)
		__field( int, flg			)
	),

	TP_fast_assign(
		memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
		__entry->pid		= p->pid;
		__entry->cpu 		= task_cpu(p);
		__entry->flg		= ti_work_cleared & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY);
	),


-- Steve