From: Martin Pieuchot <mpi@openbsd.org>
Subject: Re: dt: Trace tracing program
To: Christian Ludwig <christian_ludwig@genua.de>
Cc: tech@openbsd.org
Date: Mon, 5 Feb 2024 16:14:32 +0100

On 02/02/24(Fri) 16:24, Christian Ludwig wrote:
> For the sake of visibility, also trace the tracing program itself.
> If you really wanted to hide it, add a filter to your probes, like:

I'm not sure about that.  Why do you want to see the tracing program?
What are you trying to monitor?

> 
> | BEGIN {
> |   @tracer = pid;
> | }
> |
> | profile:hz:100 / pid != @tracer /
> | {
> |   @[kstack] = count();
> | }
> ---
>  sys/dev/dt/dt_dev.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/sys/dev/dt/dt_dev.c b/sys/dev/dt/dt_dev.c
> index 12c5390cdbb..71e90a71d2b 100644
> --- a/sys/dev/dt/dt_dev.c
> +++ b/sys/dev/dt/dt_dev.c
> @@ -702,10 +702,6 @@ dt_pcb_filter(struct dt_pcb *dp)
>  	unsigned int var = 0;
>  	int match = 1;
>  
> -	/* Filter out tracing program. */
> -	if (dp->dp_sc->ds_pid == p->p_p->ps_pid)
> -		return 1;
> -
>  	switch (dtf->dtf_variable) {
>  	case DT_FV_PID:
>  		var = p->p_p->ps_pid;
> -- 
> 2.34.1
>