Re: [PATCH v3 15/23] trace-cmd: Set order and priorities when applying timestamp corrections

[Steven Rostedt <rostedt@xxxxxxxxxxx>]

On Wed, 24 Mar 2021 15:04:10 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:

> @@ -1296,15 +1287,23 @@ static unsigned long long timestamp_correct(unsigned long long ts,
>  static unsigned long long timestamp_calc(unsigned long long ts,
>  					 struct tracecmd_input *handle)
>  {
> -	ts = timestamp_correct(ts, handle);
> +	/* Guest trace file, sync with host timestamps */
> +	if (handle->host.sync_enable)
> +		ts = timestamp_host_sync(ts, handle);
>  
> -	if (handle->ts2secs)
> +	if (handle->ts2secs) {
> +		/* user specified clock frequency */
>  		ts *= handle->ts2secs;
> -	else if (handle->tsc_calc.mult) {
> +	} else if (handle->tsc_calc.mult) {
> +		/* auto calculated TSC clock frequency */
>  		ts -= handle->tsc_calc.offset;
>  		ts = mul_u64_u32_shr(ts, handle->tsc_calc.mult, handle->tsc_calc.shift);
>  	}
>  
> +	/* User specified time offset with --ts-offset or --date options */
> +	if (handle->ts_offset)
> +		ts += handle->ts_offset;
> +
>  	return ts;
>  }


Now that I'm playing with this, I find I want to see what the result is
without the tsc_calc.offset, but can't do it. I'm thinking that the
--ts-offset should modify that instead:

	bool ts_offset_set = false;
	[..]

	} else if (handel->tsc_calc.mult) {
		ts_offset_set = true;
		if (handle->ts_offset)
			ts += handle->ts_offset;
		else
			ts -= handle->tsc_calc.offset;
		[..]
	}

	if (handle->ts_offset && !ts_offset_set)
		ts += handle->ts_offset;

Or should we add another option to modify the ts_calc.offset?

Thoughts?

-- Steve