Re: [PATCH v3 1/6] perf header: Record first sample time and last sample time in perf file header

[Jiri Olsa]

On Thu, Sep 28, 2017 at 08:45:16PM +0800, Jin Yao wrote:

SNIP

> +		return ret;
> +
> +	return do_write(ff, &evlist->last_sample_time,
> +			sizeof(evlist->last_sample_time));
> +}
> +
>  static void print_hostname(struct feat_fd *ff, FILE *fp)
>  {
>  	fprintf(fp, "# hostname : %s\n", ff->ph->env.hostname);
> @@ -1506,6 +1520,19 @@ static void print_group_desc(struct feat_fd *ff, FILE *fp)
>  	}
>  }
>  
> +static void print_sample_time(struct feat_fd *ff, FILE *fp)
> +{
> +	struct perf_session *session;
> +
> +	session = container_of(ff->ph, struct perf_session, header);
> +
> +	fprintf(fp, "# time of first sample : %" PRIu64 "\n",
> +		session->evlist->first_sample_time);
> +
> +	fprintf(fp, "# time of last sample : %" PRIu64 "\n",
> +		session->evlist->last_sample_time);

this could be done in some follow up patch, but could we
display this in some human readable way.. 

# time of first sample : 218077073264620
# time of last sample : 218077073395488

jirka