linux-kernel - Re: [PATCH v3] perf diff: Report noisy for cycles diff

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Date:   Tue, 13 Aug 2019 14:14:18 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     "Jin, Yao" <yao.jin@...ux.intel.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v3] perf diff: Report noisy for cycles diff

On Tue, Aug 13, 2019 at 12:13:26PM +0800, Jin, Yao wrote:
> 
> 
> On 8/12/2019 4:35 PM, Jiri Olsa wrote:
> > On Sat, Aug 10, 2019 at 07:30:29AM +0800, Jin Yao wrote:
> > 
> > SNIP
> > 
> > > +		if (vals[i] != 0)
> > > +			return 0;
> > > +	return 1;
> > > +}
> > > +
> > > +static int print_cycles_spark(char *bf, int size, unsigned long *svals, u64 n)
> > > +{
> > > +	int len = n, printed;
> > > +
> > > +	if (len <= 1)
> > > +		return 0;
> > > +
> > > +	if (len > NUM_SPARKS)
> > > +		len = NUM_SPARKS;
> > > +	if (all_zero(svals, len))
> > > +		return 0;
> > > +
> > > +	printed = print_spark(bf, size, svals, len);
> > > +	printed += scnprintf(bf + printed, size - printed, " ");
> > > +
> > > +	if (n > NUM_SPARKS)
> > > +		printed += scnprintf(bf + printed, size - printed, "..");
> > 
> > will this '..' ever be printed? I can't see that even if I enlarge
> > the column width..
> > 
> > jirka
> > 
> 
> @@ -83,6 +85,8 @@ struct hist_entry_diff {
>                 /* PERF_HPP_DIFF__CYCLES */
>                 s64     cycles;
>         };
> +       struct stats    stats;
> +       unsigned long   svals[NUM_SPARKS];
>  };
> 
> Now we only save 8 items in svals[] (NUM_PARKS = 8). So '..' will not be
> printed. The code of printing '..' is for future possible case.
> 
> If you think it's not necessary, I would remove this.

please remove it then

thanks,
jirka