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

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Message-ID: <0e1a0f70-5089-7524-c53b-2762fc174a20@linux.intel.com>
Date:   Tue, 13 Aug 2019 12:13:26 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.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 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.

Thanks
Jin Yao