Re: [PATCH v2 4/7] perf diff: Use hists to manage basic blocks per symbol

From: "Jin, Yao" <yao.jin@linux.intel.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: acme@kernel.org, jolsa@kernel.org, peterz@infradead.org,
	mingo@redhat.com, alexander.shishkin@linux.intel.com,
	Linux-kernel@vger.kernel.org, ak@linux.intel.com,
	kan.liang@intel.com, yao.jin@intel.com
Subject: Re: [PATCH v2 4/7] perf diff: Use hists to manage basic blocks per symbol
Date: Thu, 6 Jun 2019 09:26:18 +0800	[thread overview]
Message-ID: <1a9d402b-5f60-d34a-74fe-3bfb78c9b31e@linux.intel.com> (raw)
In-Reply-To: <20190605114432.GD5868@krava>

On 6/5/2019 7:44 PM, Jiri Olsa wrote:
> On Mon, Jun 03, 2019 at 10:36:14PM +0800, Jin Yao wrote:
> 
> SNIP
> 
>>   					   sort_compute);
>>   }
>>   
>> +static int64_t
>> +hist_entry__cmp_cycles_idx(struct perf_hpp_fmt *fmt __maybe_unused,
>> +			   struct hist_entry *left __maybe_unused,
>> +			   struct hist_entry *right __maybe_unused)
>> +{
>> +	return 0;
>> +}
>> +
>>   static void hists__process(struct hists *hists)
>>   {
>>   	if (show_baseline_only)
>> @@ -746,6 +930,8 @@ static void data_process(void)
>>   	struct perf_evsel *evsel_base;
>>   	bool first = true;
>>   
>> +	memset(&dummy_al, 0, sizeof(dummy_al));
> 
> why is this needed? it's zero by static declaration, and it's never set, right?
> 
> jirka
> 

C standard says yes for initializing static variables to 0, but I just 
want to avoid any potential for unexpected behavior. Maybe I was over 
thinking it. I will remove this line.

Thanks
Jin Yao