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

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Date:   Wed, 12 Jun 2019 14:11:44 +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 v2 4/7] perf diff: Use hists to manage basic blocks per
 symbol



On 6/11/2019 4:56 PM, Jiri Olsa wrote:
> On Sat, Jun 08, 2019 at 07:41:47PM +0800, Jin, Yao wrote:
>>
>>
>> On 6/5/2019 7:44 PM, Jiri Olsa wrote:
>>> On Mon, Jun 03, 2019 at 10:36:14PM +0800, Jin Yao wrote:
>>>
>>> SNIP
>>>
>>>> diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
>>>> index 43623fa..d1641da 100644
>>>> --- a/tools/perf/util/sort.h
>>>> +++ b/tools/perf/util/sort.h
>>>> @@ -79,6 +79,9 @@ struct hist_entry_diff {
>>>>    		/* HISTC_WEIGHTED_DIFF */
>>>>    		s64	wdiff;
>>>> +
>>>> +		/* PERF_HPP_DIFF__CYCLES */
>>>> +		s64	cycles;
>>>>    	};
>>>>    };
>>>> @@ -143,6 +146,9 @@ struct hist_entry {
>>>>    	struct branch_info	*branch_info;
>>>>    	long			time;
>>>>    	struct hists		*hists;
>>>> +	void			*block_hists;
>>>> +	int			block_idx;
>>>> +	int			block_num;
>>>>    	struct mem_info		*mem_info;
>>>>    	struct block_info	*block_info;
>>>
>>> could you please not add the new block* stuff in here,
>>> and instead use the "c2c model" and use yourr own struct
>>> on top of hist_entry? we are trying to librarize this
>>> stuff and keep only necessary things in here..
>>>
>>> you're already using hist_entry_ops, so should be easy
>>>
>>> something like:
>>>
>>> 	struct block_hist_entry {
>>> 		void			*block_hists;
>>> 		int			block_idx;
>>> 		int			block_num;
>>> 		struct block_info	*block_info;
>>>
>>> 		struct hist_entry	he;
>>> 	};
>>>
>>>
>>>
>>> jirka
>>>
>>
>> Hi Jiri,
>>
>> After more considerations, maybe I can't move these stuffs from hist_entry
>> to block_hist_entry.
> 
> why?
> 
>>
>> Actually we use 2 kinds of hist_entry in this patch series. On kind of
>> hist_entry is for symbol/function. The other kind of hist_entry is for basic
>> block.
> 
> correct
> 
> so the way I see it the processing goes like this:
> 
> 
> 1) there's standard hist_entry processing ending up
>     with evsel->hists->rb_root full of hist entries
> 
> 2) then you process every hist_entry and create
>     new 'struct hists' for each and fill it with
>     symbol counts data
> 
> 
> 
> you could add 'struct hist_entry_ops' for the 1) processing
> that adds the 'struct hists' object for each hist_entry
> 
> and add another 'struct hist_entry_ops' for 2) processing
> to carry the block data for each hist_entry
> 
> jirka
> 

Hi Jiri,

Yes, I can use two hist_entry_ops but one thing is still difficult to 
handle that is the printing of blocks.

One function may contain multiple blocks so I add 'block_num' in 'struct 
hist_entry' to record the number of blocks.

In patch "perf diff: Print the basic block cycles diff", I reuse most of 
current code to print the blocks. The major change is:

  static int hist_entry__fprintf(struct hist_entry *he, size_t size,
                                char *bf, size_t bfsz, FILE *fp,
                                bool ignore_callchains) {

+       if (he->block_hists)
+               return hist_entry__block_fprintf(he, bf, size, fp);
+
         hist_entry__snprintf(he, &hpp);
}

+static int hist_entry__block_fprintf(struct hist_entry *he,
+                                    char *bf, size_t size,
+                                    FILE *fp)
+{
+       int ret = 0;
+
+       for (int i = 0; i < he->block_num; i++) {
+               struct perf_hpp hpp = {
+                       .buf            = bf,
+                       .size           = size,
+                       .skip           = false,
+               };
+
+               he->block_idx = i;
+               hist_entry__snprintf(he, &hpp);
+
+               if (!hpp.skip)
+                       ret += fprintf(fp, "%s\n", bf);
+       }
+
+       return ret;
+}
+

So it looks at least I need to add 'block_num' to 'struct hist_entry', 
otherwise I can't reuse most of codes.

Any idea for 'block_num'?

Thanks
Jin Yao