[Mesa-dev] [PATCH] glsl: optimize list handling in opt_dead_code

[Nicolai Hähnle]

On 18.10.2016 15:07, Jan Ziak wrote:
> On Tue Oct 18 09:29:59 UTC 2016, Eero Tamminen wrote:
>> On 18.10.2016 01:07, Jan Ziak wrote:
>>> - The total number of executed instructions goes down from 64.184 to 63.797
>>>   giga-instructions when Mesa is compiled with "gcc -O0 ..."
>>
>> Please don't do performance related decisions based on data from
>> compiling code with optimizations disabled.  Use -O2 or -O3 (or even
>> better, check both).
>
> Options -O2 and -O3 interfere with profiling tools.
 >
> I will try using -Og the next time.

Just stop and use proper profiling tools like perf that can work with 
optimized tools. You may have to compile with -fno-omit-frame-pointer, 
but anything more than that is going to distort your measurement results 
so much that they're worthless.

Nicolai

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