Re: [PATCH 1/2] Prevent excessive major gcs by having decent amount of unused heap

[Sven Hartrumpf]

Hi Mario.

Mario wrote, 2021-01-12 12:39:
> Hi Sven,
>
> On Tue, 12 Jan 2021 11:42:31 +0100 (CET) Sven Hartrumpf <hartrumpf@gmx.net> 
> wrote:
>
>> Mario, 2021-01-10 10:03:
>>>
>>> On Sat, 09 Jan 2021 15:14:31 +0100 (CET) Sven Hartrumpf <hartrumpf@gmx.net> 
>>> wrote:
>>>
>>>> Thanks for the patches and the tests!
>>>>
>>>>> I ran a relatively extensive set of benchmark configurations comparing
>>>>> CHICKEN from master against CHICKEN from master plus the patches.
>>>>
>>>> I would like to run some real-world benchmarks.
>>>> They are dynamically linked.
>>>> Would it be enough to run them with the different libchicken.so.11 versions
>>>> (before and after GC patch) or should I recompile my programs?
>>>
>>> If your binaries are dynamically linked and use a version of CHICKEN
>>> which is ABI-compatible with the code in master (ABI version 11),
>>> switching libchicken.so (e.g., via LD_LIBRARY_PATH) without recompiling
>>> your code should do the trick.
>>>
>>> If you can, please let us know about your benchmark results.
>>
>> The results for x86-64 show improvements (- 2 % run time);
>> for i586 and x32, the results show slowdowns (+ 1-2 % run time):
>>
>> GC     arch.   avg. runtime in ms
>>
>> old gc x86-64  615
>> new gc x86-64  601
>>
>> old gc x32     505
>> new gc x32     509
>>
>> old gc i586    728
>> new gc i586    739
>>
>> (My benchmark is a semantic natural language parser, which is GC-intensive.
>> C compiler is gcc 9.3.0 from Ubuntu 20.10.)
>>
>> Maybe the changes are somewhat biased for x86-64 and
>> could be adjusted for i586 and x32?
>
> Thanks for sharing your results.
>
> To be honest, the differences in your results are so small I'd flag them
> as "noise".
> Are you sure the right CHICKEN libraries were being used?

Yes. I checked it several times and ran all benchmarks at least 3 times.
For the longer run times, I also guess that this might be a random effect
of other GC settings etc.

If "x86-86" in http://parenteses.org/mario/misc/benchmarks-megane/ means
"x86-64", then you have already checked for two of the three discussed
architectures that the GC changes are improving runtime on average.
(If you have some time, maybe a comparison with x32 would be interesting.)

Greetings
Sven