[fpc-devel] Curious about the effect of all the new optimizations....

Martin Frb lazarus at mfriebe.de
Wed Mar 1 14:35:11 CET 2023

On 01/03/2023 14:22, J. Gareth Moreton via fpc-devel wrote:
> On 01/03/2023 13:11, Martin Frb via fpc-devel wrote:
>> Hence testing back to  3.2.3 ( unfortunately 3.2.2 has a bug that 
>> matters in this code)
>> Also, I didn't expect any huge diffs, just wanted to see if anything 
>> can be noted at all. (and if lucky, in that test I run)
>> I did a test on a more limited scope (testing only a handful of 
>> functions. That test runs 4 Min 20 sec under 3.2.3.
>> And 2 extra seconds with 3.3.1.  But then I only had 2 sample runs 
>> for each fpc version....
> 2 seconds out of 4:20 is not conclusive unfortunately, unless you're 
> able to exactly control the machine state each time, which is next to 
> impossible in the modern day.  I am curious of the slowdown though, 
> even if it is very slight.
It will be to much code to find it....

It's looping and setting up different combinations of data/structures...

It is the test in ide/packages/idedebugger
subtest: TestWatchArrayStuct
(I did not check the others subtests, but this test is combining some of 
the others...)

The diff also happened when I did (for some of the involved units / not 
for all)
{$CodeAlign proc=32 loop=32}

But it could still be that some code got to an unfortunate alignment.

For more testing I would need to set up scripts, to compile and run 
automatically with lots of settings (and then run over night, when 
nothing else goes on).
Also find other PC with diff CPU ....

For now, I just wanted to do a quick test. (balance my interest with the 
time I have...). So I wont set up in depth testing now.

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