Looking at the text log, the results are a bit strange and I can't
easily explain it. Normally a system interrupt would increase the time
taken.
Let me know if increasing the iteration count fixes it or not.
Kit
On 10/10/2023 09:57, Tomas Hajny wrote:
On 2023-10-09 20:51, J. Gareth Moreton via fpc-devel wrote:
Hi Kit,
I updated the "blea" test in the merge request so it now displays the
processor brand name on x86_64; however, it is not fetched under i386
because CPUID was not introduced until later 486 processors. I've
attached it to this e-mail if anyone wants to take a look to ensure I
haven't broken something.
I don't know what's broken, but the results vary so much on a fast
machine that they are unusable for any measurement from my point of
view (standard 3.2.2 compiler, compiled with -O4 and running under MS
Windows this time). Sometimes the ADD version shows 0.0 ns/call,
sometimes the LEA version shows 0.0 ns/call (32-bits) or 0.1 ns/call
(64-bits). See the attached results (the CPU is only displayed for the
64-bit compilation, but it's obviously the same CPU).
Tomas
On 09/10/2023 18:01, J. Gareth Moreton via fpc-devel wrote:
Thank you very much! That processor is built on the Excavator
architecture and lines up with the flag I put in the merge request
(i.e. it has the "fast LEA" hint).
I honestly didn't expect this much testing feedback, so thank you all!
Gareth aka. Kit
P.S. I'm tempted to extend the test slightly to actually name the
CPU automatically.
On 09/10/2023 15:40, Jean SUZINEAU via fpc-devel wrote:
My results:
jean@First-Boss:~/temp$ cat /proc/cpuinfo | grep "model name"
model name : AMD A6-7480 Radeon R5, 8 Compute Cores 2C+6G
jean@First-Boss:~/temp$ /usr/bin/fpc blea.pp
Free Pascal Compiler version 3.2.2 [2021/07/09] for x86_64
Copyright (c) 1993-2021 by Florian Klaempfl and others
Target OS: Linux for x86-64
Compiling blea.pp
Linking blea
95 lines compiled, 0.2 sec
jean@First-Boss:~/temp$ ./blea
Pascal control case: 5.1 ns/call
Using LEA instruction: 0.5 ns/call
Using ADD instructions: 0.8 ns/call
jean@First-Boss:~/temp$
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