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by nanis 3488 days ago
Just to make sure: You built all binaries and linked libraries yourself, from scratch, with the same optimization settings, right?
1 comments
erichileman 3488 days ago
The binaries are from remi repo. We have a template we provision from. I used the same template on each virtual machine.

PHP 5.4.45 (cli) (built: Sep 19 2016 15:31:07) PHP 5.5.38 (cli) (built: Nov 9 2016 17:32:11) PHP 5.6.28 (cli) (built: Nov 9 2016 07:04:38)

The binaries are the same on each virtual machine. Are there build optimizations for E3/V5 vs E5/V2 that could make such a difference?

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cthalupa 3488 days ago
>Are there build optimizations for E3/V5 vs E5/V2 that could make such a difference?

Potentially, yes.

Either way you're not comparing apples to apples using packages from a 3rd party repo built for a different system.

Newer processors have different instruction sets (AVX is a big one). You'd want to make sure you're not only compiling it on each different platform, but also using a new enough compiler to support the instruction sets.

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erichileman 3488 days ago
Correct. We are going to build using the correct -march flags: https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html
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erichileman 3488 days ago
>>gcc -march=native -Q --help=target

>>march=silvermont

gcc native thinks this e3 is silvermont, a low power SoC.

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erichileman 3487 days ago
We built 5.6 with -O2 -march=broadwell -mno=avx (had to remove, probably pecl ext issue).

There was about a 15% performance gain. Nothing that would explain the large difference between E3 and E5.

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erichileman 3488 days ago
Found this and will try it: https://github.com/centminmod/centminmod/commit/755dd9e87eac...
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