nsd users - Jul 2024 - Run-time effects of new SIMD code

Hi NSD developers,

I've been following recent discussion and activity around building NSD
4.10, triggered by build failure in Homebrew. I see that you added some
code to detect more things and adjust the build based on what type of
processor is detected.

If one were to build NSD on an x86_64 CPU with Haswell architecture, and
then run this build on another x86_64 CPU that doesn't have that
architecture, will NSD not run, or will it crash, or will it silently use
sub-optimal code?

Regards,
Anand
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On 2024/07/17 15:47, Anand Buddhdev via nsd-users wrote:
> Hi NSD developers,
> 
> I've been following recent discussion and activity around building NSD
4.10, triggered?by build
> failure in Homebrew. I see that you added some code to detect more things
and adjust the build
> based on what type of processor is detected.
> 
> If one were to build NSD on an x86_64 CPU with Haswell architecture, and
then run this build on
> another x86_64 CPU that doesn't have that architecture, will NSD not
run, or will it crash, or
> will it silently use sub-optimal code?
Looking at the code, it's using runtime detection based on checking
cpuid results, so it should use whatever is the most optimal for the cpu
on the machine where it runs.