On Thu, Mar 21, 2024 at 6:07 PM Samuel Sieb samuel@sieb.net wrote:
On 3/21/24 14:45, Stephen Morris wrote:
On 22/3/24 00:18, Barry wrote:
On 20 Mar 2024, at 22:19, Stephen Morris samorris@netspace.net.au wrote:
Just a couple of silly questions: AVX cpu's, both Intel and AMD, have been around since 2008, and this is 2024, why does Fedora not have support for the AVXx instruction sets?
Not all recent CPUs have AVX, only some CPUs I believe. Therefore the preference for detect at runtime.
I can understand the runtime detection, but why is pygame, presumably with its support for vectors, not compiled to use AVX if available. The math module doesn't produce the message, even though AVX can be used with integer manipulations, does that mean it has been compiled with AVX support or is it not checking for support? With, in this case, the pygame module having been installed from the Fedora repositories and producing this issue, does that mean I shouldn't install the modules from the Fedora repositories, I should use pip3 to install the modules as they may be compiled with AVX support? The message I got indicated that my cpu supports AVX2, how do I determine if it supports AVX512?
The message is about AVX2, not AVX. The computer I'm currently using is an Intel Xeon from 2019 or maybe a bit earlier. It has AVX, but not any of the higher ones.
It is common to see manufacturers of low-end tablets and pc's buying cpu's from Intel that only have SSE2-SSE4.1+AES+RDRAND enabled. I encounter them regularly in low-end netbooks. The cpu's probably have higher ISAs, they just are not enabled.
Intel will also de-clock or slow down the cpu for the price point. I was talking to David Johnson, who designed Intel's RDRAND circuit. He told me intel can tune about 100 different parameters to vary cpu features and speeds for a particular price point.
You can look in /proc/cpuinfo to see the flags, or install "cpuid" to get very detailed information.
Jeff