On Thu, Mar 21, 2024 at 6:07 PM Samuel Sieb <samuel(a)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(a)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