First hit for me for avx2. Great video too.

Glad you enjoyed! It’s admittedly a pretty niche programming concept.

@@ProceuTech That it is, I had it on the list of things I dont fully understand

The other Avx video I made more recently is a much better video than this one if you want better info- appreciate the support tho!

Let me do some coding real quickly and do some tests. I’ll get back to you in a few minutes!

Ok so I just reran the function in order to see what was actually going on in the array. Turns out it wasn’t returning proper values! Thanks for catching that! I’m so used to working with vectors (which can be returned), and don’t have as much experience with arrays. Sorry for the confusion!

@@ProceuTech Thanks for clearing up my doubt! At least I know that it is possible to return a local vector in C++.

Vectors can still be processed using AVX aswell- you just have to use “_mm512_set_ps(i[0], i[1], etc., i[15]);”, which takes up more space in your program but offers identical performance!

@@ProceuTech With std::vectors, you can just use i.data(), which is the pointer to the internal array. As for returning AVX values, you can just return __m512 directly, or populate a std::vector via data() and return it.

Well AVX is very demanding, so the CPU uses a lot of power when executing AVX heavy instructions. And of course more power = more heat. Burn in apps like Prime95 I believe use or have the option to use AVX/AVX512 during the burn in test to really push the CPU as hard as possible. As for causing a CPU to overheat. Not it should not do that if you have a stable setup.

no more than normal. Volatile is for when something (like another thread) might possibly modify the memory of a variable without the knowledge of the current thread, so the compiler should treat it as a volatile (subject to unpredictable change) value and re-read it whenever it needs to use it, and not assume it's value will stay the same if it hasn't changed it which prevents certain compiler optimisations that would assume the value is unchanging. AVX memory reads and writes happen in a single cycle like normal register reads and writes so there's no real difference. should also be noted there are no "locked" versions of AVX instructions, so if you are trying to operate on vector data with multiple threads, you should work out some other way to prevent race conditions, like data segmentation or mutexes (preferably with lock elision since the hardware memory synchronization involved in locks/mutexes is quite slow)

Some implementations have a toggle where you can switch between AVX and “Non-AVX” algorithms. Not all of them have this though :(

Is there an explanation as to why?

@@ProceuTech The first program to load a file from disk pays a time penalty for the disk I/O operations; however, the OS then keeps as much of that file in the system RAM as possible and some of the file even resides within the fast cache of the CPU itself. The next program you run which needs to read that file will retrieve the data very quickly from the CPU cache and system RAM. So that second program doesn't pay the same time penalty for disk I/O operations.

@@mkvalor I have a problem understanding what you mean by the loading from disk. When the program is loaded those values are going straight into RAM. When the variables got initialised they get pushed onto the stack. When the AVX function is called all that happens is the address of a gets copied into the RAX register, and the address of b gets copied into RDX. The exact same thing happens when we run the linear function. Are you suggesting that the page containing this tiny program gets unloaded mid-execution?

For sure there's a lot wrong with the test. first, the input data is unchanging, so the compiler should optimize out the loop entirely, or maybe just the memory reads. but this would also almost completely invalidate your argument about caching - which would be valid if the test actually had a significant volume of data and was storing the result somewhere. As someone already noted, though, the compiler may well have used vector instructions for the simple loop as well - more likely with clang I think - giving the somewhat poor showing of 70% speedup. It would all depend on compiler flags for optimization level and target architecture. If it didn't optimize everything well, then there may instead be a whole lot of overhead from the function calls and extra memory reads/writes involved. If I were to write assembler code to do what is presented in this test (on multiple data) it wouldn't take 80µs on a 5Ghz CPU. afaik these CPU's are capable of 2 reads 1 add and 1 write per clock, even at 512bit, so the whole process should take < 1µs with avx512 instructions. even with scalar instructions (which still execute on the vector alu, just through 1 channel) it should have happened in 15µs - slowed from 8µs only by the scalar reads of memory. to get a more reliable result, probably a significant chunk of data, and >1000000 iterations would be needed - and likely 100's of repetitions of the whole process to account for variations of CPU load, clock frequency (OS usually keeps clocks low till something starts happening - but it takes a few ms for it to respond), interrupting operations etc. and check the disassembly to be sure of what is being executed.

@treelibrarian7618 I made an updated video with this information in it; the tests done in this video were flawed

Yeah this video is honestly not great- check out my more recent AVx video if you want to look into the syntax more deeply! I explain it way better and without any of these goofy mistakes on my end

The 11700F! The 10700F only features AVX2!

@@ProceuTech Is 11700F the same as 11700? I know the F doesnt have iGPU , but does the iGPU help with AVX512???

No, AVX-512 units are in the CPU cores themselves!

I've also got a video exploring CUDA and it's syntax- it's much more well put together in my opinion than this video! :)

The more recent video I made about AVX512 (linked in the first few seconds of the video) explain the concept and program much better

I have another AVX video that goes more in depth as to what the instruction set entails, as well as a better guide on programming for it. Might be worth a watch if you’re confused!

As for AVX hindering performance. I'm not a programmer. My only guess is maybe the "AVX offset" a lot of motherboards have where it downclocks the CPU by some amount when using AVX (though I'm pretty sure that can be turned off on most motherboards). As for AVX being a problem because of compatibility, I guess if you have a really old CPU. On the latest Steam hardware survey (June 2024), 97% of steam users have a PC that support AVX. From what I understand Intel and AMD started shipping CPU's with AVX support in 2011.

Then don't watch them?