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RHEL9 Raises Base Target For x86_64 CPUs Plus Possible Optimized Libraries With glibc-hwcaps

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  • #11
    Originally posted by ms178 View Post

    This move is the first in a long time where it becomes clear that ISA support matters, and that it matters a lot. Tons of reviewers did get that wrong at that time when recommending these cheap Pentium G CPUs, suggesting that AVX-support wouldn't matter that much, and while this was true at that point in time, it turned out to be of more significance now. Intel's market segmentation on the ISA-level hurts them now, but more so users who were either not paying attention or were picking a CPU without taking ISA support into account as there were AMD alternatives with these features at that time in this price range, and these AMD users are now better off with OS support.
    A lot of reviewers are targeting gamers, not people using computers in production.

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    • #12
      Originally posted by ms178 View Post
      Thanks for defining these new feature levels, it helps to move things forward and I hope it will even translate into the Windows world.
      One of the challenges for Microsoft may be their previous spin that Windows 10 is last consumer version of Windows, and they will just offer feature updates from now on and build on that base with HWE updates for newer systems. I suppose they could try to thread the needle and create a consumer Windows 10++ version that required something like Sapphire Rapids or better processors, but it seems more likely they will add in the equivalent of hwcaps.

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      • #13
        I know my 4 year old atom based HTPC has no AVX but I am looking to upgrade that to Van Gough once some one releases a mini PC with one.

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        • #14
          Originally posted by zxy_thf View Post

          A lot of reviewers are targeting gamers, not people using computers in production.
          Sure, but even they should at least mention the lack of these instructions so that people are aware of the drawbacks. People who care about longevity should have looked to other SKUs or the competition anyways.

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          • #15
            Originally posted by ms178 View Post
            As AMD usually lacks behind Intel in ISA-support, I'd say not having AVX-512 support now could hurt AMD users down the road tomorrow. I would have thought that they would bring it to AM4 with Zen 3, but they did not. We know now what that means for Zen 3 users as Zen 4 is rumored to get AVX-512 support, that is the next CPU to get for better long-term value....
            in my knowledge a 5950X has AVX512 emulation based on microcode on AVX256 hardware.
            means your thoughts are wrong AMD customers will not be hurt by AVX512 ISA.
            AVX512 is a death horse right now AMD will not implement it in hardware but they already implemented it in software emulation run on AVX256 hardware.
            Phantom circuit Sequence Reducer Dyslexia

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            • #16
              Originally posted by zxy_thf View Post

              A lot of reviewers are targeting gamers, not people using computers in production.
              They would be would have been wise not to say that even for gaming in the last few years. Last year Destiny 2, Apex Legends, and Star Citizen at least were all requiring AVX and unpleasantly surprising would-be customers in the process (or in Star Citizen's case, current customers).

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              • #17
                Originally posted by Qaridarium View Post

                in my knowledge a 5950X has AVX512 emulation based on microcode on AVX256 hardware.
                means your thoughts are wrong AMD customers will not be hurt by AVX512 ISA.
                AVX512 is a death horse right now AMD will not implement it in hardware but they already implemented it in software emulation run on AVX256 hardware.
                I haven't heard any of this, AMD also doesn't explicitly support AVX-512 with Zen 3. By the way, AVX-512 was designed to be more multi-purpose friendly, and Matt Pharr, the original author of ISPC, thinks that it is a huge improvement. As more and more game engines make use of ISPC (such as the next EA and Unreal Engine), AVX-512 support will deliver these improvements to capable CPUs. The old mantra that AVX doesn't matter in games is about to change (ISPC makes good use of SSE on older CPUs, too. But there might be a performance delta where the newer ISAs provide huge benefits).

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                • #18
                  Originally posted by ms178 View Post

                  I haven't heard any of this, AMD also doesn't explicitly support AVX-512 with Zen 3. By the way, AVX-512 was designed to be more multi-purpose friendly, and Matt Pharr, the original author of ISPC, thinks that it is a huge improvement. As more and more game engines make use of ISPC (such as the next EA and Unreal Engine), AVX-512 support will deliver these improvements to capable CPUs. The old mantra that AVX doesn't matter in games is about to change (ISPC makes good use of SSE on older CPUs, too. But there might be a performance delta where the newer ISAs provide huge benefits).
                  you do a lot of advertisement for AVX512... nothing what you write in the benefit of intels AVX512 is true. why?
                  simple to much power consumtion and the need to downclock the core if the AVX512 unit is used.
                  your so called 5,2ghz 11900K turned into a 1,7ghz cpu if you use AVX512.
                  and if you have mixxed workload this decrease the integer performance very much and 80% of all code used is integer.

                  AMDs cpu design in the past used the SIMD 128bit units of 2 cores to emulate AVX256bit
                  and they design to use 2 simd 256bit units to emulate AVX512...

                  it is clear AMD will not support AVX512 per core because clock speed is to low.

                  the AVX units from AMD do not need to downclock it run at full ~4,5ghz...

                  compare it to car engine AVX512 is full 8L engine per core and AMD cpu cores are only downsizing useing one 3L engine with turbo and the AVX units of 2 cores can work together.

                  AMD is very successfull with this downsitzing strategy no need for AVX512 at all.
                  Phantom circuit Sequence Reducer Dyslexia

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                  • #19
                    Originally posted by Qaridarium View Post

                    you do a lot of advertisement for AVX512... nothing what you write in the benefit of intels AVX512 is true. why?
                    simple to much power consumtion and the need to downclock the core if the AVX512 unit is used.
                    your so called 5,2ghz 11900K turned into a 1,7ghz cpu if you use AVX512.
                    and if you have mixxed workload this decrease the integer performance very much and 80% of all code used is integer.
                    This is an implementation detail which is becoming less true with newer generations on Intel CPUs. Also this doesn't mean that this will be an issue with upcoming AMD CPU's. There are workloads where in spite of the downclocking, the benefits are still noticeable. These workloads are the last hold outs where Intel still trumps AMD in benchmarks. These might not be relevant to many people, but they are for some.

                    Originally posted by Qaridarium View Post
                    AMDs cpu design in the past used the SIMD 128bit units of 2 cores to emulate AVX256bit
                    and they design to use 2 simd 256bit units to emulate AVX512...
                    Let's wait and see how AMD will implement it this time, while being good enough for most use cases at that time, this implementation strategy had its drawbacks, Intel's AVX2 implementation was faster where it was utilized fully. There is a chance for AMD to implement AVX-512 better than Intel though, without downclocking. AMD always hinted: We will implement it when the cost (die size) is reasonable and when they could avoid the downclocking, and with each newer process node these issues fade away. They originally wanted these workloads to be shifted onto the GPU - I don't know if you've noticed, but their HSA efforts failed, as this programming model never got wide enough traction and OpenCL versions above 2.0 haven't gotten any traction in the industry either.

                    Originally posted by Qaridarium View Post
                    AMD is very successfull with this downsitzing strategy no need for AVX512 at all.
                    At least Matt Pharr thinks differently, but he could make use of AVX-512 to a bigger extend, the speedups he achieved speak for themselves which showed good scaling in both vectorization and parallelization even in code which wasn't suited for this. He argued that from a performance per area perspective, wider vector engines were superior than putting more cores on the die. AMD went the opposite route with much success, but that is to a large part only reflecting Intel's inability to strike back on newer process nodes during the last several years. We are still stuck on a refined Skylake architecture on the desktop with Intel today. If they had kept innovating as they should have, AMD would have had a harder time coming back into the market. Also Intel failed for a long time to push software more to make better use these advanced capabilities of their CPUs, it took ages until RedHat finally drove this x86-feature level thing, why hasn't Intel done so already 5-10 years ago?

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                    • #20
                      Originally posted by phoronix View Post
                      Phoronix: RHEL9 Raises Base Target For x86_64 CPUs Plus Possible Optimized Libraries With glibc-hwcaps

                      As we reported almost one year ago, Red Hat was looking at likely dropping older x86_64 CPU support from Red Hat Enterprise Linux 9 and we now have a better idea of their plans in catering RHEL9 better to modern processors...

                      http://www.phoronix.com/scan.php?pag...86-64-v2-Plans
                      who is " Red Hat " Michael? its all 1 word REDHAT

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