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Cake day: October 14th, 2024

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  • @CameronDev I never applied the real time patch before it was integrated in 6.12, so I have no previous experience to compare to. And with 6.12, I can only go by documentation at present because the realtime configuration breaks my graphics so I have no display. But I have worked in audio studios in the past where they used it and claimed it helped. I can only take their word, but I did mention the tradeoffs earlier, if you do more context switching it is going to eat more resources, so if you are resource saturated it’s going to slow you down instead of speed you up. I am anxious for the driver issue to be resolved so I can try for myself on my hardware. I am particularly curious to see how my i9-10980xe (18 core / 36 thread) machine will respond to it. That is the machine this friendica runs on so I really need to know it’s going to be stable before I even try it, but that machine does have nvidia rather than UHD630 graphics so may work.


  • @CameronDev @thingsiplay I refer you to this: https://www.pubnub.com/blog/how-fast-is-realtime-human-perception-and-technology/

    That said, we did an experiment in a physics class many years ago where by there was a beeper and an electromagnet that were powered by the same source. The electromagnet held a yard stick in place. When the beeper went off we were supposed to push a button in response. The button stopped the fall of the yardstick. Then by calculating how far the yard stick fell using the 32m/s^2 speed of gravitational acceleration we calculated how long response was, average was about 200ms, I responsed in 30ms, however this only works for me for auditory queues, visual is more delayed for me, and I can’t detect any change in under 20ms and just barely at that, let alone respond to it. But what I learned in that class was that reaction times varied individual to individual by a factor of about ten, so what is true for one person may not be for another.




  • The 6.12 kernel UHD630 graphics worked when not compiled for realtime but just voluntary preemption. So I have filed Bug 219510. I suspect the kernel team will refer me to Intel since they actually maintain this driver, then Intel will say well it worked when the kernel people didn’t hack it for real time and it will end up going nowhere but time will tell. Without a working display, I can’t really test KVM/QEMU so will have to wait for action on this bug.


  • @thingsiplay @recursive_recursion

    With respect to gaming, the answer is a definite “maybe”. Here is the thing with a real time kernel, context switching is expensive, and especially so when going between kernel and userland mode. This is because you have to save/restore all the registers on the stack so there are a lot of memory cycles involved in a context switch. A realtime kernel increases context switching a LOT so you’re going to eat more CPU than you otherwise would but on the other hand, critical things will get attended to in a more timely manner. So whether the latency or the overall computational efficiency is more important will make the difference in gaming. Also to some degree hardware, most games will only use 4 cores or so, a few more than that but most only about 4, so if you’ve got an 18 core machine, you have plenty of core for the extra kernel overhead, it is more likely to benefit than if you’re on a 4-core machine with all the cores already saturated.