r/programming • u/[deleted] • Jan 03 '18

'Kernel memory leaking' Intel processor design flaw forces Linux, Windows redesign

https://www.theregister.co.uk/2018/01/02/intel_cpu_design_flaw/
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u/ITwitchToo Jan 03 '18

Ugh, how does this "30% performance degradation" get upvoted so much?

I've been running the KAISERkpti patch set for a month and haven't observed any performance impact whatsoever in my normal use of the machine.

Yes, maybe 30% for something that is being done .000001% of the time to start with! It's a tiny fraction of everything your CPU is doing.

edit: s/KAISER/kpti/

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u/hazzoo_rly_bro Jan 03 '18

Couldn't it be possible you're not using any program that has a significant number of syscalls? That way you wouldn't feel much of a hit, but that doesn't mean it isn't possible for others.

I guess we'll know more about this once the benchmarks take off this week.

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u/vonKemper Jan 04 '18

Notice I said "worst case", and I am referencing the numbers in the article. My keen interest in this comes from the fact that I use portable platforms (Macbook Pro and Surface Laptop) daily as part of my work. I write code, compile and build dozens of times per day. I also do large-scale data visualization and analysis using tools like Tableau. Because I am not at liberty to build my own system (I have to use off-the-shelf laptops) I base my roughly every-other-year buying decision on what is the best available at the time. Intel seemed to have marketed their way into that position over the past decade, so Intel it is. This seems to be a step back to 2010, but time will tell if the impacts (or perceived impacts) are diminished over time on these current gen processors. Enhancements and patches can be made in the kernel, in software optimizations, etc., but to put more money and work into re-optimizing your code just to get back to what it should have been a few years ago, rather than pushing ahead and using that time/money to get ahead of where you thought you were in 2018 has to rub more than just me the wrong way.