AMD engineer K Prateek Nayak recently uncovered that a 20 year old chipset workaround in the Linux kernel still being applied to modern AMD systems is responsible in some cases for hurting performance on modern Zen hardware. Fortunately, a fix is on the way for limiting that workaround to old systems and in turn helping with performance for modern systems. Phoronix reports: Last week was a patch posted for the ACPI processor idle code to avoid an old chipset workaround on modern AMD Zen systems. Since ACPI support was added to the Linux kernel in 2002, there has been a “dummy wait op” to deal with some chipsets where STPCLK# doesn’t get asserted in time. The dummy I/O read delays further instruction processing until the CPU is fully stopped. This was a problem with at least some AMD Athlon era systems with a VIA chipset… But not a problem with

  • https://hardware.slashdot.org/story/22/09/26/2145237/a-20-year-old-chipset-workaround-has-been-hurting-modern-amd-linux-systems?utm_source=rss1.0mainlinkanon&utm_medium=feed
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  • post author: BeauHD

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