Ubuntu benchmarks

Linux 5.19-rc7 released after a rough week with Retbleed, Intel GPU Firmware Snafu

Linus Torvalds just released Linux 5.19-rc7 after a busy week due to the rebleed security limitation and not only the impact of CPU overhead performance on users, but also the mess it has on kernel development, especially when it comes to embargo issues that make it difficult to properly review/test the patches before launching. embargo …

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Retbleed: Call Depth Tracking Mitigation Eyed To Avoid IBRS “Performance Horror Show”

Through the new “Retbleed” security limitation that further hurts CPU performance for affected processors, Intel engineers have rethought work on call depth throttling as an alternative to indirect industry throttling (IBRS) mitigation to reduce overhead costs. Thomas Gleixner of Linutronix, who Intel acquired earlier this yearand longtime Intel engineer Peter Zijlstra have been working on …

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Benchmarking Linux’s Degraded Performance for Retbleed: It’s Painful

Yesterday rebleed was made public as a new speculative execution attack using return statements. While the “good” news is that Retbleed only affects previous generations of AMD and Intel processors, the bad news is that the reduced performance impact on Linux is pretty serious. Since yesterday I’ve been benchmarking the newly merged Linux patches on …

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Final comment from Linus Torvalds against -O3’ing of the Linux kernel

This shouldn’t be too surprising given Linus Torvalds’ previous commentary about compiler optimizations and bad experiences long ago with GCC, but Linus Torvalds isn’t interested in a tunable Kconfig option for using the -O3 compiler optimization level for building the Linux kernel without substantial justification. As I wrote earlier this week there was a proposed …

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