Intel's Clear Linux Taps -O3 For Its Kernel Builds

Written by Michael Larabel in Clear Linux on 12 August 2022 at 05:50 AM EDT. 49 Comments
While Intel's performance-optimized Clear Linux rolling-release distribution is known for its aggressive performance optimizations, their kernel build had been going with the default "-O2" optimization but last week did switch over to rolling their kernel with -O3.

The upstream kernel has dropped the dedicated -O3 option but higher optimization levels can still be passed to the kernel via the compiler flags, which is what Clear Linux is doing.

Following a ticket about having the kernel built with the higher -O3 optimization level, Clear Linux's kernel package has switched to -O3 for hopefully juicing a bit more out of the kernel.

Granted, from my own recent -O3 kernel build benchmarks, most kernel-sensitive workloads tended to have just minor gains if at all. In any case it will be interesting to see how well the -O3'ed kernel works for Clear Linux on top of all their other speed optimizations for maximizing Linux x86_64 performance. Meanwhile their kernel "-march=" target continues to be Westmere as at the bottom end of their Intel hardware support spectrum.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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