Linux 6.5 Final Minute Fixes A Efficiency Regression – 34% Drop In A Micro-Benchmark
Whereas Linux 6.5 is expected for release tomorrow, the circulation of final minute fixes is not over.
Despatched out immediately had been some x86 fixes for Linux 6.5 Git forward of its last tagging — or Linux 6.5-rc8 if Linus Torvalds decides to pull out the discharge by an additional week. Making the weekend pull request notable is that it has a repair for a efficiency regression because of a lacking set of X86_FEATURE_OSXSAVE.
The patch addressing the difficulty explains that Intel’s 0-day testing of the Linux kernel uncovered a 34.6% efficiency regression. The offender comes right down to lacking a easy two traces of code for checking and setting X86_FEATURE_OSXSAVE earlier within the boot course of.
It is a regression for simply new code launched in the course of the Linux 6.5 merge window. Introducing the regression was the Linux 6.5 change for delaying x86 FPU initialization as part of cleaning up the boot process. Intel’s kernel take a look at robotic reported the regression in mid-July but it surely wasn’t till immediately {that a} repair labored its option to the mainline kernel.
This 34.6% efficiency regression was uncovered by the stress-ng af-alg take a look at case (exercising the AF_ALG socket area) as a micro-benchmark however nonetheless not less than this was not less than noticed and fixes forward of the seemingly Linux 6.5 secure debut tomorrow.