Linux could leave Windows 11 in the dust as Intel hybrid CPUs get further optimizations

Back at its Architecture Day 2021 event, when Intel shared the core design details of its Alder Lake CPU architecture, the firm stated that Windows 11 was optimized in a way to best take advantage of the Alder Lake's Performance Hybrid architecture and the new Thread Director technology that helps Windows 11 task scheduling.

Following this announcement, head to head testing back in November 2021, indeed showed Windows 11 outperforming Linux quite easily thanks to the special optimizations baked into Microsoft's new OS. In fact, it was beating out Windows 10 too, even when using an older Lakefield CPU.

Fast forward to August of 2022 and things are looking quite different than they were previously. Linux has since been optimized further with changes made under the hood to close the gap with Windows 11. The latest test on Ubuntu using Linux kernel version 5.18 shows an Alder Lake-S Core 19-12900K being barely any worse than when compared to a Windows 11 system.

However, further optimizations are still being done according to a new patch by Intel's Linux engineer Ricardo Neri. The new patch basically talks about improving task scheduling between the Bigger P-cores (performance cores) and the Bug E-cores (efficiency cores).

On processors with a mixture of higher-frequency SMT cores and lower- frequency non-SMT cores (such as Intel hybrid processors), a lower- priority CPU pulls tasks from the higher-priority cores if more than one SMT sibling is busy.

Do not use different priorities for each SMT sibling. Instead, tweak the asym_packing load balancer to recognize SMT cores with more than one busy sibling and let lower-priority CPUs pull tasks.

Removing these artificial priorities avoids superfluous migrations and lets lower-priority cores inspect all SMT siblings for the busiest queue.

With this Linux can potentially leave Windows 11 in the dust depending on the kind of improvements the new optimization sees. Besides it will be beneficial either way since Intel's upcoming 13th Gen Raptor Lake as well as future 14th Gen Meteor Lake CPUs will all be employing the same Performance Hybrid-based design.

Via: Phoronix