Intel recently released a one-line code patch for its Meteor Lake CPUs, resulting in huge performance wins in Linux. That single line of code fine-tunes the P-State CPU frequency scaling driver. In benchmark tests, the seemingly minor change resulted in Linux performance increases as high as 72% on Intel's Core Ultra PC systems.
The patch, sent out on June 6, 2024, adjusts the Intel P-State Energy Performance Preference (EPP) default “balance_performance” value. This sets the balance between power and performance in a processor. The allowable range for the EPP is from 0 to 255 and it was set to 128 in February before Intel changed it to 115. The latest patch further refines the value from 115 to 64.
Initial testing of the change showed up to 19% better performance on the Meteor Lake processors and up to 11% improvement in performance per watt. Michael Larabel at Phoronix decided to conduct some more extensive benchmark tests to determine how much better the Meteor Lake CPU could perform after the single-line patch.
Testing was conducted using an Acer Swift Go 14 with the Intel Core Ultra 155H running the current Linux 6.10 kernel. Larabel ran benchmarks pre-update, then applied Intel’s patch to the kernel and reran the same tests. He performed more than 100 benchmarks testing the patch and found the change yielded an improvement of 7% to the geometric mean across all tests.
Most notably, the Kvazaar 2.2 Bosphorus 4K video encoding benchmark with a preset of Super Fast blazed through at 20.51 frames per second with the patch. Without the patch, encoding happened at 11.94 fps. Hence, the one line of changed code resulted in an improvement in video encoding of 72% with the Meteor Lake laptop. Other video encoding benchmarks were also improved, but not as dramatically.
The least impressive performance increase observed was in Python testing, coming in at just a 2% uptick with the patch applied. Still, any increase is better than none, and the overall improvement can be appreciated by anybody trying to get the most out of their Meteor Lake processor. Larabel hopes the patch will be included in the Linux 6.11 Git kernel, if not applied as a maintenance fix for the current Linux 6.10 cycle.
