With the great performance gains found out of the Intel Core Ultra X7 358H when manually enabling FRED via the fred=on kernel parameter, it was puzzling that this wasn't enabled by default especially with Panther Lake laptops now shipping for the past two months. Intel engineers squared away the rest of the FRED support for the Linux kernel a while ago and given the significant performance benefit it's baffling that it wasn't enabled pre-launch. The past last week though characterized the non-default state as waiting on production hardware for validating the performance impact and ensuring no regressions.
"When FRED was added to the mainline kernel, it was set up as an explicit opt-in due to the risk of regressions before hardware was available publicly.
Now, Panther Lake (Core Ultra 300 series) has been released, and benchmarking by Phoronix has shown that it provides a significant performance benefit on most workloads:
https://www.phoronix.com/review/intel-fred-panther-lake
Accordingly, enable FRED by default if the CPU supports it. FRED can of course still be disabled via the fred=off command line option."
The news today is that the patch has been queued into tip/tip.git's x86/fred Git branch . With the patch now in a TIP branch, it should be submitted for the Linux 7.1 merge window happening in April following the Linux 7.0 stable release. Too bad this wasn't sorted out in time for the Linux 7.0 kernel merge window so it would be the default in the likes of Ubuntu 26.04 LTS, but at least it happened now in time for v7.1.
So look for better performance with Panther Lake and future Intel CPUs plus AMD Zen 6 with Linux 7.1+ with FRED being enabled by default. Those on Panther Lake with recent kernel versions can still boot for now with fred=on to enjoy the added performance of Flexible Return and Event Delivery.