POWER CPUs Ready With Dynamic Preemption For Linux 6.16
Merged for Linux 5.12 back in early 2021 was a new dynamic preemption mode. Finally now for H2'2025, the IBM POWER CPU ISA kernel code is supporing dynamic preemption.
The CONFIG_PREEMPT_DYNAMIC option when enabled allows setting preempt= at boot time to either none/voluntary/full with full preemption being the default. Distributions can still set the standard PREEMPT controls but this dynamic option allows changing it at boot time without rebuilding the kernel or even at run-time via DebugFS. The kernel relies on run-time patching for changing the kernel preemption mode on the fly.
The POWER/PowerPC code for Linux 6.16 is picking up support for dynamic preemption. There is also enablement of a new PMU for KVM host-wide measurement and various other minor fixes and improvements.
More details on these POWER changes for Linux 6.16 via this pull request.
The CONFIG_PREEMPT_DYNAMIC option when enabled allows setting preempt= at boot time to either none/voluntary/full with full preemption being the default. Distributions can still set the standard PREEMPT controls but this dynamic option allows changing it at boot time without rebuilding the kernel or even at run-time via DebugFS. The kernel relies on run-time patching for changing the kernel preemption mode on the fly.
The POWER/PowerPC code for Linux 6.16 is picking up support for dynamic preemption. There is also enablement of a new PMU for KVM host-wide measurement and various other minor fixes and improvements.
More details on these POWER changes for Linux 6.16 via this pull request.