diff options
Diffstat (limited to 'kernel/Kconfig.preempt')
| -rw-r--r-- | kernel/Kconfig.preempt | 58 |
1 files changed, 56 insertions, 2 deletions
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt index bf82259cff96..c2f1fd95a821 100644 --- a/kernel/Kconfig.preempt +++ b/kernel/Kconfig.preempt @@ -1,11 +1,23 @@ # SPDX-License-Identifier: GPL-2.0-only +config PREEMPT_NONE_BUILD + bool + +config PREEMPT_VOLUNTARY_BUILD + bool + +config PREEMPT_BUILD + bool + select PREEMPTION + select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK + choice prompt "Preemption Model" default PREEMPT_NONE config PREEMPT_NONE bool "No Forced Preemption (Server)" + select PREEMPT_NONE_BUILD if !PREEMPT_DYNAMIC help This is the traditional Linux preemption model, geared towards throughput. It will still provide good latencies most of the @@ -20,6 +32,7 @@ config PREEMPT_NONE config PREEMPT_VOLUNTARY bool "Voluntary Kernel Preemption (Desktop)" depends on !ARCH_NO_PREEMPT + select PREEMPT_VOLUNTARY_BUILD if !PREEMPT_DYNAMIC help This option reduces the latency of the kernel by adding more "explicit preemption points" to the kernel code. These new @@ -38,8 +51,7 @@ config PREEMPT_VOLUNTARY config PREEMPT bool "Preemptible Kernel (Low-Latency Desktop)" depends on !ARCH_NO_PREEMPT - select PREEMPTION - select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK + select PREEMPT_BUILD help This option reduces the latency of the kernel by making all kernel code (that is not executing in a critical section) @@ -80,3 +92,45 @@ config PREEMPT_COUNT config PREEMPTION bool select PREEMPT_COUNT + +config PREEMPT_DYNAMIC + bool "Preemption behaviour defined on boot" + depends on HAVE_PREEMPT_DYNAMIC && !PREEMPT_RT + select JUMP_LABEL if HAVE_PREEMPT_DYNAMIC_KEY + select PREEMPT_BUILD + default y if HAVE_PREEMPT_DYNAMIC_CALL + help + This option allows to define the preemption model on the kernel + command line parameter and thus override the default preemption + model defined during compile time. + + The feature is primarily interesting for Linux distributions which + provide a pre-built kernel binary to reduce the number of kernel + flavors they offer while still offering different usecases. + + The runtime overhead is negligible with HAVE_STATIC_CALL_INLINE enabled + but if runtime patching is not available for the specific architecture + then the potential overhead should be considered. + + Interesting if you want the same pre-built kernel should be used for + both Server and Desktop workloads. + +config SCHED_CORE + bool "Core Scheduling for SMT" + depends on SCHED_SMT + help + This option permits Core Scheduling, a means of coordinated task + selection across SMT siblings. When enabled -- see + prctl(PR_SCHED_CORE) -- task selection ensures that all SMT siblings + will execute a task from the same 'core group', forcing idle when no + matching task is found. + + Use of this feature includes: + - mitigation of some (not all) SMT side channels; + - limiting SMT interference to improve determinism and/or performance. + + SCHED_CORE is default disabled. When it is enabled and unused, + which is the likely usage by Linux distributions, there should + be no measurable impact on performance. + + |