Messages in this thread Patch in this message | | | Date | Fri, 20 Oct 2023 15:40:42 +0200 | From | Emanuele Rocca <> | Subject | Re: Runtime overhead of PREEMPT_DYNAMIC |
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Hi Mike,
On 2023-10-20 02:42, Mike Galbraith wrote: > It's kinda hard to imagine the author's mailbox surviving submission > day were it _that_ horrid, surely something is amiss.
Thanks for trying to reproduce! Let's see if we can find out what's wrong in my setup then.
> voluntary (my usual) > CONFIG_PREEMPT_VOLUNTARY_BUILD=y > # CONFIG_PREEMPT_NONE is not set > CONFIG_PREEMPT_VOLUNTARY=y > # CONFIG_PREEMPT is not set > # CONFIG_PREEMPT_DYNAMIC is not set > > dynamic (same config, just flip dynamic switch) > CONFIG_PREEMPT_BUILD=y > # CONFIG_PREEMPT_NONE is not set > CONFIG_PREEMPT_VOLUNTARY=y > # CONFIG_PREEMPT is not set > CONFIG_PREEMPT_COUNT=y > CONFIG_PREEMPTION=y > CONFIG_PREEMPT_DYNAMIC=y
Here is the full diff between the kernel configurations I used. The only change I made was setting CONFIG_PREEMPT_DYNAMIC=n, everything else was a consequence of that AFAICT, but please do let me know if you see anything that shouldn't be there.
--- config-6.5.0-0.preempt-dynamic-amd64 2023-10-11 15:30:02.000000000 +0200 +++ config-6.5.0-0.a.test-amd64 2023-10-11 14:30:02.000000000 +0200 @@ -125,13 +125,11 @@ CONFIG_BPF_LSM=y # end of BPF subsystem -CONFIG_PREEMPT_BUILD=y +CONFIG_PREEMPT_VOLUNTARY_BUILD=y # CONFIG_PREEMPT_NONE is not set CONFIG_PREEMPT_VOLUNTARY=y # CONFIG_PREEMPT is not set -CONFIG_PREEMPT_COUNT=y -CONFIG_PREEMPTION=y -CONFIG_PREEMPT_DYNAMIC=y +# CONFIG_PREEMPT_DYNAMIC is not set # CONFIG_SCHED_CORE is not set # @@ -156,11 +154,9 @@ # RCU Subsystem # CONFIG_TREE_RCU=y -CONFIG_PREEMPT_RCU=y # CONFIG_RCU_EXPERT is not set CONFIG_TREE_SRCU=y CONFIG_TASKS_RCU_GENERIC=y -CONFIG_TASKS_RCU=y CONFIG_TASKS_RUDE_RCU=y CONFIG_TASKS_TRACE_RCU=y CONFIG_RCU_STALL_COMMON=y @@ -1009,7 +1005,11 @@ CONFIG_PREEMPT_NOTIFIERS=y CONFIG_PADATA=y CONFIG_ASN1=y -CONFIG_UNINLINE_SPIN_UNLOCK=y +CONFIG_INLINE_SPIN_UNLOCK_IRQ=y +CONFIG_INLINE_READ_UNLOCK=y +CONFIG_INLINE_READ_UNLOCK_IRQ=y +CONFIG_INLINE_WRITE_UNLOCK=y +CONFIG_INLINE_WRITE_UNLOCK_IRQ=y CONFIG_ARCH_SUPPORTS_ATOMIC_RMW=y CONFIG_MUTEX_SPIN_ON_OWNER=y CONFIG_RWSEM_SPIN_ON_OWNER=y @@ -5395,7 +5395,6 @@ CONFIG_MEDIA_CEC_SUPPORT=y # CONFIG_CEC_CH7322 is not set # CONFIG_CEC_CROS_EC is not set -# CONFIG_CEC_GPIO is not set CONFIG_CEC_SECO=m # CONFIG_CEC_SECO_RC is not set CONFIG_USB_PULSE8_CEC=m @@ -10597,7 +10596,6 @@ # end of Scheduler Debugging # CONFIG_DEBUG_TIMEKEEPING is not set -CONFIG_DEBUG_PREEMPT=y # # Lock Debugging (spinlocks, mutexes, etc...) @@ -10696,7 +10694,6 @@ # CONFIG_FUNCTION_PROFILER is not set CONFIG_STACK_TRACER=y # CONFIG_IRQSOFF_TRACER is not set -# CONFIG_PREEMPT_TRACER is not set # CONFIG_SCHED_TRACER is not set # CONFIG_HWLAT_TRACER is not set # CONFIG_OSNOISE_TRACER is not set
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