Re: [PATCH v2 4/7] srcu: Add irqsave variants of the atomic SRCU readers

[Mathieu Desnoyers]

On 2026-11-11 15:04, Paul E. McKenney wrote:
> Aside from this in the console output:                                                                                                                        
>                                                                                                                                                               
> rcu_torture_nmi_cleanup: nmi_readers set but no reader ever ran in NMI, so NMI readers went untested (no PMU, or NMIs unavailable here).                      
>                                                                                                                                                               
> Looking into it.                                                                                                                                              
                                                                                                                                                                  
I expect this is a guest without a PMU.  The NMI source is a perf
counter, and kvm.sh starts x86 guests without one.  The readers in NMI
are then skipped, and this line says so.  The nmi_calls test prints the
same kind of line.
                                                                                                                                                                  
I ran with:
                                                                                                                                                                  
    --qemu-args "-cpu host,pmu=on"
                                                                                                                                                                  
With that, "NMI Reader Pipe:" and "NMI Reader Batch:" show up in the
statistics.  The cover letter mentions it, but the changelog of patch 5
does not.  I can add it there.
                                                                                                                                                                  
Thanks,
                                                                                                                                                                  
Mathieu


--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com