Re: Trying add smt=off disabled cores to cpupool crash xen

[René Winther Højgaard <renewin@xxxxxxxxx>]

You are right about sched-gran=core being the issue.

I don't know if this is relevant, but my CPU shouldn't be able to use 
sched-gran=core it's asymmetric.

smt=on with sched-gran=core gives me a warning that it's falling back to 
sched-gran=cpu, I tested smt=off with sched-gran=cpu and it works.

This warning is missing with sched-gran=core and smt=off 

(XEN) ***************************************************
(XEN) Asymmetric cpu configuration.
(XEN) Falling back to sched-gran=cpu.
(XEN) ***************************************************


/rene


On Tuesday, December 5th, 2023 at 07:21, Juergen Gross <jgross@xxxxxxxx> wrote:


> On 04.12.23 18:40, René Winther Højgaard wrote:
> 

> > Hi Juergen,
> > 

> > Sorry for the late reply.
> > 

> > Here are the commands I execute, it is 'xl cpupool-cpu-add pcores 4-15' 
> > that crash the system.
> > 

> > xl cpupool-cpu-remove Pool-0 4-31
> > xl cpupool-create name=\"ecores\" sched=\"credit\"
> > xl cpupool-cpu-add ecores 16-31
> > 

> > xl cpupool-create name=\"pcores\" sched=\"credit\"
> > xl cpupool-cpu-add pcores 4-15
> > 

> > Here is the other information you asked for.
> > 

> > xl cpupool-list:
> > Name CPUs Sched Active Domain count
> > Pool-0 24 credit y 5
> > 

> > xl cpupool-list -c:
> > Name CPU list
> > Pool-0 0,2,4,6,8,10,12,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
> > 

> > xl info:
> > host : dom0
> > release : 6.1.62-1.qubes.fc37.x86_64
> > version : #1 SMP PREEMPT_DYNAMIC Tue Nov 14 06:16:38 GMT 2023
> > machine : x86_64
> > nr_cpus : 24
> > max_cpu_id : 31
> > nr_nodes : 1
> > cores_per_socket : 24
> > threads_per_core : 1
> > cpu_mhz : 2995.196
> > hw_caps : 
> > bfebfbff:77faf3ff:2c100800:00000121:0000000f:239c27eb:1840078c:00000100
> > virt_caps : pv hvm hvm_directio pv_directio hap iommu_hap_pt_share vmtrace 
> > gnttab-v1
> > total_memory : 65373
> > free_memory : 56505
> > sharing_freed_memory : 0
> > sharing_used_memory : 0
> > outstanding_claims : 0
> > free_cpus : 0
> > xen_major : 4
> > xen_minor : 17
> > xen_extra : .2
> > xen_version : 4.17.2
> > xen_caps : xen-3.0-x86_64 hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
> > 

> > xen_scheduler : credit
> > xen_pagesize : 4096
> > platform_params : virt_start=0xffff800000000000
> > xen_changeset :
> > 

> > xen_commandline : placeholder dom0_mem=min:2048M dom0_mem=max:4096M 
> > ucode=scan gnttab_max_frames=2048 gnttab_max_maptrack_frames=4096 smt=off 
> > dom0_max_vcpus=4 dom0_vcpus_pin sched-gran=core sched=credit no-real-mode 
> > edd=off
> 

> 

> Please drop the "sched-gran=core" from the Xen boot parameters. It doesn't 
> make
> any sense with smt=off and is adding additional complexity.
> 

> It shouldn't crash, but core scheduling is still "Experimental". I'll look 
> into
> the issue later.
> 

> 

> Juergen

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