lkml.org 
[lkml]   [2019]   [Feb]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 03/11] x86 topology: Add CPUID.1F multi-die/package support
From
Date
On 2019/2/24 18:04, Brice Goglin wrote:
> Le 19/02/2019 à 04:40, Len Brown a écrit :
>> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
>> index ccd1f2a8e557..4250a87f57db 100644
>> --- a/arch/x86/kernel/smpboot.c
>> +++ b/arch/x86/kernel/smpboot.c
>> @@ -393,6 +393,7 @@ static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
>> int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
>>
>> if (c->phys_proc_id == o->phys_proc_id &&
>> + c->cpu_die_id == o->cpu_die_id &&
>> per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) {
>> if (c->cpu_core_id == o->cpu_core_id)
>> return topology_sane(c, o, "smt");
>> @@ -404,6 +405,7 @@ static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
>> }
>>
>> } else if (c->phys_proc_id == o->phys_proc_id &&
>> + c->cpu_die_id == o->cpu_die_id &&
>> c->cpu_core_id == o->cpu_core_id) {
>> return topology_sane(c, o, "smt");
>> }
>> @@ -461,7 +463,7 @@ static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
>> */
>> static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
>> {
>> - if (c->phys_proc_id == o->phys_proc_id)
>> + if (c->cpu_die_id == o->cpu_die_id)
>> return true;
>> return false;
>> }
>
> Hello Len,
>
> I am testing your patches in a VM with CPUID.1f QEMU patches (author Like Xu is CC'ed),
> booted to get 2 packages with 1 NUMA node each and 2 dies each:
>
> -smp cpus=16,threads=2,cores=2,dies=2,sockets=2 -numa node,cpus=0-7,nodeid=0 -numa node,cpus=8-15,nodeid=1
>
> sysfs files expose wrong information:
> core_siblings contains threads of the local die AND of die with same number in other processors,
> eg cpu 0-3 and 8-11 instead of 0-3 only.
>
> The issue is that you seem to assume that die ids will always be unique across multiple packages.

I don't think the intel MCP topolohgy has this global uniqueness
assumption for die_id according to CPUID.1F SDM.

> Is this a valid assumption? If so, QEMU patches should be fixed.
> If not, I fixed the issue by changing match_die() to check both phys_proc_id and cpu_die_id:
>
> static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
> {
> if (c->phys_proc_id == o->phys_proc_id && c->cpu_die_id == o->cpu_die_id)
> return true;
> return false;
> }
>
> Thanks
> Brice
>
>
>

\
 
 \ /
  Last update: 2019-02-25 06:33    [W:0.059 / U:15.228 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site