[Qemu-devel] [RFC 0/4] numa, spapr: add thread-id in the possible_cpus list

[Qemu-devel] [RFC 0/4] numa, spapr: add thread-id in the possible_cpus list

[Laurent Vivier]

There are inconsistencies between the command line using
"-numa node,cpus=XX" and what is checked internally:
the XX is supposed to be a CPU number, but for SPAPR
it's taken as a core number, ignoring the threads.
(See the description message of PATCH 1 for more details)

This series fixes this problem by introducing the threads
in the possible_cpus list instead of only the cores.
To avoid inconsistent topology, it doesn't allow anymore to
have an incomplete CPU NUMA config on the command line
(there was already a message announcing it will be absoleted
for 2 years).

Laurent Vivier (4):
  numa,spapr: add thread-id in the possible_cpus list
  numa: exit on incomplete CPU mapping
  numa: move cpu_slot_to_string() upper in the function
  numa: check threads of the same core are on the same node

 hw/core/machine.c | 115 ++++++++++++++++++++++++++--------------------
 hw/ppc/spapr.c    |  33 ++++++-------
 tests/numa-test.c |  24 +---------
 3 files changed, 81 insertions(+), 91 deletions(-)

-- 
2.20.1

[Qemu-devel] [RFC 1/4] numa, spapr: add thread-id in the possible_cpus list

[Laurent Vivier]

spapr_possible_cpu_arch_ids() counts only cores, and so
the number of available CPUs is the number of vCPU divided
by smp_threads.

... -smp 4,maxcpus=8,cores=2,threads=2,sockets=2 -numa node,cpus=0,cpus=1 \
                                                 -numa node,cpus=3,cpus=4 \
                                                 -numa node -numa node

This generates (info hotpluggable-cpus)

  node-id: 0 core-id: 0 thread-id: 0 [thread-id: 1]
  node-id: 0 core-id: 6 thread-id: 0 [thread-id: 1]
  node-id: 1 core-id: 2 thread-id: 0 [thread-id: 1]
  node-id: 1 core-id: 4 thread-id: 0 [thread-id: 1]

And this command line generates the following error:

  CPU(s) not present in any NUMA nodes: CPU 3 [core-id: 6]

That is wrong because CPU 3 [core-id: 6] is assigned to node-id 0
Moreover "cpus=4" is not valid, because it means core-id 8 but
maxcpus is 8.

With this patch we have now:

  node-id: 0 core-id: 0 thread-id: 0
  node-id: 0 core-id: 0 thread-id: 1
  node-id: 0 core-id: 1 thread-id: 0
  node-id: 1 core-id: 1 thread-id: 1
  node-id: 0 core-id: 2 thread-id: 1
  node-id: 1 core-id: 2 thread-id: 0
  node-id: 0 core-id: 3 thread-id: 1
  node-id: 0 core-id: 3 thread-id: 0

CPUs 0 (core-id: 0 thread-id: 0) and 1 (core-id: 0 thread-id: 1) are
correctly assigned to node-id 0, CPUs 3 (core-id: 1 thread-id: 1) and
 4 (core-id: 2 thread-id: 0) are correctly assigned to node-id 1.
All other CPUs are assigned to node-id 0 by default.

And the error message is also correct:

  CPU(s) not present in any NUMA nodes: CPU 2 [core-id: 1, thread-id: 0], \
                                        CPU 5 [core-id: 2, thread-id: 1], \
                                        CPU 6 [core-id: 3, thread-id: 0], \
                                        CPU 7 [core-id: 3, thread-id: 1]

Fixes: ec78f8114bc4 ("numa: use possible_cpus for not mapped CPUs check")
Cc: imammedo@redhat.com

Before commit ec78f8114bc4, output was correct:

  CPU(s) not present in any NUMA nodes: 2 5 6 7

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 hw/ppc/spapr.c | 33 +++++++++++++--------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 332cba89d425..7196ba09da34 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2404,15 +2404,13 @@ static void spapr_validate_node_memory(MachineState *machine, Error **errp)
 /* find cpu slot in machine->possible_cpus by core_id */
 static CPUArchId *spapr_find_cpu_slot(MachineState *ms, uint32_t id, int *idx)
 {
-    int index = id / smp_threads;
-
-    if (index >= ms->possible_cpus->len) {
+    if (id >= ms->possible_cpus->len) {
         return NULL;
     }
     if (idx) {
-        *idx = index;
+        *idx = id;
     }
-    return &ms->possible_cpus->cpus[index];
+    return &ms->possible_cpus->cpus[id];
 }
 
 static void spapr_set_vsmt_mode(sPAPRMachineState *spapr, Error **errp)
@@ -2514,7 +2512,7 @@ static void spapr_init_cpus(sPAPRMachineState *spapr)
             error_report("This machine version does not support CPU hotplug");
             exit(1);
         }
-        boot_cores_nr = possible_cpus->len;
+        boot_cores_nr = possible_cpus->len / smp_threads;
     }
 
     if (smc->pre_2_10_has_unused_icps) {
@@ -2528,7 +2526,7 @@ static void spapr_init_cpus(sPAPRMachineState *spapr)
         }
     }
 
-    for (i = 0; i < possible_cpus->len; i++) {
+    for (i = 0; i < possible_cpus->len / smp_threads; i++) {
         int core_id = i * smp_threads;
 
         if (mc->has_hotpluggable_cpus) {
@@ -3795,21 +3793,16 @@ spapr_cpu_index_to_props(MachineState *machine, unsigned cpu_index)
 
 static int64_t spapr_get_default_cpu_node_id(const MachineState *ms, int idx)
 {
-    return idx / smp_cores % nb_numa_nodes;
+    return idx / (smp_cores * smp_threads) % nb_numa_nodes;
 }
 
 static const CPUArchIdList *spapr_possible_cpu_arch_ids(MachineState *machine)
 {
     int i;
     const char *core_type;
-    int spapr_max_cores = max_cpus / smp_threads;
-    MachineClass *mc = MACHINE_GET_CLASS(machine);
 
-    if (!mc->has_hotpluggable_cpus) {
-        spapr_max_cores = QEMU_ALIGN_UP(smp_cpus, smp_threads) / smp_threads;
-    }
     if (machine->possible_cpus) {
-        assert(machine->possible_cpus->len == spapr_max_cores);
+        assert(machine->possible_cpus->len == max_cpus);
         return machine->possible_cpus;
     }
 
@@ -3820,16 +3813,16 @@ static const CPUArchIdList *spapr_possible_cpu_arch_ids(MachineState *machine)
     }
 
     machine->possible_cpus = g_malloc0(sizeof(CPUArchIdList) +
-                             sizeof(CPUArchId) * spapr_max_cores);
-    machine->possible_cpus->len = spapr_max_cores;
+                             sizeof(CPUArchId) * max_cpus);
+    machine->possible_cpus->len = max_cpus;
     for (i = 0; i < machine->possible_cpus->len; i++) {
-        int core_id = i * smp_threads;
-
         machine->possible_cpus->cpus[i].type = core_type;
         machine->possible_cpus->cpus[i].vcpus_count = smp_threads;
-        machine->possible_cpus->cpus[i].arch_id = core_id;
+        machine->possible_cpus->cpus[i].arch_id = i;
         machine->possible_cpus->cpus[i].props.has_core_id = true;
-        machine->possible_cpus->cpus[i].props.core_id = core_id;
+        machine->possible_cpus->cpus[i].props.core_id = i / smp_threads;
+        machine->possible_cpus->cpus[i].props.has_thread_id = true;
+        machine->possible_cpus->cpus[i].props.thread_id = i % smp_threads;
     }
     return machine->possible_cpus;
 }
-- 
2.20.1

Re: [Qemu-devel] [RFC 1/4] numa, spapr: add thread-id in the possible_cpus list

[David Gibson]

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On Tue, Feb 12, 2019 at 10:48:24PM +0100, Laurent Vivier wrote:
> spapr_possible_cpu_arch_ids() counts only cores, and so
> the number of available CPUs is the number of vCPU divided
> by smp_threads.
> 
> ... -smp 4,maxcpus=8,cores=2,threads=2,sockets=2 -numa node,cpus=0,cpus=1 \
>                                                  -numa node,cpus=3,cpus=4 \
>                                                  -numa node -numa node
> 
> This generates (info hotpluggable-cpus)
> 
>   node-id: 0 core-id: 0 thread-id: 0 [thread-id: 1]
>   node-id: 0 core-id: 6 thread-id: 0 [thread-id: 1]
>   node-id: 1 core-id: 2 thread-id: 0 [thread-id: 1]
>   node-id: 1 core-id: 4 thread-id: 0 [thread-id: 1]
> 
> And this command line generates the following error:
> 
>   CPU(s) not present in any NUMA nodes: CPU 3 [core-id: 6]
> 
> That is wrong because CPU 3 [core-id: 6] is assigned to node-id 0
> Moreover "cpus=4" is not valid, because it means core-id 8 but
> maxcpus is 8.
> 
> With this patch we have now:
> 
>   node-id: 0 core-id: 0 thread-id: 0
>   node-id: 0 core-id: 0 thread-id: 1
>   node-id: 0 core-id: 1 thread-id: 0
>   node-id: 1 core-id: 1 thread-id: 1
>   node-id: 0 core-id: 2 thread-id: 1
>   node-id: 1 core-id: 2 thread-id: 0
>   node-id: 0 core-id: 3 thread-id: 1
>   node-id: 0 core-id: 3 thread-id: 0

I'm afraid this is not the right solution.  The point of the
hotpluggable cpus table is that it has exactly one entry for each
hotpluggable unit.  For PAPR that's a core, not a thread.

So, the problem is with how the NUMA configuration code is
interpreting possible-cpus, not how the machine is building the table.

> CPUs 0 (core-id: 0 thread-id: 0) and 1 (core-id: 0 thread-id: 1) are
> correctly assigned to node-id 0, CPUs 3 (core-id: 1 thread-id: 1) and
>  4 (core-id: 2 thread-id: 0) are correctly assigned to node-id 1.
> All other CPUs are assigned to node-id 0 by default.
> 
> And the error message is also correct:
> 
>   CPU(s) not present in any NUMA nodes: CPU 2 [core-id: 1, thread-id: 0], \
>                                         CPU 5 [core-id: 2, thread-id: 1], \
>                                         CPU 6 [core-id: 3, thread-id: 0], \
>                                         CPU 7 [core-id: 3, thread-id: 1]
> 
> Fixes: ec78f8114bc4 ("numa: use possible_cpus for not mapped CPUs check")
> Cc: imammedo@redhat.com
> 
> Before commit ec78f8114bc4, output was correct:
> 
>   CPU(s) not present in any NUMA nodes: 2 5 6 7
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  hw/ppc/spapr.c | 33 +++++++++++++--------------------
>  1 file changed, 13 insertions(+), 20 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 332cba89d425..7196ba09da34 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2404,15 +2404,13 @@ static void spapr_validate_node_memory(MachineState *machine, Error **errp)
>  /* find cpu slot in machine->possible_cpus by core_id */
>  static CPUArchId *spapr_find_cpu_slot(MachineState *ms, uint32_t id, int *idx)
>  {
> -    int index = id / smp_threads;
> -
> -    if (index >= ms->possible_cpus->len) {
> +    if (id >= ms->possible_cpus->len) {
>          return NULL;
>      }
>      if (idx) {
> -        *idx = index;
> +        *idx = id;
>      }
> -    return &ms->possible_cpus->cpus[index];
> +    return &ms->possible_cpus->cpus[id];
>  }
>  
>  static void spapr_set_vsmt_mode(sPAPRMachineState *spapr, Error **errp)
> @@ -2514,7 +2512,7 @@ static void spapr_init_cpus(sPAPRMachineState *spapr)
>              error_report("This machine version does not support CPU hotplug");
>              exit(1);
>          }
> -        boot_cores_nr = possible_cpus->len;
> +        boot_cores_nr = possible_cpus->len / smp_threads;
>      }
>  
>      if (smc->pre_2_10_has_unused_icps) {
> @@ -2528,7 +2526,7 @@ static void spapr_init_cpus(sPAPRMachineState *spapr)
>          }
>      }
>  
> -    for (i = 0; i < possible_cpus->len; i++) {
> +    for (i = 0; i < possible_cpus->len / smp_threads; i++) {
>          int core_id = i * smp_threads;
>  
>          if (mc->has_hotpluggable_cpus) {
> @@ -3795,21 +3793,16 @@ spapr_cpu_index_to_props(MachineState *machine, unsigned cpu_index)
>  
>  static int64_t spapr_get_default_cpu_node_id(const MachineState *ms, int idx)
>  {
> -    return idx / smp_cores % nb_numa_nodes;
> +    return idx / (smp_cores * smp_threads) % nb_numa_nodes;
>  }
>  
>  static const CPUArchIdList *spapr_possible_cpu_arch_ids(MachineState *machine)
>  {
>      int i;
>      const char *core_type;
> -    int spapr_max_cores = max_cpus / smp_threads;
> -    MachineClass *mc = MACHINE_GET_CLASS(machine);
>  
> -    if (!mc->has_hotpluggable_cpus) {
> -        spapr_max_cores = QEMU_ALIGN_UP(smp_cpus, smp_threads) / smp_threads;
> -    }
>      if (machine->possible_cpus) {
> -        assert(machine->possible_cpus->len == spapr_max_cores);
> +        assert(machine->possible_cpus->len == max_cpus);
>          return machine->possible_cpus;
>      }
>  
> @@ -3820,16 +3813,16 @@ static const CPUArchIdList *spapr_possible_cpu_arch_ids(MachineState *machine)
>      }
>  
>      machine->possible_cpus = g_malloc0(sizeof(CPUArchIdList) +
> -                             sizeof(CPUArchId) * spapr_max_cores);
> -    machine->possible_cpus->len = spapr_max_cores;
> +                             sizeof(CPUArchId) * max_cpus);
> +    machine->possible_cpus->len = max_cpus;
>      for (i = 0; i < machine->possible_cpus->len; i++) {
> -        int core_id = i * smp_threads;
> -
>          machine->possible_cpus->cpus[i].type = core_type;
>          machine->possible_cpus->cpus[i].vcpus_count = smp_threads;
> -        machine->possible_cpus->cpus[i].arch_id = core_id;
> +        machine->possible_cpus->cpus[i].arch_id = i;
>          machine->possible_cpus->cpus[i].props.has_core_id = true;
> -        machine->possible_cpus->cpus[i].props.core_id = core_id;
> +        machine->possible_cpus->cpus[i].props.core_id = i / smp_threads;
> +        machine->possible_cpus->cpus[i].props.has_thread_id = true;
> +        machine->possible_cpus->cpus[i].props.thread_id = i % smp_threads;
>      }
>      return machine->possible_cpus;
>  }

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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Re: [Qemu-devel] [RFC 1/4] numa, spapr: add thread-id in the possible_cpus list

[Igor Mammedov]

On Wed, 13 Feb 2019 12:25:45 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Tue, Feb 12, 2019 at 10:48:24PM +0100, Laurent Vivier wrote:
> > spapr_possible_cpu_arch_ids() counts only cores, and so
> > the number of available CPUs is the number of vCPU divided
> > by smp_threads.
> > 
> > ... -smp 4,maxcpus=8,cores=2,threads=2,sockets=2 -numa node,cpus=0,cpus=1 \
> >                                                  -numa node,cpus=3,cpus=4 \
> >                                                  -numa node -numa node
> > 
> > This generates (info hotpluggable-cpus)
> > 
> >   node-id: 0 core-id: 0 thread-id: 0 [thread-id: 1]
> >   node-id: 0 core-id: 6 thread-id: 0 [thread-id: 1]
> >   node-id: 1 core-id: 2 thread-id: 0 [thread-id: 1]
> >   node-id: 1 core-id: 4 thread-id: 0 [thread-id: 1]
> > 
> > And this command line generates the following error:
> > 
> >   CPU(s) not present in any NUMA nodes: CPU 3 [core-id: 6]
> > 
> > That is wrong because CPU 3 [core-id: 6] is assigned to node-id 0
> > Moreover "cpus=4" is not valid, because it means core-id 8 but
> > maxcpus is 8.
> > 
> > With this patch we have now:
> > 
> >   node-id: 0 core-id: 0 thread-id: 0
> >   node-id: 0 core-id: 0 thread-id: 1
> >   node-id: 0 core-id: 1 thread-id: 0
> >   node-id: 1 core-id: 1 thread-id: 1
> >   node-id: 0 core-id: 2 thread-id: 1
> >   node-id: 1 core-id: 2 thread-id: 0
> >   node-id: 0 core-id: 3 thread-id: 1
> >   node-id: 0 core-id: 3 thread-id: 0  
> 
> I'm afraid this is not the right solution.  The point of the
> hotpluggable cpus table is that it has exactly one entry for each
> hotpluggable unit.  For PAPR that's a core, not a thread.
> 
> So, the problem is with how the NUMA configuration code is
> interpreting possible-cpus, not how the machine is building the table.

I'd suggest to deprecate/remove 'cpus' suboption in -numa.
One should use '-numa cpu' instead, which is written with
possible_cpus in mind.

> 
> > CPUs 0 (core-id: 0 thread-id: 0) and 1 (core-id: 0 thread-id: 1) are
> > correctly assigned to node-id 0, CPUs 3 (core-id: 1 thread-id: 1) and
> >  4 (core-id: 2 thread-id: 0) are correctly assigned to node-id 1.
> > All other CPUs are assigned to node-id 0 by default.
> > 
> > And the error message is also correct:
> > 
> >   CPU(s) not present in any NUMA nodes: CPU 2 [core-id: 1, thread-id: 0], \
> >                                         CPU 5 [core-id: 2, thread-id: 1], \
> >                                         CPU 6 [core-id: 3, thread-id: 0], \
> >                                         CPU 7 [core-id: 3, thread-id: 1]
> > 
> > Fixes: ec78f8114bc4 ("numa: use possible_cpus for not mapped CPUs check")
> > Cc: imammedo@redhat.com
> > 
> > Before commit ec78f8114bc4, output was correct:
> > 
> >   CPU(s) not present in any NUMA nodes: 2 5 6 7
> > 
> > Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> > ---
> >  hw/ppc/spapr.c | 33 +++++++++++++--------------------
> >  1 file changed, 13 insertions(+), 20 deletions(-)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 332cba89d425..7196ba09da34 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -2404,15 +2404,13 @@ static void spapr_validate_node_memory(MachineState *machine, Error **errp)
> >  /* find cpu slot in machine->possible_cpus by core_id */
> >  static CPUArchId *spapr_find_cpu_slot(MachineState *ms, uint32_t id, int *idx)
> >  {
> > -    int index = id / smp_threads;
> > -
> > -    if (index >= ms->possible_cpus->len) {
> > +    if (id >= ms->possible_cpus->len) {
> >          return NULL;
> >      }
> >      if (idx) {
> > -        *idx = index;
> > +        *idx = id;
> >      }
> > -    return &ms->possible_cpus->cpus[index];
> > +    return &ms->possible_cpus->cpus[id];
> >  }
> >  
> >  static void spapr_set_vsmt_mode(sPAPRMachineState *spapr, Error **errp)
> > @@ -2514,7 +2512,7 @@ static void spapr_init_cpus(sPAPRMachineState *spapr)
> >              error_report("This machine version does not support CPU hotplug");
> >              exit(1);
> >          }
> > -        boot_cores_nr = possible_cpus->len;
> > +        boot_cores_nr = possible_cpus->len / smp_threads;
> >      }
> >  
> >      if (smc->pre_2_10_has_unused_icps) {
> > @@ -2528,7 +2526,7 @@ static void spapr_init_cpus(sPAPRMachineState *spapr)
> >          }
> >      }
> >  
> > -    for (i = 0; i < possible_cpus->len; i++) {
> > +    for (i = 0; i < possible_cpus->len / smp_threads; i++) {
> >          int core_id = i * smp_threads;
> >  
> >          if (mc->has_hotpluggable_cpus) {
> > @@ -3795,21 +3793,16 @@ spapr_cpu_index_to_props(MachineState *machine, unsigned cpu_index)
> >  
> >  static int64_t spapr_get_default_cpu_node_id(const MachineState *ms, int idx)
> >  {
> > -    return idx / smp_cores % nb_numa_nodes;
> > +    return idx / (smp_cores * smp_threads) % nb_numa_nodes;
> >  }
> >  
> >  static const CPUArchIdList *spapr_possible_cpu_arch_ids(MachineState *machine)
> >  {
> >      int i;
> >      const char *core_type;
> > -    int spapr_max_cores = max_cpus / smp_threads;
> > -    MachineClass *mc = MACHINE_GET_CLASS(machine);
> >  
> > -    if (!mc->has_hotpluggable_cpus) {
> > -        spapr_max_cores = QEMU_ALIGN_UP(smp_cpus, smp_threads) / smp_threads;
> > -    }
> >      if (machine->possible_cpus) {
> > -        assert(machine->possible_cpus->len == spapr_max_cores);
> > +        assert(machine->possible_cpus->len == max_cpus);
> >          return machine->possible_cpus;
> >      }
> >  
> > @@ -3820,16 +3813,16 @@ static const CPUArchIdList *spapr_possible_cpu_arch_ids(MachineState *machine)
> >      }
> >  
> >      machine->possible_cpus = g_malloc0(sizeof(CPUArchIdList) +
> > -                             sizeof(CPUArchId) * spapr_max_cores);
> > -    machine->possible_cpus->len = spapr_max_cores;
> > +                             sizeof(CPUArchId) * max_cpus);
> > +    machine->possible_cpus->len = max_cpus;
> >      for (i = 0; i < machine->possible_cpus->len; i++) {
> > -        int core_id = i * smp_threads;
> > -
> >          machine->possible_cpus->cpus[i].type = core_type;
> >          machine->possible_cpus->cpus[i].vcpus_count = smp_threads;
> > -        machine->possible_cpus->cpus[i].arch_id = core_id;
> > +        machine->possible_cpus->cpus[i].arch_id = i;
> >          machine->possible_cpus->cpus[i].props.has_core_id = true;
> > -        machine->possible_cpus->cpus[i].props.core_id = core_id;
> > +        machine->possible_cpus->cpus[i].props.core_id = i / smp_threads;
> > +        machine->possible_cpus->cpus[i].props.has_thread_id = true;
> > +        machine->possible_cpus->cpus[i].props.thread_id = i % smp_threads;
> >      }
> >      return machine->possible_cpus;
> >  }  
> 

Re: [Qemu-devel] [RFC 1/4] numa, spapr: add thread-id in the possible_cpus list

[Laurent Vivier]

On 13/02/2019 09:42, Igor Mammedov wrote:
> On Wed, 13 Feb 2019 12:25:45 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
>> On Tue, Feb 12, 2019 at 10:48:24PM +0100, Laurent Vivier wrote:
>>> spapr_possible_cpu_arch_ids() counts only cores, and so
>>> the number of available CPUs is the number of vCPU divided
>>> by smp_threads.
>>>
>>> ... -smp 4,maxcpus=8,cores=2,threads=2,sockets=2 -numa node,cpus=0,cpus=1 \
>>>                                                   -numa node,cpus=3,cpus=4 \
>>>                                                   -numa node -numa node
>>>
>>> This generates (info hotpluggable-cpus)
>>>
>>>    node-id: 0 core-id: 0 thread-id: 0 [thread-id: 1]
>>>    node-id: 0 core-id: 6 thread-id: 0 [thread-id: 1]
>>>    node-id: 1 core-id: 2 thread-id: 0 [thread-id: 1]
>>>    node-id: 1 core-id: 4 thread-id: 0 [thread-id: 1]
>>>
>>> And this command line generates the following error:
>>>
>>>    CPU(s) not present in any NUMA nodes: CPU 3 [core-id: 6]
>>>
>>> That is wrong because CPU 3 [core-id: 6] is assigned to node-id 0
>>> Moreover "cpus=4" is not valid, because it means core-id 8 but
>>> maxcpus is 8.
>>>
>>> With this patch we have now:
>>>
>>>    node-id: 0 core-id: 0 thread-id: 0
>>>    node-id: 0 core-id: 0 thread-id: 1
>>>    node-id: 0 core-id: 1 thread-id: 0
>>>    node-id: 1 core-id: 1 thread-id: 1
>>>    node-id: 0 core-id: 2 thread-id: 1
>>>    node-id: 1 core-id: 2 thread-id: 0
>>>    node-id: 0 core-id: 3 thread-id: 1
>>>    node-id: 0 core-id: 3 thread-id: 0
>>
>> I'm afraid this is not the right solution.  The point of the
>> hotpluggable cpus table is that it has exactly one entry for each
>> hotpluggable unit.  For PAPR that's a core, not a thread.
>>
>> So, the problem is with how the NUMA configuration code is
>> interpreting possible-cpus, not how the machine is building the table.
> 
> I'd suggest to deprecate/remove 'cpus' suboption in -numa.
> One should use '-numa cpu' instead, which is written with
> possible_cpus in mind.

I agree.

Should I keep the patch to remove the incomplete CPU mapping support?

Thanks,
Laurent

Re: [Qemu-devel] [RFC 1/4] numa, spapr: add thread-id in the possible_cpus list

[Igor Mammedov]

On Wed, 13 Feb 2019 10:08:24 +0100
Laurent Vivier <lvivier@redhat.com> wrote:

> On 13/02/2019 09:42, Igor Mammedov wrote:
> > On Wed, 13 Feb 2019 12:25:45 +1100
> > David Gibson <david@gibson.dropbear.id.au> wrote:
> >   
> >> On Tue, Feb 12, 2019 at 10:48:24PM +0100, Laurent Vivier wrote:  
> >>> spapr_possible_cpu_arch_ids() counts only cores, and so
> >>> the number of available CPUs is the number of vCPU divided
> >>> by smp_threads.
> >>>
> >>> ... -smp 4,maxcpus=8,cores=2,threads=2,sockets=2 -numa node,cpus=0,cpus=1 \
> >>>                                                   -numa node,cpus=3,cpus=4 \
> >>>                                                   -numa node -numa node
> >>>
> >>> This generates (info hotpluggable-cpus)
> >>>
> >>>    node-id: 0 core-id: 0 thread-id: 0 [thread-id: 1]
> >>>    node-id: 0 core-id: 6 thread-id: 0 [thread-id: 1]
> >>>    node-id: 1 core-id: 2 thread-id: 0 [thread-id: 1]
> >>>    node-id: 1 core-id: 4 thread-id: 0 [thread-id: 1]
> >>>
> >>> And this command line generates the following error:
> >>>
> >>>    CPU(s) not present in any NUMA nodes: CPU 3 [core-id: 6]
> >>>
> >>> That is wrong because CPU 3 [core-id: 6] is assigned to node-id 0
> >>> Moreover "cpus=4" is not valid, because it means core-id 8 but
> >>> maxcpus is 8.
> >>>
> >>> With this patch we have now:
> >>>
> >>>    node-id: 0 core-id: 0 thread-id: 0
> >>>    node-id: 0 core-id: 0 thread-id: 1
> >>>    node-id: 0 core-id: 1 thread-id: 0
> >>>    node-id: 1 core-id: 1 thread-id: 1
> >>>    node-id: 0 core-id: 2 thread-id: 1
> >>>    node-id: 1 core-id: 2 thread-id: 0
> >>>    node-id: 0 core-id: 3 thread-id: 1
> >>>    node-id: 0 core-id: 3 thread-id: 0  
> >>
> >> I'm afraid this is not the right solution.  The point of the
> >> hotpluggable cpus table is that it has exactly one entry for each
> >> hotpluggable unit.  For PAPR that's a core, not a thread.
> >>
> >> So, the problem is with how the NUMA configuration code is
> >> interpreting possible-cpus, not how the machine is building the table.  
> > 
> > I'd suggest to deprecate/remove 'cpus' suboption in -numa.
> > One should use '-numa cpu' instead, which is written with
> > possible_cpus in mind.  
> 
> I agree.
> 
> Should I keep the patch to remove the incomplete CPU mapping support?
Considering code path didn't go through deprecation process (we didn't have it back then), lets keep it for now and deprecate option properly first.
Once deprecation period ends we well remove all related code at once.

Maybe amend affected/add error messages that it's been deprecated
and will be removed soon and point out to replacement option.



> Thanks,
> Laurent

[Qemu-devel] [RFC 2/4] numa: exit on incomplete CPU mapping

[Laurent Vivier]

Change the existing message to an error and exit.

This message was a warning and comes with the information
it will be removed in the future since May 10 2017
(ec78f8114bc4 "numa: use possible_cpus for not mapped CPUs check").

Update tests/numa-test to remove the incomplete CPU mapping test.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 hw/core/machine.c | 46 +++++++++++++++++++++-------------------------
 tests/numa-test.c | 20 --------------------
 2 files changed, 21 insertions(+), 45 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 077fbd182adf..7c74b318f635 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -873,51 +873,47 @@ static char *cpu_slot_to_string(const CPUArchId *cpu)
 static void machine_numa_finish_cpu_init(MachineState *machine)
 {
     int i;
-    bool default_mapping;
+    bool default_mapping = true;
     GString *s = g_string_new(NULL);
     MachineClass *mc = MACHINE_GET_CLASS(machine);
     const CPUArchIdList *possible_cpus = mc->possible_cpu_arch_ids(machine);
+    const CPUArchId *cpu_slot;
 
     assert(nb_numa_nodes);
     for (i = 0; i < possible_cpus->len; i++) {
-        if (possible_cpus->cpus[i].props.has_node_id) {
-            break;
+        cpu_slot = &possible_cpus->cpus[i];
+
+        if (cpu_slot->props.has_node_id) {
+            default_mapping = false;
+        } else {
+            /* record slots with not set mapping, */
+            char *cpu_str = cpu_slot_to_string(cpu_slot);
+            g_string_append_printf(s, "%sCPU %d [%s]",
+                                   s->len ? ", " : "", i, cpu_str);
+            g_free(cpu_str);
         }
     }
-    default_mapping = (i == possible_cpus->len);
+    if (!default_mapping && s->len && !qtest_enabled()) {
+        error_report("CPU(s) not present in any NUMA nodes: %s", s->str);
+        error_report("All CPU(s) up to maxcpus must be described "
+                    "in NUMA config");
+        g_string_free(s, true);
+        exit(1);
+    }
+    g_string_free(s, true);
 
     for (i = 0; i < possible_cpus->len; i++) {
-        const CPUArchId *cpu_slot = &possible_cpus->cpus[i];
+        cpu_slot = &possible_cpus->cpus[i];
 
         if (!cpu_slot->props.has_node_id) {
             /* fetch default mapping from board and enable it */
             CpuInstanceProperties props = cpu_slot->props;
 
             props.node_id = mc->get_default_cpu_node_id(machine, i);
-            if (!default_mapping) {
-                /* record slots with not set mapping,
-                 * TODO: make it hard error in future */
-                char *cpu_str = cpu_slot_to_string(cpu_slot);
-                g_string_append_printf(s, "%sCPU %d [%s]",
-                                       s->len ? ", " : "", i, cpu_str);
-                g_free(cpu_str);
-
-                /* non mapped cpus used to fallback to node 0 */
-                props.node_id = 0;
-            }
-
             props.has_node_id = true;
             machine_set_cpu_numa_node(machine, &props, &error_fatal);
         }
     }
-    if (s->len && !qtest_enabled()) {
-        warn_report("CPU(s) not present in any NUMA nodes: %s",
-                    s->str);
-        warn_report("All CPU(s) up to maxcpus should be described "
-                    "in NUMA config, ability to start up with partial NUMA "
-                    "mappings is obsoleted and will be removed in future");
-    }
-    g_string_free(s, true);
 }
 
 void machine_run_board_init(MachineState *machine)
diff --git a/tests/numa-test.c b/tests/numa-test.c
index 9824fdd5875e..5280573fc992 100644
--- a/tests/numa-test.c
+++ b/tests/numa-test.c
@@ -55,25 +55,6 @@ static void test_mon_default(const void *data)
     g_free(cli);
 }
 
-static void test_mon_partial(const void *data)
-{
-    char *s;
-    char *cli;
-
-    cli = make_cli(data, "-smp 8 "
-                   "-numa node,nodeid=0,cpus=0-1 "
-                   "-numa node,nodeid=1,cpus=4-5 ");
-    qtest_start(cli);
-
-    s = hmp("info numa");
-    g_assert(strstr(s, "node 0 cpus: 0 1 2 3 6 7"));
-    g_assert(strstr(s, "node 1 cpus: 4 5"));
-    g_free(s);
-
-    qtest_end();
-    g_free(cli);
-}
-
 static QList *get_cpus(QDict **resp)
 {
     *resp = qmp("{ 'execute': 'query-cpus' }");
@@ -333,7 +314,6 @@ int main(int argc, char **argv)
 
     qtest_add_data_func("/numa/mon/default", args, test_mon_default);
     qtest_add_data_func("/numa/mon/cpus/explicit", args, test_mon_explicit);
-    qtest_add_data_func("/numa/mon/cpus/partial", args, test_mon_partial);
     qtest_add_data_func("/numa/qmp/cpus/query-cpus", args, test_query_cpus);
 
     if (!strcmp(arch, "i386") || !strcmp(arch, "x86_64")) {
-- 
2.20.1

[Qemu-devel] [RFC 3/4] numa: move cpu_slot_to_string() upper in the function

[Laurent Vivier]

This will allow to use it in more functions in the future.

As we change the prototype to take directly CpuInstanceProperties
instead of CPUArchId, rename the function to cpu_props_to_string().

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 hw/core/machine.c | 44 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 7c74b318f635..a2c29692b55e 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -550,6 +550,27 @@ HotpluggableCPUList *machine_query_hotpluggable_cpus(MachineState *machine)
     return head;
 }
 
+static char *cpu_props_to_string(const CpuInstanceProperties *props)
+{
+    GString *s = g_string_new(NULL);
+    if (props->has_socket_id) {
+        g_string_append_printf(s, "socket-id: %"PRId64, props->socket_id);
+    }
+    if (props->has_core_id) {
+        if (s->len) {
+            g_string_append_printf(s, ", ");
+        }
+        g_string_append_printf(s, "core-id: %"PRId64, props->core_id);
+    }
+    if (props->has_thread_id) {
+        if (s->len) {
+            g_string_append_printf(s, ", ");
+        }
+        g_string_append_printf(s, "thread-id: %"PRId64, props->thread_id);
+    }
+    return g_string_free(s, false);
+}
+
 /**
  * machine_set_cpu_numa_node:
  * @machine: machine object to modify
@@ -849,27 +870,6 @@ bool machine_mem_merge(MachineState *machine)
     return machine->mem_merge;
 }
 
-static char *cpu_slot_to_string(const CPUArchId *cpu)
-{
-    GString *s = g_string_new(NULL);
-    if (cpu->props.has_socket_id) {
-        g_string_append_printf(s, "socket-id: %"PRId64, cpu->props.socket_id);
-    }
-    if (cpu->props.has_core_id) {
-        if (s->len) {
-            g_string_append_printf(s, ", ");
-        }
-        g_string_append_printf(s, "core-id: %"PRId64, cpu->props.core_id);
-    }
-    if (cpu->props.has_thread_id) {
-        if (s->len) {
-            g_string_append_printf(s, ", ");
-        }
-        g_string_append_printf(s, "thread-id: %"PRId64, cpu->props.thread_id);
-    }
-    return g_string_free(s, false);
-}
-
 static void machine_numa_finish_cpu_init(MachineState *machine)
 {
     int i;
@@ -887,7 +887,7 @@ static void machine_numa_finish_cpu_init(MachineState *machine)
             default_mapping = false;
         } else {
             /* record slots with not set mapping, */
-            char *cpu_str = cpu_slot_to_string(cpu_slot);
+            char *cpu_str = cpu_props_to_string(&cpu_slot->props);
             g_string_append_printf(s, "%sCPU %d [%s]",
                                    s->len ? ", " : "", i, cpu_str);
             g_free(cpu_str);
-- 
2.20.1

[Qemu-devel] [RFC 4/4] numa: check threads of the same core are on the same node

[Laurent Vivier]

A core cannot be split between two nodes.
To check if a thread of the same core has already been assigned to a node,
this patch reverses the numa topology checking order and exits if the
topology is not valid.

Update test/numa-test accordingly.

Fixes: 722387e78daf ("spapr: get numa node mapping from possible_cpus instead of numa_get_node_for_cpu()")
Cc: imammedo@redhat.com
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 hw/core/machine.c | 27 ++++++++++++++++++++++++---
 tests/numa-test.c |  4 ++--
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index a2c29692b55e..c0a556b0dce7 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -602,6 +602,7 @@ void machine_set_cpu_numa_node(MachineState *machine,
     MachineClass *mc = MACHINE_GET_CLASS(machine);
     bool match = false;
     int i;
+    const CpuInstanceProperties *previous_props = NULL;
 
     if (!mc->possible_cpu_arch_ids) {
         error_setg(errp, "mapping of CPUs to NUMA node is not supported");
@@ -634,18 +635,38 @@ void machine_set_cpu_numa_node(MachineState *machine,
         }
 
         /* skip slots with explicit mismatch */
-        if (props->has_thread_id && props->thread_id != slot->props.thread_id) {
+        if (props->has_socket_id && props->socket_id != slot->props.socket_id) {
                 continue;
         }
 
-        if (props->has_core_id && props->core_id != slot->props.core_id) {
+        if (props->has_core_id) {
+            if (props->core_id != slot->props.core_id) {
                 continue;
+            }
+            if (slot->props.has_node_id) {
+                /* we have a node where our core is already assigned */
+                previous_props = &slot->props;
+            }
         }
 
-        if (props->has_socket_id && props->socket_id != slot->props.socket_id) {
+        if (props->has_thread_id && props->thread_id != slot->props.thread_id) {
                 continue;
         }
 
+        /* check current thread matches node of the thread of the same core */
+        if (previous_props && previous_props->has_node_id &&
+            previous_props->node_id != props->node_id) {
+            char *cpu_str = cpu_props_to_string(props);
+            char *node_str = cpu_props_to_string(previous_props);
+            error_setg(errp,  "Invalid node-id=%"PRIu64" of [%s]: core-id "
+                              "[%s] is already assigned to node-id %"PRIu64,
+                              props->node_id, cpu_str,
+                              node_str, previous_props->node_id);
+            g_free(cpu_str);
+            g_free(node_str);
+            return;
+        }
+
         /* reject assignment if slot is already assigned, for compatibility
          * of legacy cpu_index mapping with SPAPR core based mapping do not
          * error out if cpu thread and matched core have the same node-id */
diff --git a/tests/numa-test.c b/tests/numa-test.c
index 5280573fc992..a7c3c5b4dee8 100644
--- a/tests/numa-test.c
+++ b/tests/numa-test.c
@@ -112,7 +112,7 @@ static void pc_numa_cpu(const void *data)
         "-numa cpu,node-id=1,socket-id=0 "
         "-numa cpu,node-id=0,socket-id=1,core-id=0 "
         "-numa cpu,node-id=0,socket-id=1,core-id=1,thread-id=0 "
-        "-numa cpu,node-id=1,socket-id=1,core-id=1,thread-id=1");
+        "-numa cpu,node-id=0,socket-id=1,core-id=1,thread-id=1");
     qtest_start(cli);
     cpus = get_cpus(&resp);
     g_assert(cpus);
@@ -141,7 +141,7 @@ static void pc_numa_cpu(const void *data)
         } else if (socket == 1 && core == 1 && thread == 0) {
             g_assert_cmpint(node, ==, 0);
         } else if (socket == 1 && core == 1 && thread == 1) {
-            g_assert_cmpint(node, ==, 1);
+            g_assert_cmpint(node, ==, 0);
         } else {
             g_assert(false);
         }
-- 
2.20.1

Re: [Qemu-devel] [RFC 4/4] numa: check threads of the same core are on the same node

[David Gibson]

[-- Attachment #1: Type: text/plain, Size: 4988 bytes --]

On Tue, Feb 12, 2019 at 10:48:27PM +0100, Laurent Vivier wrote:
> A core cannot be split between two nodes.
> To check if a thread of the same core has already been assigned to a node,
> this patch reverses the numa topology checking order and exits if the
> topology is not valid.

I'm not entirely sure if this makes sense to enforce generically.

It's certainly true for PAPR - we have no way to represent threads
with different NUMA nodes to the guest.

It probably makes sense for everything - the whole point of threading
is to take better advantage of latencies accessing memory, so it seems
implausible that the threads would have different paths to memory.

But... there are some pretty weird setups out there, so I'm not sure
it's a good idea to enforce a restriction generically that's not
actually inherent in the structure of the problem.

> 
> Update test/numa-test accordingly.
> 
> Fixes: 722387e78daf ("spapr: get numa node mapping from possible_cpus instead of numa_get_node_for_cpu()")
> Cc: imammedo@redhat.com
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  hw/core/machine.c | 27 ++++++++++++++++++++++++---
>  tests/numa-test.c |  4 ++--
>  2 files changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index a2c29692b55e..c0a556b0dce7 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -602,6 +602,7 @@ void machine_set_cpu_numa_node(MachineState *machine,
>      MachineClass *mc = MACHINE_GET_CLASS(machine);
>      bool match = false;
>      int i;
> +    const CpuInstanceProperties *previous_props = NULL;
>  
>      if (!mc->possible_cpu_arch_ids) {
>          error_setg(errp, "mapping of CPUs to NUMA node is not supported");
> @@ -634,18 +635,38 @@ void machine_set_cpu_numa_node(MachineState *machine,
>          }
>  
>          /* skip slots with explicit mismatch */
> -        if (props->has_thread_id && props->thread_id != slot->props.thread_id) {
> +        if (props->has_socket_id && props->socket_id != slot->props.socket_id) {
>                  continue;
>          }
>  
> -        if (props->has_core_id && props->core_id != slot->props.core_id) {
> +        if (props->has_core_id) {
> +            if (props->core_id != slot->props.core_id) {
>                  continue;
> +            }
> +            if (slot->props.has_node_id) {
> +                /* we have a node where our core is already assigned */
> +                previous_props = &slot->props;
> +            }
>          }
>  
> -        if (props->has_socket_id && props->socket_id != slot->props.socket_id) {
> +        if (props->has_thread_id && props->thread_id != slot->props.thread_id) {
>                  continue;
>          }
>  
> +        /* check current thread matches node of the thread of the same core */
> +        if (previous_props && previous_props->has_node_id &&
> +            previous_props->node_id != props->node_id) {
> +            char *cpu_str = cpu_props_to_string(props);
> +            char *node_str = cpu_props_to_string(previous_props);
> +            error_setg(errp,  "Invalid node-id=%"PRIu64" of [%s]: core-id "
> +                              "[%s] is already assigned to node-id %"PRIu64,
> +                              props->node_id, cpu_str,
> +                              node_str, previous_props->node_id);
> +            g_free(cpu_str);
> +            g_free(node_str);
> +            return;
> +        }
> +
>          /* reject assignment if slot is already assigned, for compatibility
>           * of legacy cpu_index mapping with SPAPR core based mapping do not
>           * error out if cpu thread and matched core have the same node-id */
> diff --git a/tests/numa-test.c b/tests/numa-test.c
> index 5280573fc992..a7c3c5b4dee8 100644
> --- a/tests/numa-test.c
> +++ b/tests/numa-test.c
> @@ -112,7 +112,7 @@ static void pc_numa_cpu(const void *data)
>          "-numa cpu,node-id=1,socket-id=0 "
>          "-numa cpu,node-id=0,socket-id=1,core-id=0 "
>          "-numa cpu,node-id=0,socket-id=1,core-id=1,thread-id=0 "
> -        "-numa cpu,node-id=1,socket-id=1,core-id=1,thread-id=1");
> +        "-numa cpu,node-id=0,socket-id=1,core-id=1,thread-id=1");
>      qtest_start(cli);
>      cpus = get_cpus(&resp);
>      g_assert(cpus);
> @@ -141,7 +141,7 @@ static void pc_numa_cpu(const void *data)
>          } else if (socket == 1 && core == 1 && thread == 0) {
>              g_assert_cmpint(node, ==, 0);
>          } else if (socket == 1 && core == 1 && thread == 1) {
> -            g_assert_cmpint(node, ==, 1);
> +            g_assert_cmpint(node, ==, 0);
>          } else {
>              g_assert(false);
>          }

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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