[Qemu-devel] [Update PATCH V2] x86: Increase max vcpu number to 8192

Lan Tianyu posted 1 patch 6 years, 7 months ago
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hw/i386/pc_q35.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
[Qemu-devel] [Update PATCH V2] x86: Increase max vcpu number to 8192
Posted by Lan Tianyu 6 years, 7 months ago
Intel Xeon phi chip will support 352 logical threads. For HPC
usage case, it will create a huge VM with vcpus number as same as host
cpus. This patch is to increase max vcpu number from 288 to 8192 which
is current default maximum cpu number for Linux kernel.

Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
---
Change since v1:
	* Bump max vcpu number from 352 to 8192
	* Add compat support for new max vcpu limitation

 hw/i386/pc_q35.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 169a214..e093601 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -299,13 +299,21 @@ static void pc_q35_machine_options(MachineClass *m)
     m->default_display = "std";
     m->no_floppy = 1;
     m->has_dynamic_sysbus = true;
-    m->max_cpus = 288;
+    m->max_cpus = 8192;
 }
 
+static void pc_q35_2_11_machine_options(MachineClass *m)
+{
+     pc_q35_machine_options(m);
+     m->alias = "q35";
+}
+DEFINE_Q35_MACHINE(v2_11, "pc-q35-2.11", NULL,
+                   pc_q35_2_11_machine_options);
+
 static void pc_q35_2_10_machine_options(MachineClass *m)
 {
-    pc_q35_machine_options(m);
-    m->alias = "q35";
+    pc_q35_2_11_machine_options(m);
+    m->max_cpus = 288;
     m->numa_auto_assign_ram = numa_legacy_auto_assign_ram;
 }
 
-- 
1.8.3.1


Re: [Qemu-devel] [Update PATCH V2] x86: Increase max vcpu number to 8192
Posted by Eduardo Habkost 6 years, 7 months ago
On Thu, Aug 10, 2017 at 10:26:06PM -0400, Lan Tianyu wrote:
> Intel Xeon phi chip will support 352 logical threads. For HPC
> usage case, it will create a huge VM with vcpus number as same as host
> cpus. This patch is to increase max vcpu number from 288 to 8192 which
> is current default maximum cpu number for Linux kernel.
> 
> Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
> ---
> Change since v1:
> 	* Bump max vcpu number from 352 to 8192
> 	* Add compat support for new max vcpu limitation
> 
>  hw/i386/pc_q35.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 169a214..e093601 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -299,13 +299,21 @@ static void pc_q35_machine_options(MachineClass *m)
>      m->default_display = "std";
>      m->no_floppy = 1;
>      m->has_dynamic_sysbus = true;
> -    m->max_cpus = 288;
> +    m->max_cpus = 8192;
>  }
>  
> +static void pc_q35_2_11_machine_options(MachineClass *m)
> +{
> +     pc_q35_machine_options(m);
> +     m->alias = "q35";
> +}
> +DEFINE_Q35_MACHINE(v2_11, "pc-q35-2.11", NULL,
> +                   pc_q35_2_11_machine_options);
> +
>  static void pc_q35_2_10_machine_options(MachineClass *m)
>  {
> -    pc_q35_machine_options(m);
> -    m->alias = "q35";
> +    pc_q35_2_11_machine_options(m);

You need m->alias=NULL here.

> +    m->max_cpus = 288;
>      m->numa_auto_assign_ram = numa_legacy_auto_assign_ram;
>  }
>  

Please add the pc-*-2.11 machine-types in a separate patch.  This
way we can add the new machine-types in other series/trees and
deal more easily with conflicts.

You can use commit 465238d9f873a6251223db1669aa4766822a8783
("pc: add 2.10 machine type") as reference.

-- 
Eduardo