* [PATCH] docs: Update nosmt support for arm64
@ 2026-04-17 3:25 Jinjie Ruan
2026-05-11 6:17 ` Jinjie Ruan
0 siblings, 1 reply; 2+ messages in thread
From: Jinjie Ruan @ 2026-04-17 3:25 UTC (permalink / raw)
To: corbet, skhan, akpm, bp, rdunlap, pmladek, pawan.kumar.gupta,
feng.tang, dapeng1.mi, kees, elver, paulmck, lirongqing,
safinaskar, bhelgaas, linux-doc, linux-kernel, skelley
Cc: ruanjinjie
commit eed4583bcf9a6 ("arm64: Kconfig: Enable HOTPLUG_SMT") enable
HOTPLUG_SMT for SMT control for arm64, but the documentation was
not updated accordingly to reflect that ARM64 now supports control SMT
via boot parameter and sysfs knobs:
1. Boot parameters:
nosmt: Disable SMT, can be enabled via sysfs knobs.
nosmt=force: Disable SMT, cannot be enabled via sysfs knobs.
2. Runtime sysfs controls:
Write "on", "off", "forceoff" or the number of SMT threads (1, 2, ...)
to /sys/devices/system/cpu/smt/control.
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
Documentation/admin-guide/kernel-parameters.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cb850e5290c2..6a73eb5abae9 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4661,7 +4661,7 @@ Kernel parameters
nosmt [KNL,MIPS,PPC,EARLY] Disable symmetric multithreading (SMT).
Equivalent to smt=1.
- [KNL,LOONGARCH,X86,PPC,S390] Disable symmetric multithreading (SMT).
+ [KNL,LOONGARCH,X86,ARM64,PPC,S390] Disable symmetric multithreading (SMT).
nosmt=force: Force disable SMT, cannot be undone
via the sysfs control file.
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] docs: Update nosmt support for arm64
2026-04-17 3:25 [PATCH] docs: Update nosmt support for arm64 Jinjie Ruan
@ 2026-05-11 6:17 ` Jinjie Ruan
0 siblings, 0 replies; 2+ messages in thread
From: Jinjie Ruan @ 2026-05-11 6:17 UTC (permalink / raw)
To: corbet, skhan, akpm, bp, rdunlap, pmladek, pawan.kumar.gupta,
feng.tang, dapeng1.mi, kees, elver, paulmck, lirongqing,
safinaskar, bhelgaas, linux-doc, linux-kernel, skelley
Gentle ping.
On 4/17/2026 11:25 AM, Jinjie Ruan wrote:
> commit eed4583bcf9a6 ("arm64: Kconfig: Enable HOTPLUG_SMT") enable
> HOTPLUG_SMT for SMT control for arm64, but the documentation was
> not updated accordingly to reflect that ARM64 now supports control SMT
> via boot parameter and sysfs knobs:
>
> 1. Boot parameters:
>
> nosmt: Disable SMT, can be enabled via sysfs knobs.
> nosmt=force: Disable SMT, cannot be enabled via sysfs knobs.
>
> 2. Runtime sysfs controls:
>
> Write "on", "off", "forceoff" or the number of SMT threads (1, 2, ...)
> to /sys/devices/system/cpu/smt/control.
>
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index cb850e5290c2..6a73eb5abae9 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4661,7 +4661,7 @@ Kernel parameters
> nosmt [KNL,MIPS,PPC,EARLY] Disable symmetric multithreading (SMT).
> Equivalent to smt=1.
>
> - [KNL,LOONGARCH,X86,PPC,S390] Disable symmetric multithreading (SMT).
> + [KNL,LOONGARCH,X86,ARM64,PPC,S390] Disable symmetric multithreading (SMT).
> nosmt=force: Force disable SMT, cannot be undone
> via the sysfs control file.
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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