[PATCH] x86/tsc: Append description for 'tsc=unstable' boot parameter

[PATCH] x86/tsc: Append description for 'tsc=unstable' boot parameter

[Dou Liyang]

Commit 8309f86cd41e ("x86/tsc: Provide 'tsc=unstable' boot parameter") adds
a new parameter 'tsc=unstable', but doesn't add some description to guide
users.

Append the description of 'tsc=unstable' at the end of 'tsc=' section.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 9a84483..33e83b6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4196,6 +4196,9 @@
 			Used to run time disable IRQ_TIME_ACCOUNTING on any
 			platforms where RDTSC is slow and this accounting
 			can add overhead.
+			[x86] unstable: mark tsc clocksource as unstable, this
+			marks the TSC unconditionally unstable at bootup and
+			avoids any further wobbles once the TSC watchdog notices.
 
 	turbografx.map[2|3]=	[HW,JOY]
 			TurboGraFX parallel port interface
-- 
2.5.5

Re: [PATCH] x86/tsc: Append description for 'tsc=unstable' boot parameter

[Pavel Tatashin]

Hi Dou,

Have you tested tsc=unstable with your DR setup? Is it working as
expected? I mean instead of previous "notsc"?

Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>

Thank you,
Pavel

On Mon, Oct 9, 2017 at 5:03 AM, Dou Liyang <douly.fnst@cn.fujitsu.com> wrote:
> Commit 8309f86cd41e ("x86/tsc: Provide 'tsc=unstable' boot parameter") adds
> a new parameter 'tsc=unstable', but doesn't add some description to guide
> users.
>
> Append the description of 'tsc=unstable' at the end of 'tsc=' section.
>
> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
> ---
>  Documentation/admin-guide/kernel-parameters.txt | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 9a84483..33e83b6 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4196,6 +4196,9 @@
>                         Used to run time disable IRQ_TIME_ACCOUNTING on any
>                         platforms where RDTSC is slow and this accounting
>                         can add overhead.
> +                       [x86] unstable: mark tsc clocksource as unstable, this
> +                       marks the TSC unconditionally unstable at bootup and
> +                       avoids any further wobbles once the TSC watchdog notices.
>
>         turbografx.map[2|3]=    [HW,JOY]
>                         TurboGraFX parallel port interface
> --
> 2.5.5
>
>
>

Re: [PATCH] x86/tsc: Append description for 'tsc=unstable' boot parameter

[Dou Liyang]

Hi Pavel,

At 10/09/2017 08:25 PM, Pavel Tatashin wrote:
> Hi Dou,
>
> Have you tested tsc=unstable with your DR setup? Is it working as
> expected? I mean instead of previous "notsc"?

Not yet, I have applied for the machine, I'll start testing once I have
access to it. And I am looking at this part of code to prepare for the
test. :-)

>
> Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
>
Thank you very much.

Thanks,
	dou.

> Thank you,
> Pavel
>
> On Mon, Oct 9, 2017 at 5:03 AM, Dou Liyang <douly.fnst@cn.fujitsu.com> wrote:
>> Commit 8309f86cd41e ("x86/tsc: Provide 'tsc=unstable' boot parameter") adds
>> a new parameter 'tsc=unstable', but doesn't add some description to guide
>> users.
>>
>> Append the description of 'tsc=unstable' at the end of 'tsc=' section.
>>
>> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
>> ---
>>  Documentation/admin-guide/kernel-parameters.txt | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index 9a84483..33e83b6 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -4196,6 +4196,9 @@
>>                         Used to run time disable IRQ_TIME_ACCOUNTING on any
>>                         platforms where RDTSC is slow and this accounting
>>                         can add overhead.
>> +                       [x86] unstable: mark tsc clocksource as unstable, this
>> +                       marks the TSC unconditionally unstable at bootup and
>> +                       avoids any further wobbles once the TSC watchdog notices.
>>
>>         turbografx.map[2|3]=    [HW,JOY]
>>                         TurboGraFX parallel port interface
>> --
>> 2.5.5
>>
>>
>>
>
>
>

[tip:sched/core] x86/tsc: Append the 'tsc=' description for the 'tsc=unstable' boot parameter

[tip-bot for Dou Liyang]

Commit-ID:  6be53520ad8f87dc748f381e4e8e6a846a4b466b
Gitweb:     https://git.kernel.org/tip/6be53520ad8f87dc748f381e4e8e6a846a4b466b
Author:     Dou Liyang <douly.fnst@cn.fujitsu.com>
AuthorDate: Mon, 9 Oct 2017 17:03:33 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 10 Oct 2017 11:45:42 +0200

x86/tsc: Append the 'tsc=' description for the 'tsc=unstable' boot parameter

Commit:

  8309f86cd41e ("x86/tsc: Provide 'tsc=unstable' boot parameter")

added a new 'tsc=unstable' parameter, but didn't document it.

Document it.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <corbet@lwn.net>
Cc: <pasha.tatashin@oracle.com>
Cc: <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1507539813-11420-1-git-send-email-douly.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 Documentation/admin-guide/kernel-parameters.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 0549662..6b99c8b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4194,6 +4194,9 @@
 			Used to run time disable IRQ_TIME_ACCOUNTING on any
 			platforms where RDTSC is slow and this accounting
 			can add overhead.
+			[x86] unstable: mark the TSC clocksource as unstable, this
+			marks the TSC unconditionally unstable at bootup and
+			avoids any further wobbles once the TSC watchdog notices.
 
 	turbografx.map[2|3]=	[HW,JOY]
 			TurboGraFX parallel port interface