[PATCH] x86: Removing unnecessary check in detect_ht

[PATCH] x86: Removing unnecessary check in detect_ht

[Rao, Nikhil]

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This patch removes a check that prevents correct CPU topology setup
when cpuid extensions for topology enumeration are not supported and
the number of processors reported to the OS is smaller than 
smp_num_siblings

Signed-off-by: Nikhil P Rao <nikhil.rao@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
CC: <stable@kernel.org>
---
 arch/x86/kernel/cpu/common.c |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index e2ced007..6547084 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -458,13 +458,6 @@ void __cpuinit detect_ht(struct cpuinfo_x86 *c)
        if (smp_num_siblings <= 1)
                goto out;
 
-       if (smp_num_siblings > nr_cpu_ids) {
-               pr_warning("CPU: Unsupported number of siblings %d",
-                          smp_num_siblings);
-               smp_num_siblings = 1;
-               return;
-       }
-
        index_msb = get_count_order(smp_num_siblings);
        c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);
 
-- 
1.7.4.2
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Re: [PATCH] x86: Removing unnecessary check in detect_ht

[Ingo Molnar]

* Rao, Nikhil <nikhil.rao@intel.com> wrote:

> This patch removes a check that prevents correct CPU topology setup
> when cpuid extensions for topology enumeration are not supported and
> the number of processors reported to the OS is smaller than 
> smp_num_siblings

What bad effect was observed, exactly? An annoying warning in the bootlog and 
incorrect scheduler domain setup (SMP instead of SMT) - or something else as 
well?

Thanks,

	Ingo

RE: [PATCH] x86: Removing unnecessary check in detect_ht

[Rao, Nikhil]

Nothing apart from what you mention - bootlog message and SMP instead of SMT.

Nikhil

> -----Original Message-----
> From: Ingo Molnar [mailto:mingo@elte.hu]
> Sent: Wednesday, May 18, 2011 2:08 PM
> To: Rao, Nikhil
> Cc: tglx@linutronix.de; mingo@redhat.com; hpa@zytor.com;
> x86@kernel.org; Siddha, Suresh B; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] x86: Removing unnecessary check in detect_ht
> 
> 
> * Rao, Nikhil <nikhil.rao@intel.com> wrote:
> 
> > This patch removes a check that prevents correct CPU topology setup
> > when cpuid extensions for topology enumeration are not supported and
> > the number of processors reported to the OS is smaller than
> > smp_num_siblings
> 
> What bad effect was observed, exactly? An annoying warning in the
> bootlog and
> incorrect scheduler domain setup (SMP instead of SMT) - or something
> else as
> well?
> 
> Thanks,
> 
> 	Ingo

Re: [PATCH] x86: Removing unnecessary check in detect_ht

[Ingo Molnar]

* Rao, Nikhil <nikhil.rao@intel.com> wrote:

> Nothing apart from what you mention - bootlog message and SMP instead of SMT.

Mind putting this information into the changelog and repost the patch? It's 
arguably the kind of practical information that most readers of changelogs are 
interested in.

Thanks,

	Ingo

RE: [PATCH] x86: Removing unnecessary check in detect_ht

[Rao, Nikhil]

Hi Ingo,

Reposting as per your feedback.

Thanks,
Nikhil

---
This patch removes a check that causes incorrect scheduler domain
setup (SMP instead of SMT) and bootlog warning messages when cpuid
extensions for topology enumeration are not supported and the number
of processors reported to the OS is smaller than smp_num_siblings

Signed-off-by: Nikhil P Rao <nikhil.rao@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
---
 arch/x86/kernel/cpu/common.c |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index e2ced007..6547084 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -458,13 +458,6 @@ void __cpuinit detect_ht(struct cpuinfo_x86 *c)
        if (smp_num_siblings <= 1)
                goto out;
 
-       if (smp_num_siblings > nr_cpu_ids) {
-               pr_warning("CPU: Unsupported number of siblings %d",
-                          smp_num_siblings);
-               smp_num_siblings = 1;
-               return;
-       }
-
        index_msb = get_count_order(smp_num_siblings);
        c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);
 
-- 
1.7.4.2

> -----Original Message-----
> From: Ingo Molnar [mailto:mingo@elte.hu]
> Sent: Wednesday, May 18, 2011 2:24 PM
> To: Rao, Nikhil
> Cc: tglx@linutronix.de; mingo@redhat.com; hpa@zytor.com;
> x86@kernel.org; Siddha, Suresh B; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] x86: Removing unnecessary check in detect_ht
> 
> 
> * Rao, Nikhil <nikhil.rao@intel.com> wrote:
> 
> > Nothing apart from what you mention - bootlog message and SMP instead
> of SMT.
> 
> Mind putting this information into the changelog and repost the patch?
> It's
> arguably the kind of practical information that most readers of
> changelogs are
> interested in.
> 
> Thanks,
> 
> 	Ingo

Re: [PATCH] x86: Removing unnecessary check in detect_ht

[Ingo Molnar]

* Rao, Nikhil <nikhil.rao@intel.com> wrote:

> Hi Ingo,
> 
> Reposting as per your feedback.

Please send a patch that applies to the x86 tree cleanly:

  http://people.redhat.com/mingo/tip.git/README

Thanks,

	Ingo

RE: [PATCH] x86: Removing unnecessary check in detect_ht

[Rao, Nikhil]

This patch removes a check that causes incorrect scheduler domain setup (SMP instead of SMT) and bootlog warning messages when cpuid extensions for topology enumeration are not supported and the number of processors reported to the OS is smaller than smp_num_siblings

Signed-off-by: Nikhil P Rao <nikhil.rao@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
---
 arch/x86/kernel/cpu/common.c |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index cbc70a2..d2bcd54 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -477,13 +477,6 @@ void __cpuinit detect_ht(struct cpuinfo_x86 *c)
        if (smp_num_siblings <= 1)
                goto out;
 
-       if (smp_num_siblings > nr_cpu_ids) {
-               pr_warning("CPU: Unsupported number of siblings %d",
-                          smp_num_siblings);
-               smp_num_siblings = 1;
-               return;
-       }
-
        index_msb = get_count_order(smp_num_siblings);
        c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);
 
--
1.7.4.2

> -----Original Message-----
> From: Ingo Molnar [mailto:mingo@elte.hu]
> Sent: Thursday, May 19, 2011 11:10 AM
> To: Rao, Nikhil
> Cc: tglx@linutronix.de; mingo@redhat.com; hpa@zytor.com;
> x86@kernel.org; Siddha, Suresh B; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] x86: Removing unnecessary check in detect_ht
> 
> * Rao, Nikhil <nikhil.rao@intel.com> wrote:
> 
> > Hi Ingo,
> >
> > Reposting as per your feedback.
> 
> Please send a patch that applies to the x86 tree cleanly:
> 
>   http://people.redhat.com/mingo/tip.git/README
> 
> Thanks,
> 
> 	Ingo

Re: [PATCH] x86: Removing unnecessary check in detect_ht

[Ingo Molnar]

* Rao, Nikhil <nikhil.rao@intel.com> wrote:

> This patch removes a check that causes incorrect scheduler domain setup (SMP instead of SMT) and bootlog warning messages when cpuid extensions for topology enumeration are not supported and the number of processors reported to the OS is smaller than smp_num_siblings
> 
> Signed-off-by: Nikhil P Rao <nikhil.rao@intel.com>
> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
> ---
>  arch/x86/kernel/cpu/common.c |    7 -------
>  1 files changed, 0 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index cbc70a2..d2bcd54 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -477,13 +477,6 @@ void __cpuinit detect_ht(struct cpuinfo_x86 *c)
>         if (smp_num_siblings <= 1)
>                 goto out;
>  
> -       if (smp_num_siblings > nr_cpu_ids) {
> -               pr_warning("CPU: Unsupported number of siblings %d",
> -                          smp_num_siblings);
> -               smp_num_siblings = 1;
> -               return;
> -       }
> -

Your patch does not apply because it's whitespace damaged (all tabs got 
converted to spaces). Please see Documentation/email-clients.txt.

Thanks,

	Ingo

Re: [PATCH] x86: Removing unnecessary check in detect_ht

[Nikhil P Rao]

This patch removes a check that causes incorrect scheduler domain
setup (SMP instead of SMT) and bootlog warning messages when cpuid
extensions for topology enumeration are not supported and the number
of processors reported to the OS is smaller than smp_num_siblings

Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Nikhil P Rao <nikhil.rao@intel.com>
---
 arch/x86/kernel/cpu/common.c |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index cbc70a2..d2bcd54 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -477,13 +477,6 @@ void __cpuinit detect_ht(struct cpuinfo_x86 *c)
 	if (smp_num_siblings <= 1)
 		goto out;
 
-	if (smp_num_siblings > nr_cpu_ids) {
-		pr_warning("CPU: Unsupported number of siblings %d",
-			   smp_num_siblings);
-		smp_num_siblings = 1;
-		return;
-	}
-
 	index_msb = get_count_order(smp_num_siblings);
 	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);
 
-- 
1.7.4.4


On Fri, 2011-05-20 at 13:46 +0200, Ingo Molnar wrote:

> Your patch does not apply because it's whitespace damaged (all tabs got 
> converted to spaces). Please see Documentation/email-clients.txt.
> 
> Thanks,
> 
> 	Ingo

[tip:x86/urgent] x86: Remove unnecessary check in detect_ht()

[tip-bot for Nikhil P Rao]

Commit-ID:  8b27f2ff7a24f0735c96055e676872f05398d99b
Gitweb:     http://git.kernel.org/tip/8b27f2ff7a24f0735c96055e676872f05398d99b
Author:     Nikhil P Rao <nikhil.rao@intel.com>
AuthorDate: Wed, 25 May 2011 10:18:41 -0700
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 25 May 2011 23:01:08 +0200

x86: Remove unnecessary check in detect_ht()

This patch removes a check that causes incorrect scheduler
domain setup (SMP instead of SMT) and bootlog warning messages
when cpuid extensions for topology enumeration are not supported
and the number of processors reported to the OS is smaller than
smp_num_siblings.

Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Nikhil P Rao <nikhil.rao@intel.com>
Link: http://lkml.kernel.org/r/1306343921.19325.1.camel@fedora13
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/common.c |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index c8b4162..53f02f5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -477,13 +477,6 @@ void __cpuinit detect_ht(struct cpuinfo_x86 *c)
 	if (smp_num_siblings <= 1)
 		goto out;
 
-	if (smp_num_siblings > nr_cpu_ids) {
-		pr_warning("CPU: Unsupported number of siblings %d",
-			   smp_num_siblings);
-		smp_num_siblings = 1;
-		return;
-	}
-
 	index_msb = get_count_order(smp_num_siblings);
 	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);