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From: "H. Peter Anvin" <hpa@zytor.com>
To: David Daney <david.daney@cavium.com>
Cc: Venkatesh Pallipadi <venki@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Suresh Siddha <suresh.b.siddha@intel.com>,
	Aaron Durbin <adurbin@google.com>, Paul Turner <pjt@google.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC] Extend mwait idle to optimize away IPIs when possible
Date: Mon, 06 Feb 2012 17:24:21 -0800	[thread overview]
Message-ID: <4F307D45.1050404@zytor.com> (raw)
In-Reply-To: <4F306FAF.7020500@cavium.com>

On 02/06/2012 04:26 PM, David Daney wrote:
> On 02/06/2012 12:42 PM, Venkatesh Pallipadi wrote:
> [...]
>> index 5bed94e..6a56cb0 100644
>> --- a/arch/x86/Kconfig
>> +++ b/arch/x86/Kconfig
>> @@ -170,6 +170,11 @@ config GENERIC_TIME_VSYSCALL
>>       bool
>>       default X86_64
>>
>> +config AVOID_IPI_ON_IDLE
>> +    bool
>> +    depends on X86_64
>> +    default X86_64
>> +
> 
> Can you get rid of this part...
> 
>>   config ARCH_HAS_CPU_RELAX
>>       def_bool y
>>
> [...]
>> diff --git a/arch/x86/kernel/acpi/cstate.c
>> b/arch/x86/kernel/acpi/cstate.c
>> index f50e7fb..340c4e9 100644
>> --- a/arch/x86/kernel/acpi/cstate.c
>> +++ b/arch/x86/kernel/acpi/cstate.c
>> @@ -161,6 +161,14 @@ EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);
>>    */
>>   void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
>>   {
>> +#ifdef CONFIG_AVOID_IPI_ON_IDLE
> 
> 
> ... and change all of these to #ifdef CONFIG_64BIT
> 
>> +    int oldval, cpu = smp_processor_id();
>> +

Why should this be 64-bit specific??

	-hpa


-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  reply	other threads:[~2012-02-07  1:25 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-06 20:42 Venkatesh Pallipadi
2012-02-06 21:02 ` Peter Zijlstra
2012-02-06 21:26   ` Venki Pallipadi
2012-02-07  0:26 ` David Daney
2012-02-07  1:24   ` H. Peter Anvin [this message]
2012-02-07  1:34     ` David Daney
2012-02-07  1:45       ` H. Peter Anvin
2012-02-07  2:03         ` Venki Pallipadi
2012-02-07  2:24 ` Suresh Siddha
2012-02-07 21:39   ` Venki Pallipadi
2012-02-08  6:51 ` Yong Zhang
2012-02-08 23:28   ` Venki Pallipadi
2012-02-09  2:18     ` Yong Zhang
2012-02-10  2:17       ` Venki Pallipadi
2012-02-13  5:27         ` Yong Zhang
2012-02-10 19:19 ` Peter Zijlstra
2012-02-11  2:11   ` Venki Pallipadi
2012-02-11  3:09     ` Peter Zijlstra
2012-02-13  5:34     ` Yong Zhang
2012-02-14 13:52       ` Peter Zijlstra
2012-02-15  1:39         ` Yong Zhang
2012-02-15  2:32         ` Venki Pallipadi

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