linux-kernel - Re: [PATCH v3 4/7] x86/tlb: add tlb flush all factor for specific CPUs

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Message-ID: <4FA9D07D.8000401@intel.com>
Date:	Wed, 09 May 2012 10:03:41 +0800
From:	Alex Shi <alex.shi@...el.com>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC:	mgorman@...e.de, npiggin@...il.com, tglx@...utronix.de,
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Subject: Re: [PATCH v3 4/7] x86/tlb: add tlb flush all factor for specific
 CPUs

On 05/08/2012 11:08 PM, Peter Zijlstra wrote:

> On Tue, 2012-05-08 at 22:03 +0800, Alex Shi wrote:
>> +void intel_tlb_flushall_factor_set(struct cpuinfo_x86 *c)
>> +{
>> +       switch (c->x86_model) {
>> +       case 15: /* original 65 nm celeron/pentium/core2/xeon, "Merom"/"Conroe" */
>> +               tlb_flushall_factor = 0;
>> +               break;
> 
> Why isn't this is the bottom list of core chips?


It was tested. but the bottom list cpu was not tested.

> 
>> +       case 26: /* 45 nm nehalem, "Bloomfield" */
>> +       case 30: /* 45 nm nehalem, "Lynnfield" */
>> +       case 37: /* 32 nm nehalem, "Clarkdale" */
>> +       case 44: /* 32 nm nehalem, "Gulftown" */
>> +       case 46: /* 45 nm nehalem-ex, "Beckton" */
>> +               tlb_flushall_factor = 64;
>> +               break;
>> +       case 42: /* SandyBridge */
>> +       case 45: /* SandyBridge, "Romely-EP" */
>> +               tlb_flushall_factor = 32;
>> +               break;
>> +       case 28: /* Atom */
>> +       case 47: /* 32 nm Xeon E7 */
> 
> This is a wsm-ex, right? Why isn't it listed with the other nehalems?


I don't know this. Thanks for this info

> 
>> +       case 14: /* 65 nm core solo/duo, "Yonah" */
>> +       case 22: /* single-core 65 nm celeron/core2solo "Merom-L"/"Conroe-L" */
>> +       case 23: /* current 45 nm celeron/core2/xeon "Penryn"/"Wolfdale" */
>> +       case 29: /* six-core 45 nm xeon "Dunnington" */
> 
> So never use invlpg for Atom/Core/Core2?


Uh, I will remove the CPU list if they weren't tested.

> 
>> +       default:
>> +               tlb_flushall_factor = 0;
>> +       }
>> +}
> 
> 
>> @@ -364,7 +363,8 @@ flush_all:
>>                         act_entries = tlb_entries > mm->total_vm ?
>>                                         mm->total_vm : tlb_entries;
>>  
>> +                       if ((end - start)/PAGE_SIZE >
>> +                                       act_entries/tlb_flushall_factor) 
> 
> You're doing an actual full division, wouldn't a shift be better?


Thanks!

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