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Re: [PATCH] MIPS: Keep TLB cache hot while flushing

To: Ralf Baechle <ralf@linux-mips.org>
Subject: Re: [PATCH] MIPS: Keep TLB cache hot while flushing
From: Hillf Danton <dhillf@gmail.com>
Date: Sun, 6 Nov 2011 13:08:28 +0800
Cc: David Daney <ddaney.cavm@gmail.com>, linux-mips@linux-mips.org
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On Fri, Nov 4, 2011 at 10:56 PM, Ralf Baechle <ralf@linux-mips.org> wrote:
> On Fri, Oct 28, 2011 at 09:16:29AM -0700, David Daney wrote:
>
>> >If we only flush the TLB of the given huge page, the TLB cache remains hot 
>> >for
>> >the relevant mm as it is, and less will be refilled after flush, huge or 
>> >not.
>> >
>> >As always all comments and ideas welcome.
>> >
>>
>> I haven't tested it, but it looks correct.  When I wrote the
>> original flush_tlb_mm(), I was in a hurry and was more concerned
>> about maintaining TLB consistency, rather than performance.
>
> Yes, looks sane and like an obvious performance improvment.  but as always
> with TLB stuff I'm paranoid so I've applied this to my 3.3 queue for it to
> be tested well.
>

Thanks Ralf and David:)

> Hillf, do you have any benchmark numbers for this?
>

Simple application related to libhugetlbfs works as it was after this patch
applied. Unlike x86, MIPS box is rare resource, and I have to ask David, the
author of MIPS huge TLB, to benchmark this patch, and to test GUP on Cavium
chips as well.

Btw, the patch for THP is prepared, and I am chasing box for test. Would you
please, David, take a look at it before posting?

Thanks

Hillf

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