I really want to know why I cannot change it.
It locked by hardware or os?
If I change and recompile the kernel, may I make it support?
Can I change hugepagesize to bigger or smaller
than 16MB on PPC? Such as 32MB or 4MB.
Any help will be appreciated.
--Easley
------------------ Original ------------------
From: "bill4carson"<bill4car...@gmail.com>;
Date: Tue, Nov 15, 2011 09:36 AM
To: "Eric B Munson"<emun...@mgebm.net>;
Cc: "Easley"<ugi...@gmail.com>;
"libhugetlbfs-devel"<libhugetlbfs-devel@lists.sourceforge.net>;
Subject: Re: [Libhugetlbfs-devel] How to change the hugepagesize?
On 2011年11月14日 22:03, Eric B Munson wrote:
> On Mon, 14 Nov 2011, bill4carson wrote:
>
>>
>> On 2011年11月14日 16:00, Easley wrote:
>>> I add "hugepagesz=1M hugepages=32" to grub.conf.
>>> The "hugepagesz=16M" doesn't take effect.
>>> The "hugepages=32" take effect.
>>> What type is hardware support that?
>>>
>>> Any help will be appreciated.
>>>
>>> --Easley
>> hugepagesz=16M only work for x86_64 platform,
>> check arch/x86/mm/hugetlbpage.c setup_hugepagesz
>>
>> guess your machine is an 32 bit x86.
> I guess my replies aren't getting through...
>
> 16MB pages are only supported by POWERPC, with a 2MB default size I you are
> either running x86_64 or x86 with PAE. On the RHEL 5.4 kernel that is the
> only
> valid page size for that arch.
>
> Eric
>
Hi, Eric
Thanks for you clarification:)
for x86_64:
PMD_SIZE = 2^21 = 2M bytes
PUD_SIZE = 2^30 = 1G bytes I mistaken this one for others :(
I also checked ld.hugetlbfs, as you said, only PPC support 16MB huge page.
So it seems 1GB huge page on x86 barely used in real world.
bill
>>
>>
>>> ------------------ Original ------------------
>>> *From: * "bill4carson"<bill4car...@gmail.com>;
>>> *Date: * Mon, Nov 14, 2011 09:47 AM
>>> *To: * "Easley"<ugi...@gmail.com>;
>>> *Cc: * "libhugetlbfs-devel"<libhugetlbfs-devel@lists.sourceforge.net>;
>>> *Subject: * Re: [Libhugetlbfs-devel] How to change the hugepagesize?
>>>
>>>
>>> On 2011年11月10日 17:27, Easley wrote:
>>>> Thank you very much.
>>>> I still have a question. How can I know that have been take effect?
>>>> I take steps as follow:
>>>> ------------------
>>>> mkdir /hugetlb
>>>> mount -t hugetlbfs hugetlbfs /hugetlb
>>>> HUGETLB_MORECORE=yes LD_PRELOAD=libhugetlbfs.so hugepagesz=16M
>>>> hugepages=32 ./myprogram
>>>> ------------------
>>>> That's right?
>>> No
>>>
>>> hugepagesz=16M hugepages=32 is for kernel boot command line
>>>
>>> HUGETLB_MORECORE=yes LD_PRELOAD=libhugetlbfs.so will let malloc get huge
>>> page based memory.
>>>
>>>
>>>
>>>> Easley
>>>> ------------------ Original ------------------
>>>> *From: * "bill4carson"<bill4car...@gmail.com>;
>>>> *Date: * Thu, Nov 10, 2011 11:24 AM
>>>> *To: * "Easley"<ugi...@gmail.com>;
>>>> *Cc: * "libhugetlbfs-devel"<libhugetlbfs-devel@lists.sourceforge.net>;
>>>> *Subject: * Re: [Libhugetlbfs-devel] How to change the hugepagesize?
>>>>
>>>>
>>>> On 2011年11月10日 10:41, Easley wrote:
>>>>> Hi,
>>>>>
>>>>> I run "grep Huge /proc/meminfo" in rhel5.4 .
>>>>> it shows:
>>>>> HugePages_Total: 0
>>>>> HugePages_Free: 0
>>>>> HugePages_Rsvd: 0
>>>>> Hugepagesize: 2048 kB
>>>>>
>>>>> It says hugepagesize is 2M, how can I change the size to 16M?
>>>>> Any help will be appreciated.
>>>>>
>>>>> Easley
>>>> You can *only* do this by adding "hugepagesz=16M hugepages=32" into
>>>> you command line
>>>> to preallocate 32 16M hugepages.
>>>>
>>>> Prerequisite is you hardware support 16M huge page.
>>>>
>>>>>
>>> ------------------------------------------------------------------------------
>>>>> RSA(R) Conference 2012
>>>>> Save $700 by Nov 18
>>>>> Register now
>>>>> http://p.sf.net/sfu/rsa-sfdev2dev1
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Libhugetlbfs-devel mailing list
>>>>> Libhugetlbfs-devel@lists.sourceforge.net
>>>>> https://lists.sourceforge.net/lists/listinfo/libhugetlbfs-devel
>>>> --
>>>> I am a slow learner
>>>> but I will keep trying to fight for my dreams!
>>>>
>>>> --bill
>>>>
>>> --
>>> I am a slow learner
>>> but I will keep trying to fight for my dreams!
>>>
>>> --bill
>>>
>> --
>> I am a slow learner
>> but I will keep trying to fight for my dreams!
>>
>> --bill
>>
>>
>> ------------------------------------------------------------------------------
>> RSA(R) Conference 2012
>> Save $700 by Nov 18
>> Register now
>> http://p.sf.net/sfu/rsa-sfdev2dev1
>> _______________________________________________
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>> Libhugetlbfs-devel@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/libhugetlbfs-devel
--
I am a slow learner
but I will keep trying to fight for my dreams!
--bill
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