[PVE-User] THP

[Alexandre DERUMIER]

>>What is big memory in this context? how many GB?

default page are 4k , THP are 2MB.

If you need to access 2MB memory, with 4K pages, you need to do 512calls. with THP only 1 call.

That's why it's faster.

The more memory the vm need to address , the more benefit you'll have.
You can enable it by default if you want.

The only problem with THP, is that some workload are not happy with it, because THP need to defragment pages sometime.


They are also a new option in proxmox , since last month : static hugepages.

you can add:

hugepages : 2|1024

to force 2mb hugepage or 1GB hugepages for this specific vm.

(Note that in this case, the memory is reserved. So, no fragmentation can occur, but KSM is not working with this memory area)


----- Mail original -----
De: "Gilberto Nunes" <gilberto.nunes32 at gmail.com>
À: "proxmoxve" <pve-user at pve.proxmox.com>
Envoyé: Vendredi 15 Juillet 2016 14:27:37
Objet: Re: [PVE-User] THP

Hi 

I think Alexandre means big huge page memory... Some databases, like SQL 
and Oracle, when have big tables, views, whatever, tend to use big page 
memory in the file system. 



2016-07-15 9:22 GMT-03:00 Lindsay Mathieson <lindsay.mathieson at gmail.com>: 

> On 15/07/2016 9:48 PM, Alexandre DERUMIER wrote: 
> 
>> It should improve performance for vms with big memory (like database for 
>> example) 
>> 
> 
> 
> 
> What is big memory in this context? how many GB? 
> 
> -- 
> Lindsay Mathieson 
> 
> 
> _______________________________________________ 
> pve-user mailing list 
> pve-user at pve.proxmox.com 
> http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user 
> 



-- 

Gilberto Ferreira 
+55 (47) 9676-7530 
Skype: gilberto.nunes36 
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