[pve-devel] qemu-server:add support for hugetlbfs

[Cesar Peschiera]

Yes i will do the test for MS-SQL-Server 2008 STD with and without THP
(Transparent Huge Pages) in a VM with 243 GB RAM (without KSM and Balloon
enabled) as soon as i have solved my problem of quorum, and i will
communicate the results.

Moreover, i guess that the best choice is that you can enable or disable
static hugepage for each VM, that in my case with MS-SQL, i guess that will
be better have it disabled, and i will be communicating it.

Moreover, to short term, with some extra HDDs in one of these servers, i 
believe that i can do tests as help for the future versions of PVE if you 
believe to will find it useful (always that the proprietary of these Dell 
servers also be agree, that as he has PVE, i guess that he also will be 
interested).

----- Original Message ----- 
From: "Alexandre DERUMIER" <aderumier at odiso.com>
To: "dietmar" <dietmar at proxmox.com>
Cc: "pve-devel" <pve-devel at pve.proxmox.com>
Sent: Sunday, December 21, 2014 9:23 AM
Subject: Re: [pve-devel] qemu-server:add support for hugetlbfs


>>>1.) Is there some edivence that it is faster (under realistic workload)?
>
> I known that transparent hugepage can be really a problem with a lot of
> database (oracle,mysql,redis,..)
> I never bench it myself, but I hope that Cesar will do it ;).
>
> Disable transparent hugepage is a solution, but it's disable it for all
> the vms.
>
> I think that static hugepage can do the job, but it need to be tested.
>
>
>>>2.) Where do we free/dealloc those hugepages? Are the associated with the
>>>KVM
>>>process somehow?
>
> I'm not sure that when hupage are defined, they use memory by default.
>
> But when the kvm process is starting, the memory is allocated/reserverd
> for the kvm process,
> and the memory is free up on kvm process stop.
>
>
> ----- Mail original -----
> De: "dietmar" <dietmar at proxmox.com>
> À: "aderumier" <aderumier at odiso.com>, "pve-devel"
> <pve-devel at pve.proxmox.com>
> Envoyé: Samedi 20 Décembre 2014 09:32:42
> Objet: Re: [pve-devel] qemu-server:add support for hugetlbfs
>
>> This add support for manually defined hugepages,
>> which can be faster than transparent hugepages for some workload like
>> databases
>
> 1.) Is there some edivence that it is faster (under realistic workload)?
>
> 2.) Where do we free/dealloc those hugepages? Are the associated with the
> KVM
> process somehow?
>
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