[pve-devel] less cores more iops / speed

[Stefan Priebe - Profihost AG]

Am 09.11.2012 11:10, schrieb Alexandre DERUMIER:
>>> Doesn't make any difference. But i'm now at 18.000 iops ;-)
>
> Read and writes ?  do you have found your write cpu problem ?

Yes. CPU Load in Ceph for rand. 4k writes can be dropped by 50% when 
disabling all debug setting (see my last post on ceph mailinglist).

Stefan

> ----- Mail original -----
>
> De: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag>
> À: "Alexandre DERUMIER" <aderumier at odiso.com>
> Cc: pve-devel at pve.proxmox.com, "Dietmar Maurer" <dietmar at proxmox.com>
> Envoyé: Vendredi 9 Novembre 2012 11:08:18
> Objet: Re: [pve-devel] less cores more iops / speed
>
> Am 09.11.2012 11:01, schrieb Alexandre DERUMIER:
>> do you have tried fio with --numjobs option ? (I'll make more fio threads I think, maybe set it to the number of cpu you have)
>
> Doesn't make any difference. But i'm now at 18.000 iops ;-)
>
>> ----- Mail original -----
>>
>> De: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag>
>> À: "Dietmar Maurer" <dietmar at proxmox.com>
>> Cc: "Alexandre DERUMIER" <aderumier at odiso.com>, pve-devel at pve.proxmox.com
>> Envoyé: Vendredi 9 Novembre 2012 10:06:45
>> Objet: Re: [pve-devel] less cores more iops / speed
>>
>> I'm pinnin inside the kvm process the fio process. SO it shouldn't be a
>> problem of librbd alone.
>>
>> Stefan
>> Am 09.11.2012 09:59, schrieb Dietmar Maurer:
>>>> Am 09.11.2012 09:50, schrieb Dietmar Maurer:
>>>>>>> It's try to keep process on same numa node and I think it's also
>>>>>>> doing some
>>>>>> dynamic pinning.
>>>>>>
>>>>>> numad doesn't help but libvirt seems to support pinning of kvm instances.
>>>>>> Maybe pve should support pinning too?
>>>>>
>>>>> So far I never had such problems.
>>>>>
>>>>> IMHO, Manual pinning is the wrong way.
>>>>
>>>> But doing heavy I/O with 8 Cores is much slower than with 2 Cores that can't
>>>> be correct...
>>>
>>> What exactly is the suggestion? So far only rbd client shows such behavior?
>>>