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From: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
To: Mark Nelson <mark.nelson@inktank.com>
Cc: Joao Eduardo Luis <joao.luis@inktank.com>,
	"ceph-devel@vger.kernel.org" <ceph-devel@vger.kernel.org>
Subject: Re: less cores more iops / speed
Date: Thu, 08 Nov 2012 16:14:32 +0100	[thread overview]
Message-ID: <509BCC58.3070003@profihost.ag> (raw)
In-Reply-To: <509BB156.5080404@inktank.com>

Am 08.11.2012 14:19, schrieb Mark Nelson:
> On 11/08/2012 02:45 AM, Stefan Priebe - Profihost AG wrote:
>> Am 08.11.2012 01:59, schrieb Mark Nelson:
>>> There's also the context switching overhead.  It'd be interesting to
>>> know how much the writer processes were shifting around on cores.
>> What do you mean by that? I'm talking about the KVM guest not about the
>> ceph nodes.
>
> in this case, is fio bouncing around between cores?

Thanks you're correct. If i bind fio to two cores on a 8 core VM it runs 
with 16.000 iops.

So it is a problem of KVM which let's the processes jump between cores a 
lot.

Greets,
Stefan

  reply	other threads:[~2012-11-08 15:14 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-07 22:02 less cores more iops / speed Stefan Priebe
2012-11-08  0:00 ` Joao Eduardo Luis
2012-11-08  0:16   ` Openstack - Boot From New Volume Quenten Grasso
2012-11-08  0:59   ` less cores more iops / speed Mark Nelson
2012-11-08  8:45     ` Stefan Priebe - Profihost AG
2012-11-08  8:58       ` Alexandre DERUMIER
2012-11-08  9:02         ` Stefan Priebe - Profihost AG
2012-11-08  9:05           ` Alexandre DERUMIER
2012-11-08  9:28             ` Stefan Priebe - Profihost AG
2012-11-08 13:19       ` Mark Nelson
2012-11-08 15:14         ` Stefan Priebe - Profihost AG [this message]
2012-11-08 15:53           ` Alexandre DERUMIER
2012-11-08 21:52             ` Andrey Korolyov
2012-11-09  8:43             ` Stefan Priebe - Profihost AG
2012-11-08  0:59   ` Mark Nelson
2012-11-08  5:42 ` Dietmar Maurer
2012-11-08  5:49   ` Dietmar Maurer
2012-11-08  6:20     ` Stefan Priebe - Profihost AG
2012-11-08  5:49   ` Stefan Priebe - Profihost AG
2012-11-08  5:54     ` Dietmar Maurer
2012-11-08  6:21       ` Stefan Priebe - Profihost AG
  -- strict thread matches above, loose matches on Subject: below --
2012-11-12 15:33 [pve-devel] " Stefan Priebe - Profihost AG
     [not found] ` <50A116DC.2020509-2Lf/h1ldwEHR5kwTpVNS9A@public.gmane.org>
2012-11-12 15:39   ` Alexandre DERUMIER

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