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From: Jan Kiszka <jan.kiszka@web.de>
To: Dietmar Maurer <dietmar@proxmox.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
	Peter Lieven <lieven-lists@dlhnet.de>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores
Date: Thu, 08 Nov 2012 10:39:16 +0100	[thread overview]
Message-ID: <509B7DC4.3010802@web.de> (raw)
In-Reply-To: <24E144B8C0207547AD09C467A8259F75577EC4B2@lisa.maurer-it.com>

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On 2012-11-06 12:24, Dietmar Maurer wrote:
>> On 2012-11-06 10:46, Dietmar Maurer wrote:
>>>>> This obviously breaks vhost when using multiple cores.
>>>>
>>>> With "obviously" you mean you already have a clue why?
>>>>
>>>> I'll try to reproduce.
>>>
>>> No, sorry - just meant the performance regression is obvious (factor 20 to
>> 40).
>>>
>>
>> OK. Did you try to bisect over qemu-kvm as well?
> 
> No (I thought that is the same code base?)

Already answered, though accidentally in private only: it is the same
code base now, but qemu-kvm has a different history and may contain
versions that didn't suffer from the issue.

Meanwhile I quickly tried to reproduce but didn't succeed so far
(>10GBit between host and guest with vhost=on and 2 guest cores).
However, I finally realized that we are talking about a pretty special
host kernel which I don't have around. I guess this is better dealt with
by Red Hat folks. Specifically, they should know what features that
kernel exposes and what it lacks.

Jan


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  reply	other threads:[~2012-11-08  9:39 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-05 11:51 [Qemu-devel] slow virtio network with vhost=on and multiple cores Dietmar Maurer
2012-11-05 12:36 ` Stefan Hajnoczi
2012-11-05 15:01   ` Dietmar Maurer
2012-11-06  6:12   ` Dietmar Maurer
2012-11-06  7:46     ` Peter Lieven
2012-11-06  7:51       ` Dietmar Maurer
2012-11-06  9:01       ` Dietmar Maurer
2012-11-06  9:26         ` Jan Kiszka
2012-11-06  9:46           ` Dietmar Maurer
2012-11-06 10:12             ` Jan Kiszka
2012-11-06 11:24               ` Dietmar Maurer
2012-11-08  9:39                 ` Jan Kiszka [this message]
2012-11-08 10:55                   ` Peter Lieven
2012-11-08 12:03                   ` Dietmar Maurer
2012-11-08 15:02                     ` Peter Lieven
2012-11-09  5:55                       ` Dietmar Maurer
2012-11-09 17:27                         ` Peter Lieven
2012-11-09 17:51                           ` Peter Lieven
2012-11-09 18:03                             ` Peter Lieven
2012-11-13 11:44                               ` Peter Lieven
2012-11-13 11:49                               ` Peter Lieven
2012-11-13 16:22                                 ` Michael S. Tsirkin
2012-11-13 16:21                                   ` Peter Lieven
2012-11-13 16:26                                     ` Michael S. Tsirkin
2012-11-13 16:27                                       ` Peter Lieven
2012-11-13 16:59                                         ` Dietmar Maurer
2012-11-13 17:03                                         ` Michael S. Tsirkin
2012-11-13 16:33                                   ` Michael S. Tsirkin
2012-11-13 16:35                                     ` Peter Lieven
2012-11-13 16:46                                       ` Michael S. Tsirkin
2012-11-13 17:03                                     ` Dietmar Maurer
2012-11-13 17:07                                       ` Michael S. Tsirkin
2012-11-13 17:38                                         ` Dietmar Maurer
2012-11-15 18:26                                           ` Peter Lieven
2012-11-16 10:44                                             ` Dietmar Maurer
2012-11-16 11:00                                               ` Alexandre DERUMIER
2012-12-03 11:23                                                 ` Peter Lieven
2012-12-09 18:38                                                   ` Alexandre DERUMIER
2013-03-14  9:22                                                     ` Davide Guerri
2013-03-14 10:43                                                       ` Alexandre DERUMIER
2013-03-14 17:50                                                         ` Michael S. Tsirkin
2013-03-14 18:15                                                           ` Davide Guerri
2013-03-14 18:21                                                             ` Peter Lieven
2013-03-14 23:04                                                               ` Davide Guerri
2013-03-15  7:23                                                                 ` Peter Lieven
2013-03-17  9:08                                                                   ` Michael S. Tsirkin
2013-03-18  9:50                                                                     ` Alexandre DERUMIER
2013-03-18  9:53                                                                       ` Michael S. Tsirkin
2013-03-25 13:34                                                                         ` Peter Lieven
2012-11-19 13:49                                     ` Peter Lieven
2012-11-06  6:48   ` Dietmar Maurer

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