From: "Michael S. Tsirkin" <mst@redhat.com>
To: Peter Lieven <pl@dlhnet.de>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
Peter Lieven <lieven-lists@dlhnet.de>,
Jan Kiszka <jan.kiszka@web.de>,
Dietmar Maurer <dietmar@proxmox.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores
Date: Tue, 13 Nov 2012 18:33:32 +0200 [thread overview]
Message-ID: <20121113163331.GA645@redhat.com> (raw)
In-Reply-To: <20121113162256.GA554@redhat.com>
On Tue, Nov 13, 2012 at 06:22:56PM +0200, Michael S. Tsirkin wrote:
> On Tue, Nov 13, 2012 at 12:49:03PM +0100, Peter Lieven wrote:
> >
> > On 09.11.2012 19:03, Peter Lieven wrote:
> > >Remark:
> > >If i disable interrupts on CPU1-3 for virtio the performance is ok again.
> > >
> > >Now we need someone with deeper knowledge of the in-kernel irqchip and the
> > >virtio/vhost driver development to say if this is a regression in qemu-kvm
> > >or a problem with the old virtio drivers if they receive the interrupt on
> > >different CPUs.
> > anyone?
>
> Looks like the problem is not in the guest: I tried ubuntu guest
> on a rhel host, I got 8GB/s with vhost and 4GB/s without
> on a host to guest banchmark.
>
Tried with upstream qemu on rhel kernel and that's even a bit faster.
So it's ubuntu kernel. vanilla 2.6.32 didn't have vhost at all
so maybe their vhost backport is broken insome way.
>
> >
> > >
> > >Peter Lieven wrote:
> > >>it seems that with in-kernel irqchip the interrupts are distributed across
> > >>all vpcus. without in-kernel irqchip all interrupts are on cpu0. maybe
> > >>this is related.
> > >>
> > >>without inkernel irqchip
> > >> CPU0 CPU1 CPU2 CPU3
> > >> 0: 16 0 0 0 IO-APIC-edge timer
> > >> 1: 23 0 0 0 IO-APIC-edge i8042
> > >> 4: 1 0 0 0 IO-APIC-edge
> > >> 6: 4 0 0 0 IO-APIC-edge
> > >>floppy
> > >> 7: 0 0 0 0 IO-APIC-edge
> > >>parport0
> > >> 8: 0 0 0 0 IO-APIC-edge rtc0
> > >> 9: 0 0 0 0 IO-APIC-fasteoi acpi
> > >> 11: 76 0 0 0 IO-APIC-fasteoi
> > >>uhci_hcd:usb1
> > >> 12: 102 0 0 0 IO-APIC-edge i8042
> > >> 14: 0 0 0 0 IO-APIC-edge
> > >>ata_piix
> > >> 15: 16881 0 0 0 IO-APIC-edge
> > >>ata_piix
> > >> 24: 0 0 0 0 PCI-MSI-edge
> > >>virtio1-config
> > >> 25: 5225 0 0 0 PCI-MSI-edge
> > >>virtio1-requests
> > >> 26: 0 0 0 0 PCI-MSI-edge
> > >>virtio0-config
> > >> 27: 72493 0 0 0 PCI-MSI-edge
> > >>virtio0-input
> > >>...
> > >>
> > >>with inkernel irqchip
> > >> CPU0 CPU1 CPU2 CPU3
> > >> 0: 16 0 0 0 IO-APIC-edge timer
> > >> 1: 0 3 3 1 IO-APIC-edge i8042
> > >> 4: 0 0 1 0 IO-APIC-edge
> > >> 6: 1 0 1 2 IO-APIC-edge
> > >>floppy
> > >> 7: 0 0 0 0 IO-APIC-edge
> > >>parport0
> > >> 8: 0 0 0 0 IO-APIC-edge rtc0
> > >> 9: 0 0 0 0 IO-APIC-fasteoi acpi
> > >> 11: 7 9 4 1 IO-APIC-fasteoi
> > >>uhci_hcd:usb1
> > >> 12: 30 27 29 34 IO-APIC-edge i8042
> > >> 14: 0 0 0 0 IO-APIC-edge
> > >>ata_piix
> > >> 15: 943 937 950 943 IO-APIC-edge
> > >>ata_piix
> > >> 24: 0 0 0 0 PCI-MSI-edge
> > >>virtio0-config
> > >> 25: 930 978 980 947 PCI-MSI-edge
> > >>virtio0-input
> > >> 26: 0 0 1 0 PCI-MSI-edge
> > >>virtio0-output
> > >> 27: 0 0 0 0 PCI-MSI-edge
> > >>virtio1-config
> > >> 28: 543 541 542 553 PCI-MSI-edge
> > >>virtio1-requests
> > >>...
> > >>
> > >>
> > >
next prev parent reply other threads:[~2012-11-13 16:31 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
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 [this message]
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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