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Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores |
Date: |
Tue, 13 Nov 2012 18:33:32 +0200 |
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
> > >>...
> > >>
> > >>
> > >
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, (continued)
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/09
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/09
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/09
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Michael S. Tsirkin, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Michael S. Tsirkin, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Dietmar Maurer, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Michael S. Tsirkin, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores,
Michael S. Tsirkin <=
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Michael S. Tsirkin, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Dietmar Maurer, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Michael S. Tsirkin, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Dietmar Maurer, 2012/11/13
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/15
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Dietmar Maurer, 2012/11/16
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Alexandre DERUMIER, 2012/11/16
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/19
- Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores, Peter Lieven, 2012/11/13