From: Stefan Hajnoczi <stefanha@gmail.com>
To: David Marchand <david.marchand@6wind.com>
Cc: Henning Schild <henning.schild@siemens.com>,
Olivier MATZ <olivier.matz@6wind.com>, kvm <kvm@vger.kernel.org>,
qemu-devel <qemu-devel@nongnu.org>,
Linux Virtualization <virtualization@lists.linux-foundation.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Vincent JARDIN <vincent.jardin@6wind.com>,
"thomas.monjalon@6wind.com" <thomas.monjalon@6wind.com>
Subject: Re: [Qemu-devel] Why I advise against using ivshmem
Date: Wed, 18 Jun 2014 18:51:20 +0800 [thread overview]
Message-ID: <20140618105120.GI14030@stefanha-thinkpad.redhat.com> (raw)
In-Reply-To: <53A00464.8090609@6wind.com>
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On Tue, Jun 17, 2014 at 11:03:32AM +0200, David Marchand wrote:
> On 06/17/2014 04:54 AM, Stefan Hajnoczi wrote:
> >ivshmem has a performance disadvantage for guest-to-host
> >communication. Since the shared memory is exposed as PCI BARs, the
> >guest has to memcpy into the shared memory.
> >
> >vhost-user can access guest memory directly and avoid the copy inside the guest.
>
> Actually, you can avoid this memory copy using frameworks like DPDK.
I guess it's careful to allocate all packets in the mmapped BAR?
That's fine if you can modify applications but doesn't work for
unmodified applications using regular networking APIs.
Stefan
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WARNING: multiple messages have this Message-ID (diff)
From: Stefan Hajnoczi <stefanha@gmail.com>
To: David Marchand <david.marchand@6wind.com>
Cc: Henning Schild <henning.schild@siemens.com>,
Olivier MATZ <olivier.matz@6wind.com>, kvm <kvm@vger.kernel.org>,
qemu-devel <qemu-devel@nongnu.org>,
Linux Virtualization <virtualization@lists.linux-foundation.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Vincent JARDIN <vincent.jardin@6wind.com>,
"thomas.monjalon@6wind.com" <thomas.monjalon@6wind.com>
Subject: Re: [Qemu-devel] Why I advise against using ivshmem
Date: Wed, 18 Jun 2014 18:51:20 +0800 [thread overview]
Message-ID: <20140618105120.GI14030@stefanha-thinkpad.redhat.com> (raw)
In-Reply-To: <53A00464.8090609@6wind.com>
[-- Attachment #1: Type: text/plain, Size: 663 bytes --]
On Tue, Jun 17, 2014 at 11:03:32AM +0200, David Marchand wrote:
> On 06/17/2014 04:54 AM, Stefan Hajnoczi wrote:
> >ivshmem has a performance disadvantage for guest-to-host
> >communication. Since the shared memory is exposed as PCI BARs, the
> >guest has to memcpy into the shared memory.
> >
> >vhost-user can access guest memory directly and avoid the copy inside the guest.
>
> Actually, you can avoid this memory copy using frameworks like DPDK.
I guess it's careful to allocate all packets in the mmapped BAR?
That's fine if you can modify applications but doesn't work for
unmodified applications using regular networking APIs.
Stefan
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next prev parent reply other threads:[~2014-06-18 10:51 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-10 16:48 Using virtio for inter-VM communication Henning Schild
2014-06-10 16:48 ` [Qemu-devel] " Henning Schild
2014-06-10 22:15 ` Vincent JARDIN
2014-06-10 22:15 ` Vincent JARDIN
2014-06-10 22:15 ` [Qemu-devel] " Vincent JARDIN
2014-06-12 6:48 ` Markus Armbruster
2014-06-12 6:48 ` Markus Armbruster
2014-06-12 6:48 ` [Qemu-devel] " Markus Armbruster
2014-06-12 7:44 ` Henning Schild
2014-06-12 7:44 ` [Qemu-devel] " Henning Schild
2014-06-12 9:31 ` Vincent JARDIN
2014-06-12 9:31 ` Vincent JARDIN
2014-06-12 9:31 ` [Qemu-devel] " Vincent JARDIN
2014-06-12 12:55 ` Markus Armbruster
2014-06-12 14:40 ` Why I advise against using ivshmem (was: [Qemu-devel] Using virtio for inter-VM communication) Markus Armbruster
2014-06-12 14:40 ` Markus Armbruster
2014-06-12 14:40 ` [Qemu-devel] Why I advise against using ivshmem (was: " Markus Armbruster
2014-06-12 16:02 ` Why I advise against using ivshmem Vincent JARDIN
2014-06-12 16:02 ` [Qemu-devel] " Vincent JARDIN
2014-06-12 16:54 ` Paolo Bonzini
2014-06-12 16:54 ` [Qemu-devel] " Paolo Bonzini
2014-06-13 8:46 ` Markus Armbruster
2014-06-13 9:26 ` Vincent JARDIN
2014-06-13 9:31 ` Jobin Raju George
2014-06-13 9:31 ` Jobin Raju George
2014-06-13 9:31 ` Jobin Raju George
2014-06-13 9:48 ` Olivier MATZ
2014-06-13 9:48 ` Olivier MATZ
2014-06-13 9:48 ` Olivier MATZ
2014-06-13 10:09 ` Paolo Bonzini
2014-06-13 13:41 ` Vincent JARDIN
2014-06-13 13:41 ` Vincent JARDIN
2014-06-13 13:41 ` Vincent JARDIN
2014-06-13 14:10 ` Paolo Bonzini
2014-06-13 14:10 ` Paolo Bonzini
2014-06-14 18:01 ` Vincent JARDIN
2014-06-14 18:01 ` Vincent JARDIN
2014-06-17 2:54 ` Stefan Hajnoczi
2014-06-17 9:03 ` David Marchand
2014-06-17 9:03 ` David Marchand
2014-06-17 9:44 ` Paolo Bonzini
2014-06-18 10:48 ` Stefan Hajnoczi
2014-06-18 10:48 ` Stefan Hajnoczi
2014-06-18 14:57 ` David Marchand
2014-06-18 14:57 ` David Marchand
2014-06-18 14:57 ` David Marchand
2014-06-18 15:10 ` Paolo Bonzini
2014-06-21 9:34 ` Stefan Hajnoczi
2014-06-26 20:02 ` Cam Macdonell
2014-06-26 20:02 ` Cam Macdonell
2014-06-18 15:01 ` Andreas Färber
2014-06-18 15:01 ` Andreas Färber
2014-06-19 8:25 ` David Marchand
2014-06-19 8:25 ` David Marchand
2014-06-19 8:25 ` David Marchand
2014-06-18 15:01 ` Andreas Färber
2014-06-30 11:10 ` Markus Armbruster
2014-06-30 11:10 ` Markus Armbruster
2014-06-30 11:10 ` Markus Armbruster
2014-06-18 10:51 ` Stefan Hajnoczi [this message]
2014-06-18 10:51 ` Stefan Hajnoczi
2014-06-18 14:58 ` David Marchand
2014-06-18 14:58 ` David Marchand
2014-06-18 14:58 ` David Marchand
2014-06-18 14:22 ` Claudio Fontana
2014-06-17 9:03 ` David Marchand
2014-06-13 9:29 ` Jobin Raju George
2014-06-13 9:29 ` [Qemu-devel] " Jobin Raju George
2014-06-13 9:29 ` Jobin Raju George
2014-06-12 16:02 ` Vincent JARDIN
2014-06-12 2:27 ` Using virtio for inter-VM communication Rusty Russell
2014-06-12 2:27 ` Rusty Russell
2014-06-12 2:27 ` [Qemu-devel] " Rusty Russell
2014-06-12 5:32 ` Jan Kiszka
2014-06-12 5:32 ` [Qemu-devel] " Jan Kiszka
2014-06-13 0:47 ` Rusty Russell
2014-06-13 0:47 ` [Qemu-devel] " Rusty Russell
2014-06-13 6:23 ` Jan Kiszka
2014-06-13 6:23 ` [Qemu-devel] " Jan Kiszka
2014-06-13 8:45 ` Paolo Bonzini
2014-06-13 8:45 ` [Qemu-devel] " Paolo Bonzini
2014-06-15 6:20 ` Jan Kiszka
2014-06-15 6:20 ` Jan Kiszka
2014-06-15 6:20 ` [Qemu-devel] " Jan Kiszka
2014-06-17 5:24 ` Paolo Bonzini
2014-06-17 5:24 ` [Qemu-devel] " Paolo Bonzini
2014-06-17 5:57 ` Jan Kiszka
2014-06-17 5:57 ` Jan Kiszka
2014-06-17 5:57 ` [Qemu-devel] " Jan Kiszka
2014-06-17 5:24 ` Paolo Bonzini
2014-06-12 5:32 ` Jan Kiszka
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