From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
rusty@rustcorp.com.au, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org, avi@redhat.com,
Anthony Liguori <aliguori@us.ibm.com>
Subject: Re: [Qemu-devel] [PATCHv2] virtio-pci: add MMIO property
Date: Tue, 20 Mar 2012 16:32:23 +0000 [thread overview]
Message-ID: <201203201632.23939.paul@codesourcery.com> (raw)
In-Reply-To: <20120319203721.GA9399@redhat.com>
> @@ -682,10 +733,18 @@ void virtio_init_pci(VirtIOPCIProxy *proxy,
> VirtIODevice *vdev) if (size & (size-1))
> size = 1 << qemu_fls(size);
>
> + proxy->bar0_mask = size - 1;
You'll get better performance if you use page-sized mappings. You're already
creating a mapping bigger than the actual data (rounding up to power-of-two),
so you may as well pick a value that's convenient for qemu to map into the
address space.
Paul
WARNING: multiple messages have this Message-ID (diff)
From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Anthony Liguori <aliguori@us.ibm.com>,
kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
rusty@rustcorp.com.au, virtualization@lists.linux-foundation.org,
avi@redhat.com
Subject: Re: [Qemu-devel] [PATCHv2] virtio-pci: add MMIO property
Date: Tue, 20 Mar 2012 16:32:23 +0000 [thread overview]
Message-ID: <201203201632.23939.paul@codesourcery.com> (raw)
In-Reply-To: <20120319203721.GA9399@redhat.com>
> @@ -682,10 +733,18 @@ void virtio_init_pci(VirtIOPCIProxy *proxy,
> VirtIODevice *vdev) if (size & (size-1))
> size = 1 << qemu_fls(size);
>
> + proxy->bar0_mask = size - 1;
You'll get better performance if you use page-sized mappings. You're already
creating a mapping bigger than the actual data (rounding up to power-of-two),
so you may as well pick a value that's convenient for qemu to map into the
address space.
Paul
next prev parent reply other threads:[~2012-03-20 16:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-19 20:37 [PATCHv2] virtio-pci: add MMIO property Michael S. Tsirkin
2012-03-19 20:37 ` [Qemu-devel] " Michael S. Tsirkin
2012-03-20 16:32 ` Paul Brook
2012-03-20 16:32 ` Paul Brook [this message]
2012-03-20 16:32 ` Paul Brook
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