Re: [Qemu-devel] Improving QEMU memcpy performance

[Stefan Hajnoczi]

On Tue, Mar 8, 2011 at 5:52 AM, Gunasekaran Dharman <address@hidden> wrote:
> Iam using QEMU emulated ARM Realview board with Linux as guest OS for my
> application development. This virtual machine is running on x86 Linux host.
> My application is facing performance issue as memcpy in guest machine is
> taking lot of time compared to the same memcpy in host machine.
> To improve the performance, Iam planning to add new device (Virtual DMA) in
> QEMU which will implement memcpy operation in host for guest application.
> The memcpy function in guest will be replaced with ioctl to instruct the
> Virtual DMA to do memcpy in host for the guest application.
> Iam planning to work on this. As Iam new to QEMU, before starting the work,
> I would like to know whether this is a possibility.
> Will there be any problem in accessing guest buffer addresses in QEMU? Is
> this approach right?
> Please let me know your views about this.

The same effort could be spent on improving TCG performance in your
ARM -> x86 case.  That might make other non-memcpy code faster too.

Stefan