Re: [Qemu-devel] tuning parameters qed

[PANKAJ RAWAT]

Thanks for the reply .
we can change the cluster_size by qemu-img command
but how can we change  L1/L2 table size ?

On Mon, Mar 12, 2012 at 3:17 PM, Stefan Hajnoczi <address@hidden> wrote:

On Mon, Mar 12, 2012 at 9:12 AM, PANKAJ RAWAT <address@hidden> wrote:
> Hi all i have a kvm machine and i use qed format as the disk image format
> I want to improve the I/O performance of my machine
> can anyone tell other then cluster_size and cache what are the tunining
> parameters for qed so that i can improve the performance of my VM ?

Cluster and L1/L2 table size are the only QED-specific parameters.

What to tune really depends on what bottleneck you are seeing.  You
need to do disk I/O benchmarks to find that out.

If you are generally looking for good settings, I suggest leaving the
QED parameters at their default and running with -drive
if=virtio,cache=none,aio=native,file=path/to/image.qed with a recent
QEMU and host kernel.

Stefan

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Pankaj Rawat