[Libguestfs] [Qemu-devel] Effect of qemu-img convert -m and -W options

[Richard W.M. Jones]

On Thu, Nov 16, 2017 at 03:51:29PM +0100, Peter Lieven wrote:
> Afaik all writes to the same QCOW2 serialize because of the s->lock that
> is held during the write. So its not suprising that there is no benefit from
> mutliple threads as long as reading from the RAW file involves no delay.
> Which is likely due to readahead of the OS.

I guess this would explain it, thanks.

Rich.

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