Re: [Qemu-devel] [PATCHv2 3/6] block: add a knob to disable multiwrite_merge

[Eric Blake <eblake@redhat.com>]

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On 10/22/2014 07:21 AM, Peter Lieven wrote:
> The block layer silently merges write requests since
> commit 40b4f539. This patch adds a knob to disable
> this feature as there has been some discussion lately
> if multiwrite is a good idea at all and as it falsifies
> benchmarks.
> 
> Signed-off-by: Peter Lieven <pl@kamp.de>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> 
> Signed-off-by: Peter Lieven <pl@kamp.de>

Is the double s-o-b intentional?


> +++ b/hmp.c
> @@ -348,6 +348,10 @@ void hmp_info_block(Monitor *mon, const QDict *qdict)
>                             BlockdevDetectZeroesOptions_lookup[info->value->inserted->detect_zeroes]);
>          }
>  
> +        if (!info->value->inserted->write_merging) {
> +            monitor_printf(mon, "    Write Merging:    off\n");
> +        }

Is it also worth printing something if write merging is enabled?

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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