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

[Peter Lieven <pl@kamp.de>]

Am 22.10.2014 um 20:29 schrieb Eric Blake:
> 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?

Mistake

>
>
>> +++ 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?
>

Enabled Write Merging is the default since 2009. We do not display
all other defaults as well. But I don't mind.

Peter