On 09/26/2014 01:08 PM, Jens Axboe wrote:
> On 09/26/2014 12:30 PM, Alket Memushaj wrote:
>> Hi,
>>
>> I am playing with the dedupe option and while it works well under
>> synthetic tests, it doesn't seem to work when replaying a trace.
>>
>> My test jobs are simple:
>>
>> fio --name=replay --ioengine=libaio --direct=1 --iodepth=32
>> --read_iolog=/path/to/trace --dedupe_percentage=80
> 
> That should work, as far as I can tell, since we do the buffer fill
> after the iolog retrieval has filled out an IO unit for us. Can you say
> more about what doesn't appear to work?
> 
>> I understand that block sizes would be variable during a trace replay,
>> but is it possible to specify a base block size and calculate dedupe
>> based on that for blocks that are multiples of the base size?
> 
> Ah, that might be the key element here. Yes, the dedupe part might not
> really work well for multiple write sizes. Nothing that inherently
> prevents that from working, just didn't add that bit yet. Will do that.

Does it work better with this patch?

-- 
Jens Axboe