Re: Possible bug when setting compression

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On 03/14/2014 02:53 PM, Matthew Eaton wrote:
So that wont work as-is, since the parser will bypass the store when the
callback is specified. It needs a one-liner, please try this updated one
instead.

--
Jens Axboe


Ok, so it looks like everything works now except for zero_buffers.

fio-2.1.6.1-11-g0574 + patch

buffer_compress_percentage=100
iops=83457

buffer_compress_percentage=50
iops=78836

buffer_compress_percentage=1
iops=52785

buffer_compress_percentage=0
iops=51013

zero_buffers
iops=69465

scramble_buffers=0
zero_buffers
iops=83451

zero_buffers and buffer_compres_percentage=100 are essentially the same thing, for both cases it writes buffers just fill of zeroes. So I'm not sure what you were expecting here since you don't think it works as it should?

If you have both zero_buffers and scramble set, then the result will be a bit less compressible. The goal of scramble_buffers is to defeat basic dedupe attempts. So even if you don't fully refill your buffers every time, the blocks will be a bit different.

--
Jens Axboe


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