On 12/03/2014 07:49 PM, Jens Axboe wrote:
On 12/03/2014 07:42 PM, Jens Axboe wrote:
On 12/03/2014 11:48 AM, Karthick Srinivasachary wrote:
Hi Folks,
I have question. Any feedback appreciated..!
With buffer_compress_percentage, fio writes random data + zeros.
Is there a way to write random data + repeat_pattern (instead of
zero's). Pattern can be any user given pattern.
We can just make it fill with buffer_pattern instead of zeroing. Given
that the pattern is short enough, it should not skew the compression
rate significantly.
OK, did a quick patch and ran a quick test, looks like it's still within
half a percent.
Pull the latest -git, then apply the attached patch. That should do what
you want. Please report back.
Use this -v2 instead, it fixes a crash if you _don't_ set buffer_pattern...
Updated documentation, everything is now in -git. So forget the patch,
just git pull and try it out.
Note the distinction on using refill_buffers=1 or not. If you don't set
this, then each block will be compressible to the extent specified. But
buffers are recycled, so whole device/file ratios might look different.
If you want the compression percentage to apply across all blocks
written, then you set refill_buffers=1 as well.
--
Jens Axboe
--
To unsubscribe from this list: send the line "unsubscribe fio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
