random buffer_compress_percentage instead of static

random buffer_compress_percentage instead of static

[Sunil Vettukalppurathu]

Hi,

Currently we can’t vary % of compressible data from block to block (as
far as I know). The value provided  for buffer_compress_percentage is
used for all blocks.

"""
buffer_compress_percentage=int
If this is set, then fio will attempt to provide I/O buffer content
(on WRITEs) that compresses to the specified
level. Fio does this by providing a mix of random data followed by
fixed pattern data. """

As we have a requirement to test with random compression %, we
modified the code to accept a range of values for
buffer_compress_percentage instead of one number so that the
percentage changes from block to block – random value between min and
max.

Not sure if  it’s useful for others; if so, will send the patch for review.

Thanks,
--Sunil

Re: random buffer_compress_percentage instead of static

[Jens Axboe]

On 6/24/21 12:38 PM, Sunil Vettukalppurathu wrote:
> Hi,
> 
> Currently we can’t vary % of compressible data from block to block (as
> far as I know). The value provided  for buffer_compress_percentage is
> used for all blocks.
> 
> """
> buffer_compress_percentage=int
> If this is set, then fio will attempt to provide I/O buffer content
> (on WRITEs) that compresses to the specified
> level. Fio does this by providing a mix of random data followed by
> fixed pattern data. """
> 
> As we have a requirement to test with random compression %, we
> modified the code to accept a range of values for
> buffer_compress_percentage instead of one number so that the
> percentage changes from block to block – random value between min and
> max.
> 
> Not sure if  it’s useful for others; if so, will send the patch for review.

Please do, sounds like a useful feature. How is it managed in terms of
options?

-- 
Jens Axboe