Another idiosyncrasy that I observed was, With rw=write, compression options are not heeded. They seem to work only rw=rw. Thanks, Srinath On Thu, Jun 30, 2016 at 10:58 AM, Srinath Krishna Ananthakrishnan <ska@xxxxxxxxx> wrote: > I don't want fio to vary the data and need it to be more deterministic. > > After playing with it for quite some time, I have the following > (inconclusive) theory. > > 1. If no verify options are set, fio generates > buffer_compress_percentage worth of compressible data per block size. > Compressible data is always zeroed out. > 2. With verify options, fio generates buffer_compress_percentage worth > of compressible data (zeroes) for some blocks but there are these > bunch of blocks from time to time that contain purely random data. > > From the manual, verify options add additional meta data to the header > of every block for verification but I'm not sure why some blocks turn > out to be completely random with this setting on. I tried multiple > verify hashes with the same result. > > With either of the cases, I don't seem to get the buffer_pattern > setting working. > > > Thanks, > Srinath > > > On Mon, Jun 27, 2016 at 10:16 PM, Sitsofe Wheeler <sitsofe@xxxxxxxxx> wrote: >> On 27 June 2016 at 21:41, Srinath Krishna Ananthakrishnan <ska@xxxxxxxxx> wrote: >>> >>> [small_write] >>> rw=rw >>> blocksize=4k >>> size=100M >>> verify=crc32c-intel >>> buffer_compress_percentage=50 >>> buffer_pattern="abcd" >>> >>> With this, I don't see fio generating compressible data with the >>> pattern and still reverts to generating random data. Anything I'm >>> missing? >> >> You're forcing the pattern of data that must be used via >> buffer_pattern so you aren't you taking away the ability for fio to >> vary the data? Do you get a different result if you don't specify >> buffer_pattern ? >> >> -- >> Sitsofe | http://sucs.org/~sits/ -- 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
