Add support for zones of random IO, with varying frequency of access
Let's say you want to ensure that 50% of the IO falls in the first 5%
of the flie, with the remaining 50% over the last 95%. Now that's
possible with random_distribution=zoned. For this particular case,
you would do:
random_distribution=zoned:50/5:50/95
Up to 64 ranges can be specified, and multiple data directions can
be given as well. The above would apply to both reads, writes, and
trims. If you wanted to have 50% of the writes fall in the first
10%, 25% in the next 10%, and the last 25% over the remaining 80%,
you could extend the above ala:
random_distribution=zoned:50/5:50/95,50/10:25/10:25/80
Signed-off-by: Jens Axboe <axboe@fb.com>