Hi Jens Axboe & Sitsofe Wheeler Thank you very much for your help. get_io_u finally call fill_io_buffer to fill the buffer, function fill_io_buffer uses td->buf_state and td->buf_state_prev to generate duplicated data if the dedupe_percentage is set. populate_verify_io_u finally call fill_random_buf_percentage to fill the buffer, it use td->verify_state to generate random data. Should I create a issue on https://github.com/axboe/fio/issues? At 2018-10-18 03:05:33, "Jens Axboe" <axboe@xxxxxxxxx> wrote: >On 10/17/18 12:32 PM, Sitsofe Wheeler wrote: >> On Wed, 17 Oct 2018 at 13:31, Changyu <feng_changyu@xxxxxxx> wrote: >>> >>> Hi, >>> >>> I set "dedupe_percentage " to let FIO generate some duplicated data. I also want read these data back and verify it. >>> But, there is no duplicated data after setting "verify" parameter. >>> >>> checking the source code, I found that function do_io in file backend.c fill the buffer twice. the source code is as below. >>> >>> do_io() >>> { >>> io_u = get_io_u(td); >>> ..... >>> if (io_u->ddir == DDIR_WRITE && td->flags & TD_F_DO_VERIFY) >>> populate_verify_io_u(td, io_u); >>> } >>> >>> In function get_io_u, the buffer is filled with data as the "dedupe_percentage " specified. >>> In function populate_verify_io_u, the buffer is refilled with random data. So, there would be no duplicated data. >>> >>> Is this a bug? >> >> If it's not (and I'd say it is) then the current behaviour needs to it >> needs to print a "conflicting options" error rather than silently not >> doing what was asked. Someone else has reported something similar over >> on https://github.com/axboe/fio/issues/449 ... > >They should definitely be using the same fill methods. > >-- >Jens Axboe
