iodepth_batch default 1 or iodepth

iodepth_batch default 1 or iodepth

[Elliott, Robert (Server Storage)]

fio.1 says the default value for iodepth_batch is iodepth, but HOWTO says it defaults to 1 and options.c defaults to 1.  Which is intended?  

The value is not displayed in the fio output anywhere, so it's unclear what you're getting unless you specify a value.

fio.1:
       iodepth_batch=int
              Number of I/Os to submit at once.  Default: iodepth.

HOWTO:
iodepth_batch_submit=int
iodepth_batch=int This defines how many pieces of IO to submit at once.
                It defaults to 1 which means that we submit each IO
                as soon as it is available, but can be raised to submit
                bigger batches of IO at the time.

options.c:
        {
                .name   = "iodepth_batch_complete",
                .lname  = "IO Depth batch complete",
                .type   = FIO_OPT_INT,
                .off1   = td_var_offset(iodepth_batch_complete),
                .help   = "Number of IO buffers to retrieve in one go",
                .parent = "iodepth",
                .hide   = 1,
                .minval = 0,
                .interval = 1,
                .def    = "1",
                .category = FIO_OPT_C_IO,
                .group  = FIO_OPT_G_IO_BASIC,
        },

---
Rob Elliott    HP Server Storage

Re: iodepth_batch default 1 or iodepth

[Jens Axboe]

On 2014-02-25 12:45, Elliott, Robert (Server Storage) wrote:
> fio.1 says the default value for iodepth_batch is iodepth, but HOWTO says it
 > defaults to 1 and options.c defaults to 1.  Which is intended?
>
> The value is not displayed in the fio output anywhere, so it's unclear
 > what you're getting unless you specify a value.

The documentation is wrong (and illogical), it should default to 1 if 
not given. Which it does. So we should probably just fix up the 
documentation.

-- 
Jens Axboe