Hello there,
If running fio with --create_serialize=1 and --numjobs=2
->setup() callback will be called for each thread,
before the ->init() callback is called for each thread:
my_fio_setup: td: 0x7eff72d6a000
my_fio_setup: td: 0x7eff72daea70
my_fio_init: td: 0x7eff72d6a000
my_fio_init: td: 0x7eff72daea70
However, if running fio with --create_serialize=0 and --numjobs=2
you will instead see that ->init() callback will be called for each
thread, before the ->setup() callback is called for each thread:
my_fio_init: td: 0x7eff72d6a000
my_fio_init: td: 0x7eff72daea70
my_fio_setup: td: 0x7eff72d6a000
my_fio_setup: td: 0x7eff72daea70
This is because, in backend.c:thread_main() looks like this:
...
if (!init_iolog(td))
goto err;
if (td_io_init(td))
goto err;
if (init_io_u(td))
goto err;
...
if (!o->create_serialize && setup_files(td))
goto err;
if (!init_random_map(td))
goto err;
...
td_io_init() will call td->io_ops->init(td) and setup_files() will
call td->io_ops->setup(td).
Is it just me who thinks that it is extremely confusing for an ioengine
developer to not be able to know if the ->setup() or ->init() callback
will be called first?
Should we perhaps consider moving the
if (!o->create_serialize && setup_files(td))
goto err;
chunk so that it is before the td_io_init() call?
That way, ->setup() would always be called before ->init()
(which is the default, since --create_serialize defaults to 1),
no matter what value --create_serialize is set to.
Kind regards,
Niklas
