Re: If loops= is specified, zone state is unexpectedly retained across iterations.

[Jens Axboe <axboe@kernel.dk>]

On 2014-09-25 11:36, Akash Verma wrote:
> Adding Jens on cc.
>
> On Tue, Sep 23, 2014 at 6:02 PM, Akash Verma <akashv@google.com> wrote:
>> I'm wondering if this is desired behavior or accidental. If I use this
>> control file:
>>
>> [sdb-zoned-and-looped]
>> rw=write
>> bs=4k
>> size=24k
>> zonesize=12k
>> zonerange=512k
>> zoneskip=512k
>> ioengine=sync
>> direct=1
>> thread=1
>> loops=10
>> filename=/dev/sdb
>> write_iolog=sdb_iolog.txt
>>
>> sdb_iolog.txt shows:
>> fio version 2 iolog
>> /dev/sdb add
>> /dev/sdb open
>> /dev/sdb write 0 4096
>> /dev/sdb write 4096 4096
>> /dev/sdb write 8192 4096
>> /dev/sdb write 1048576 4096
>> /dev/sdb write 1052672 4096
>> /dev/sdb write 1056768 4096
>> /dev/sdb close
>> /dev/sdb open
>> /dev/sdb write 1048576 4096
>> /dev/sdb write 1052672 4096
>> /dev/sdb write 1056768 4096
>> /dev/sdb write 2097152 4096
>> /dev/sdb write 2101248 4096
>> /dev/sdb write 2105344 4096
>> ...
>>
>> I'd expect each iteration of the loop to be identical, rather than
>> resuming from the zone offset of the previous iteration. Would it be
>> okay to change this behavior?

Yeah I think that would be OK, basically all state is cleared between 
loops, so I'd consider that a bug. The whole point of a loop is that 
they are supposed to be identical.

-- 
Jens Axboe