On 4 September 2017 at 20:48, Tomohiro Kusumi <kusumi.tomohiro@xxxxxxxxx> wrote:
> 2017-09-04 22:36 GMT+03:00 Sitsofe Wheeler <sitsofe@xxxxxxxxx>:
>> Hi,
>> On 4 September 2017 at 16:23, <kusumi.tomohiro@xxxxxxxxx> wrote:
>>> From: Tomohiro Kusumi <tkusumi@xxxxxxxxxx>
>>>
>>> 8c43ba62('filesetup: align layout buffer') and
>>> 6e344dc3('filesetup: keep OS_O_DIRECT flag when pre-allocating file')
>>> need to keep the valid transfer size throughout the entire writes.
>>>
>>> The write(2) size may be truncated on the last write and break the
>>> dio requirement. This results in td_verror() in the output.
>>>
[...]
>>> ---
>>> filesetup.c | 13 ++++++++++---
>>> 1 file changed, 10 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/filesetup.c b/filesetup.c
>>> index 5e8ea35..42d95db 100644
>>> --- a/filesetup.c
>>> +++ b/filesetup.c
>>> @@ -112,6 +112,7 @@ static int extend_file(struct thread_data *td, struct fio_file *f)
>>> unsigned long long left;
>>> unsigned int bs, alloc_size = 0;
>>> char *b = NULL;
>>> + bool done = false;
>>>
>>> if (read_only) {
>>> log_err("fio: refusing extend of file due to read-only\n");
>>> @@ -211,11 +212,15 @@ static int extend_file(struct thread_data *td, struct fio_file *f)
>>> goto err;
>>> }
>>>
>>> - while (left && !td->terminate) {
>>> + while (!done && !td->terminate) {
>>> ssize_t r;
>>>
>>> - if (bs > left)
>>> - bs = left;
>>> + /* If bs >= left this is the last write */
>>> + if (bs > left) {
>>> + done = true;
>>> + if (!td->o.odirect)
>>> + bs = left;
>>> + }
>>>
>>> fill_io_buffer(td, b, bs, bs);
>>>
>>
>> Hmm. Won't this result in a file that is bigger than requested when
>> direct=1 and the maximum bs isn't an exact multiple of the extended
>> filesize? Should it start trying the minimum block size at this stage
>> with direct=1? If that goes on to not fit wouldn't it be better to do
>> less given that the main fio job won't be able to fill the gap either?
>
> The td's are also under the dio requirements.
> If you really want the exact size, you can truncate(2) it.
Technically didn't fio already truncate the file to the correct size
prior to starting direct layout over on
https://github.com/axboe/fio/blob/d33db728d79386d544be93c24f4e3383f2a47143/filesetup.c#L191
?
--
Sitsofe | http://sucs.org/~sits/
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