On 2014-06-30 16:09, Abutalib Aghayev wrote:
>
> On Mon, Jun 30 2014 at 17:50 PM, Jens Axboe <axboe@kernel.dk> wrote:
>> On 2014-06-29 11:43, Abutalib Aghayev wrote:
>>>
>>> This is a quick and dirty patch to log offsets of I/O operations as
>>> well.  It is useful if you would like to make offset vs latency plot for
>>> random I/O, which may not be interesting to many people, so feel free to
>>> ignore it.
>>
>> I can definitely see this being useful. But adding 8 bytes to every log
>> entry complicates things, as fio is already memory intensive there when
>> logging longer runs.
>>
>> I'd suggest having two logging types:
>>
>> struct io_sample {
>>             uint64_t time;
>>             uint64_t val;
>>             uint32_t ddir;
>>             uint32_t bs;
>>             uint64_t offset;
>
> I assume you didn't mean offset being here as well.

Ah no, of course not.

>> struct io_sample_offset {
>>             struct io_sample s;
>>             uint64_t offset;
>> };
>>
>> and using the right type for what you are logging. This means you'd need
>> an option to switch on the offset logging, and that you'd need to store
>> this in the iolog struct (whether to log offset or not) and use the
>> appropriate size for allocating and extending the log entries when needed.
>>
>> Make sense?
>
> Yes, let me rework the patch.

Thanks! Note that you also need to handle the client/server part. 
Half-assed attempt attached, not tested at all. Still needs the client 
part update.


-- 
Jens Axboe