Unable to replay blktrace with mixed workload

Unable to replay blktrace with mixed workload

[Brandon Schwartz]

Using FIO 2.2.7, I'm trying to replay the following workload
(capturing it with blktrace and replaying with FIO on the same device)

 sudo fio --name=rwmix --filename=/dev/sdd --blocksize=128k
--readwrite=randrw --rwmixread=75 --rwmixwrite=25 --runtime=60

And I get the following error:

fio: pid=21428, err=12/file:memory.c:242, func=iomem allocation,
error=Cannot allocate memory

Older versions of FIO (2.1.*) seem to be able to replay the blktrace
without that error, but those versions of FIO don't always seem to
respect the timing of IOs (if there is idle time for example).

Any idea what could be causing the problem?

Regards,
Brandon

Re: Unable to replay blktrace with mixed workload

[Jens Axboe]

On 04/23/2015 01:55 PM, Brandon Schwartz wrote:
> Using FIO 2.2.7, I'm trying to replay the following workload
> (capturing it with blktrace and replaying with FIO on the same device)
>
>   sudo fio --name=rwmix --filename=/dev/sdd --blocksize=128k
> --readwrite=randrw --rwmixread=75 --rwmixwrite=25 --runtime=60
>
> And I get the following error:
>
> fio: pid=21428, err=12/file:memory.c:242, func=iomem allocation,
> error=Cannot allocate memory
>
> Older versions of FIO (2.1.*) seem to be able to replay the blktrace
> without that error, but those versions of FIO don't always seem to
> respect the timing of IOs (if there is idle time for example).
>
> Any idea what could be causing the problem?

There were a few bugs in there. Can you try current -git? Just committed 
a change that should improve things for you.

-- 
Jens Axboe

Re: Unable to replay blktrace with mixed workload

[Brandon Schwartz]

Thanks, but now it seems to convert the blktrace replay into all reads
and increase the run time to 20minutes (from 60seconds).

fio-2.2.7-24-g7c30 is the latest right?



On Fri, Apr 24, 2015 at 9:04 AM, Jens Axboe <axboe@kernel.dk> wrote:
> On 04/23/2015 01:55 PM, Brandon Schwartz wrote:
>>
>> Using FIO 2.2.7, I'm trying to replay the following workload
>> (capturing it with blktrace and replaying with FIO on the same device)
>>
>>   sudo fio --name=rwmix --filename=/dev/sdd --blocksize=128k
>> --readwrite=randrw --rwmixread=75 --rwmixwrite=25 --runtime=60
>>
>> And I get the following error:
>>
>> fio: pid=21428, err=12/file:memory.c:242, func=iomem allocation,
>> error=Cannot allocate memory
>>
>> Older versions of FIO (2.1.*) seem to be able to replay the blktrace
>> without that error, but those versions of FIO don't always seem to
>> respect the timing of IOs (if there is idle time for example).
>>
>> Any idea what could be causing the problem?
>
>
> There were a few bugs in there. Can you try current -git? Just committed a
> change that should improve things for you.
>
> --
> Jens Axboe
>