Re: [Question] How to perform stride access?

[Akira Hayakawa <ruby.wktk@gmail.com>]

Andrey,

> You might want to specify iosize or use a time-based run.
Could you explain the difference between bs and iosize?
My understanding is bs option specifies the iosize.
Do you mean I need to add "--size=32M"?

time-based won't help in my case because I want to see
the runtime of 32MB writes consumed.

- Akira

On 9/24/14 6:10 PM, Andrey Kuzmin wrote:
> You might want to specify iosize or use a time-based run.
> 
> Regards,
> Andrey
> 
> On Sep 24, 2014 12:35 PM, "Akira Hayakawa" <ruby.wktk@gmail.com <mailto:ruby.wktk@gmail.com>> wrote:
>>
>> Thanks Andrey,
>>
>> However, I don't think I still have a problem.
>>
>> I modified the command
>>
>> From:
>> >> fio --name=test --filename=#{dev.path} --rw=write --ioengine=libaio --direct=1 --io_limit=32M --size=100% --ba=4k --bs=512
>> To:
>> fio --name=test --filename=#{dev.path} --rw=write:4k --ioengine=libaio --direct=1 --io_limit=32M --bs=512
>>
>> The result is the runtime is too short.
>> I guess fio stops as soon as it reaches the end of the device.
>> However, I want it to repeat over and over again until io_limit is fully consumed.
>>
>> Note that the device is smaller than 32M (it is only 508B).
>> So, it should repeat more than 60 times.
>>
>> How can I repeat the workload?
>>
>> Or,
>>
>> Building hand-made random map would suffice, I guess.
>>
>> - Akira
>>
>>
>> On 9/23/14 11:05 PM, Andrey Kuzmin wrote:
>> > Offset modifier under rw= should do the trick, consult
>> > https://github.com/axboe/fio/blob/master/HOWTO for details.
>> >
>> > Best regards,
>> > Andrey
>> > Regards,
>> > Andrey
>> >
>> >
>> > On Tue, Sep 23, 2014 at 5:47 PM, Akira Hayakawa <ruby.wktk@gmail.com <mailto:ruby.wktk@gmail.com>> wrote:
>> >> Hi,
>> >>
>> >> I want to perform stride write access to a block device but
>> >> I don't have a clue how I can do that.
>> >>
>> >> What I want to do is to perform a stride access that
>> >> each write size is 1 sector and 7 sectors are apart between each writes.
>> >> (i.e. Only the first sector of each 4KB block)
>> >>
>> >> For example,
>> >> 0, 8, 16, 24, 32, ...
>> >>
>> >> And, it repeat over the device until certain amount of writes are accomplished.
>> >> In my case, amount of 32MB to 508KB device.
>> >>
>> >> I consider the command below works like as I want but it doesn't actually.
>> >> Instead, it looks performing ordinary 512KB seq write.
>> >> fio --name=test --filename=#{dev.path} --rw=write --ioengine=libaio --direct=1 --io_limit=32M --size=100% --ba=4k --bs=512
>> >>
>> >> My questions are:
>> >> 1) How to perform stride write access in fio?
>> >> 2) If fio is not a appropriate tool for this purpose, easy to fix?
>> >>    Or do you recommend other tool?
>> >>
>> >> - Akira
>> >> --
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>