[Disksim-users] Why the overall average response time, almost 20000, is so big?

[leon hsu]

That's very helpful. I will change the trace and test them again.

Thanks for YueYingLiang and Anjo,

Your response gets me out of my problem.

Leon

On Tue, Aug 14, 2012 at 3:33 AM, Yinliang Yue <yueyinliang at gmail.com> wrote:

> I have noticed that the average time interval between two I/O requests is
> too small.  The first column means the I/O arrive time (ms), you issued 33
> I/Os in 8.8ms.  The average time interval between two I/O requests is only
> 0.27ms.  However, the disk I/O access time (access time = data transfer
> time + rotation time + seek time) is far larger than 0.27ms.  There are too
> many pending I/O requests in the waiting queue and so the average response
> time is Incredibly large.
>
>
> 2012/8/14 leon hsu <liangxiongxu at gmail.com>
>
>> Hi yueyinliang,
>> Hopefully, the name is same with your mail: ) Thanks for you reply.
>>
>> The attaching file is the hard disk configuration.  I only have one hard
>> disk.
>>
>> Could you take a look and check the configuration for me? Thank you so
>> much.
>>
>> The ascii trace looks like this:
>>
>> 0    0    0    24    0
>> 0    0    0    24    1
>> 1    0    24    16    0
>> 1.5    0    40    16    0
>> 2    0    56    16    0
>> 2.2    0    72    16    0
>> 2.4    0    88    16    0
>> 2.6    0    104    16    0
>> 2.8    0    120    16    0
>> 3    0    136    8    0
>> 3.125    0    144    8    0
>> 3.25    0    152    8    0
>> 3.375    0    160    8    0
>> 3.5    0    168    8    0
>> 3.625    0    176    8    0
>> 3.75    0    184    8    0
>> 3.875    0    192    8    0
>> 4    0    200    8    0
>> 4.333333    0    208    8    0
>> 4.666667    0    216    8    0
>> 5    0    224    8    0
>> 5.333333    0    232    8    0
>> 5.666667    0    240    8    0
>> 6    0    248    8    0
>> 6.333333    0    256    8    0
>> 6.666667    0    264    8    0
>> 7    0    272    16    0
>> 7.5    0    288    16    0
>> 8    0    304    16    0
>> 8.2    0    320    16    0
>> 8.4    0    336    16    0
>> 8.6    0    352    16    0
>> 8.8    0    368    16    0
>>
>>
>>
>> Leon
>>
>>
>>
>> On Sun, Aug 12, 2012 at 11:24 PM, Yinliang Yue <yueyinliang at gmail.com>wrote:
>>
>>> There are so many I/O requests waiting in the queue. I do not know the
>>> details of your storage systems, such as how many disks, how these disks
>>> are organized. I suggest you check your storage configuration.
>>>
>>> 2012/8/13 leon hsu <liangxiongxu at gmail.com>
>>>
>>>>
>>>> Hi, everybody,
>>>>
>>>> I need you help:-)
>>>>
>>>> When I set the "I/O Trace Time Scale" in disksim_iosim to 1, the
>>>> simulator shows a saturation error before.
>>>> But when I change "I/O Trace Time Scale" in disksim_iosim to 10, the
>>>> error disappeared.
>>>>
>>>> I think that is because the "request arrival time" of the trace file is
>>>> too small, which results that the number of the arriving requests in one
>>>> second is more than ones that the simulator could deal with in one second.
>>>> So I change the "I/O Trace Time Scale" in disksim_iosim to 10.
>>>>
>>>> Next, I run it again, but the weired result made me crazy. When I ran
>>>> disksim using my ascii trace file, the overall response time, almost 20000,
>>>> is too big to believable.
>>>>
>>>> Do anybody could tell me the reason and how to solve this problem.
>>>> Thank you so much. I am so appreciated.
>>>>
>>>>
>>>> I set the "request arrival time" like the following style.
>>>>
>>>> 0.5
>>>> 0.75
>>>> 1
>>>> 1.2000
>>>> 1.4000
>>>> 1.5000
>>>> 1.7000
>>>> 2.0
>>>> .....
>>>>
>>>>
>>>> Hopefully, it could give some hints to find out my problem. Thanks.
>>>>
>>>>
>>>> Leon
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Disksim-users mailing list
>>>> Disksim-users at ece.cmu.edu
>>>> https://sos.ece.cmu.edu/mailman/listinfo/disksim-users
>>>>
>>>>
>>>
>>>
>>> --
>>>         此致
>>> 敬礼
>>>
>>> 岳银亮
>>>
>>>
>>
>>
>> --
>>
>> Cailiang Xu
>>
>> Tel: 732.789.6683
>>
>> Email: liangxiongxu at gmail.com
>>
>> Computer Architecture & System Lab
>> <liangxiongxu at gmail.com>
>>
>>
>
>
> --
>         此致
> 敬礼
>
> 岳银亮
>
>


-- 

Cailiang Xu

Tel: 732.789.6683

Email: liangxiongxu at gmail.com

Computer Architecture & System Lab
<liangxiongxu at gmail.com>
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