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

[Anjo Vahldiek]

Hi,

As Yinliang said the queuing time should account for the high response 
times. You can lookup the avg. queue time in the output statistics. 
Also the avg. queue length is recorded. You may need to enable the 
statistics in your .parv file.

Anjo

On Tue 14 Aug 2012 12:33:44 PM CEST, Yinliang Yue 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
> <mailto: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 <mailto: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
>         <mailto: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
>
>
>
>
>
>
>
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>
>
>
>
>         --
>                 此致
>         敬礼
>
>         岳银亮
>
>
>
>
>     --
>
>     Cailiang Xu
>
>     Tel: 732.789.6683
>
>     Email: liangxiongxu at gmail.com <mailto:liangxiongxu at gmail.com>
>
>     Computer Architecture & System Lab
>     <mailto:liangxiongxu at gmail.com>
>
>
>
>
>
> --
>         此致
> 敬礼
>
> 岳银亮
>
>
>
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