[Disksim-users] Cannot have 2 synthetic workload generators - 1 for time-critical, 1 for time-noncritical requests

[Yipkei Kwok]

Dear Disksim users,

This is what I want to simulate.
* 3 concurrent synthetic workload generators
* the 1st 2 generate time-critical requests (i.e. each may have only 1
pending request)
* the 3rd generates time-noncritical requests (i.e. may have >1 pending request)

I posted the Disksim parameter files (.parv) and output files (.outv)
on my website. Please note that, for some reason, I have to append the
file names with ".txt" on the web site.

Settings
* I created my parameter file
(http://utminers.utep.edu/ykwok2/tmp/synthopen.3.parv.txt) based on
synthopen.parv that comes with the Disksim 4.0
* there are 3 disks. Each synthetic generator accessed its own disk
* changes I made
i. Number of processors
synthopen.parv:    1
synthopen.3.parv: 3
ii. "Probability of time-critical request" of the 1st 2 synthetic generators
synthopen.parv:    0.0 (i.e. Probability of time-critical request =  0.0)
synthopen.3.parv: 1.0 (i.e. Probability of time-critical request =  1.0)

Problem:
* The 1st 2 synthetic workload generators, each, generated only 1
request. After the requests were serviced, they did not generate
another request.

Details:
* output file (http://utminers.utep.edu/ykwok2/tmp/synthopen.3.outv.txt)
* I got into this problem on an unmodified version of Disksim 4 (vanilla).
* Number of requests generated by each generator.
$ grep -i 'Number of I/O requests' ./synthopen.3.outv
Process Number of I/O requests:  10002
Process 3 Number of I/O requests:  1
Process 4 Number of I/O requests:  1
Process 5 Number of I/O requests:  10000

* Number of requests serviced by the disks
$ grep -i 'total requests handled' ./synthopen.3.outv
Overall I/O System Total Requests handled:      10001
IOdriver Total Requests handled:        10001
IOdriver #0 device #0 Total Requests handled:   1
IOdriver #0 device #1 Total Requests handled:   1
IOdriver #0 device #2 Total Requests handled:   9999

Note:
* this problem does not happen when either all synthetic generators
generate time-critical or all synthetic workload generators generate
time-noncritical accesses.
* Case I: all generators generate time-critical access
Parameter file: http://utminers.utep.edu/ykwok2/tmp/synthopen.2.parv.txt
Output file:      http://utminers.utep.edu/ykwok2/tmp/synthopen.2.outv.txt
$ grep -i 'total requests handled' ./synthopen.2.outv
Overall I/O System Total Requests handled:      10001
IOdriver Total Requests handled:        10001
IOdriver #0 device #0 Total Requests handled:   3387
IOdriver #0 device #1 Total Requests handled:   3253
IOdriver #0 device #2 Total Requests handled:   3361
* all generators generate time-noncritical access
Parameter file: http://utminers.utep.edu/ykwok2/tmp/synthopen.5.parv.txt
Output file:      http://utminers.utep.edu/ykwok2/tmp/synthopen.5.outv.txt
$ grep -i 'total requests handled' ./synthopen.5.outv
Overall I/O System Total Requests handled:      9998
IOdriver Total Requests handled:        9998
IOdriver #0 device #0 Total Requests handled:   3438
IOdriver #0 device #1 Total Requests handled:   3313
IOdriver #0 device #2 Total Requests handled:   3247


Looking forward to hearing from you. Thank you very much.

Regards,
Yipkei

--
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Yipkei Kwok
Ph.D. Student
Research Assistant
HiPerSys Lab
Department of Computer Science
The University of Texas at El Paso
Phone: 915 747 6433 (O)
E-mail: ykwok2 at miners dot utep dot edu
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