Actuar Aplicar ajustes
PROCESO DE INVENTARIO MANUAL DE PROCESOS
Seven distinct simulation runs were performed. The systems configuration simulated as well as the results produced by each simulation run, are presented and discussed in the following subsections of this chapter.
In all cases the system is considered to be under constant load. It is
a~sumed therefore, that there are always batch tasks waiting to be processed.
It is also assumed that all the remote terminals, included in the configuration of the system, are active during the simulated period in which statistics about the systems performance are gathered.
Upon construction, the demand drive workload consists of fewer tasks than the batch drive workload. Also the demands placed on the systems resources by demand tasks are generally fewer than the demands placed by batch tasks.
Finally, the model gives preference to demand tasks over the batch ones.
The above reasons result in all the demand tasks, included
hi
the demand' .
drive workload, to be processed before the processing of all the batch tasks, of the batch drive workload, is completed. Since our original intention was to investigate the system under constant load, as it was stated in the previous
paragraph, each run was terminated when almost all the demand tasks, included in the demand drive workload, were processed through the model.
At simulation time 0 of each simulation run, a number of transactions, f:qual to the munbcr of tasks included in the drive workload, is generated and are scheduled to move through the model. A number of transactions, determined
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by the values of the savex entities "lVIAXOPENn and 11MAXDOPEN';, move further down in the model, i.e. they enter the core, are placed in
DYNAL.Q, etc. The remaining transactions are linked into the appropriate user defined chain entities. In this way, in order for the model to stabilize, it was estimated that, less than 300 msecs of simulated time are required.
This time represents some 0.03% of the total simulation time of the shortest as far as the total simulation time is concerned, of the seven runs performed • . Normally in running a simulation; it is important to run it for long enough
for the model to stabilise before the collection of the results is initiated, (MARTIN, 1967 ). In our case, since the time required for the model to stabilise is very small, compared with the total simulation time, it was
·thought to be unnecessary to allow the model to stabilise before the gathering of statistics is initiated.
Case 1.
In the first case, the model runs with the following systems characteristics:
One central processiD..g unit.
Core available to user tasks, 128 .blocks of 5121 36-bit, words each.
One disc subsystem, \vith four disc drives attached to it, having:
minimum seek time 25 msecs average seek time 60 msecs maximum· seek time 130 msecs Disc drive speed 2400 rpm
'
(25 msecs per revolution)
Transfer rate 14.4 microseconds/word. These are the characteristics of the 8414 disc subsystem.
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One drum subsystem with one drum unit attached to it with, Drum rotational speed 1770 rpm (34 msecs per revolution) Transfer rate 8. 2 microseconds/word
These are the characteristics of the FH-1782 drum subsystem.
One magnetic tape subsystem with two recording units attached to it with start/stop
...
... I me 8 msecsTransfer rate 46.9 microsecs/word
These are the characteristics of the UNISERVO 16N magnetic tape subsystem.
Maximum permissible number of batch jobs to 'be opened concurrently 8 Number of demand terminals 8
The above characteristics reflect the configuration of the UNIVAC 1106 under the EXEC 8 operating system that existed at U. C. T. 's computer centre up to
June 1974.
The results of the first simulation run are presented in the figures A-1 through to A-13.
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In the design of the report editor, our primary concern was to make the report generated at the end of each simulation run, as self explanatory as possible. However> it was found necessary that some additional explanations should be given in order to further facilitate the analysis and interpretation of the results. The following explanations are given in accordance to the report pro(Juced by the first simulation run. These explanations are also valid for the remaining six rtms. This is because the items which appear. in the
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figures A-1 through to A-13 of the first simulation run, correspond to those items which appear in figures B-1 to B-13 of the second simulation run and in the same order, correspond to those items which appear in figures C-1 to C-13 of the third simulation run and so forth.
In each item which expresses ''time", this time is given in milliseconds.
The first item of figure A-1 under the heading "CLOCK TIME IN MILLISECONDS", expresses the total simulation time for which statistics about the system were - collected.
In figure A-2 the first, second, fourth, fifth and seventh items of the first row of information, are expressed in blocks of 512, 36-bit, words.
The maximum multiprogramming factor, (first item of the second row of information of figure A-2), is the maximum number of tasks ever found to be in core concurrently.
The average multiprogramming factor, (second item of the second row of figure A-2), refers to the average number of tasks being in core concurrently at any instant during the simulation period.
The first item of the third row of information of figure A-2 refers to the total number of tasks loaded into core during the simulation.
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so.
The item in the fourth row of figure A-2 is the total number of tasks swapped out during the simulation.
The item in the fifth row of figure A-2 refers to the number of times the DAPA routine adjusted the core priority of a batch task, subject to the demand/batch sharing requirements.
The fourth item of the first row in figures A-3, A-4, A-5, A-6 refers to those entries which spend no time in the corresponding queue because they
·are able to leave the queue without delay.
The average utilization of the various facilities is given in the form of the percentage of the total simulation time during which the corresponding facility was busy.
In figures A-7 and A-8 statistics about the response and turnaround times are given in a tubular form.
"UPPER LIMIT11 is the largest allowed observed value of the argument for each equivalence class in the table.
"OBSERVED FREQUENCY!! is the total number of observed values of the argument which are w-ithin each equivalence class in the table.
"PERCENT OF TOTAL'1 is a quotient, i.e. the observed frequency, multiplied by 100, divided by the total number of observed values of the argument.
"CUMULATIVE PERCENTAGE" is the total percentage of all observed values of the argument which are less than or equal to each upper limit.
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In order to facilitate the analysis of the results of each simulation run, the
.•
utiiization of the CPU, the drum channel, the drum drives, the disc channel, the disc drives and the tape channel are given in a histogram type form in figure A-9. Histograms of the response time percentage, response time cumulative percentage, turnaround time percentage and turnaround cumulative percentage are given in figures A-10, A-11, A-12 and A-13 respectively.
An examination of the results produced shows that in 1. 663 882 msecs of total simulation time, 300 tasks were processed, out of which 158 were
· batch tasks. That would result in an average batch throughput rate of 348 batch tasks;'110ur. The average turnaround time for each task was found to
be
about 55,54 seconds and the average response time to the corresponding terminal to be 4, 85 seconds.The average task size processed is 27.67 blocks and the average multipro-gramming factor 2. 45.
The CPU, disc subsystem and drum subsystem statistics, show that the systems component with the highest utilization was the CPU with average utilization 50. 6%. A bottleneck situation \VOuld appear on a subsystem, if this subsystem is utilized at about 100% of the total time. Thus the system is rather far from its maximum capacity. A natural explanation is that the system has insufficient core store. There are, of course other possible explanations such as:
(a) Too few jobs are open simultaneously resulting in a limited number of requests for core.
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(b) The core allocation algorithm does 11ot make full use of the available core space.
Alternative (a) is eliminated at once because the average length of the
-core queue is found to be 6. 98. Alternative (b), initially appears to be a possible explanation since the average utilization of the core was found
to be 75,62%. But as it will be seen in the following simulation runs, where the model assumes 384 core blocks available to the user programs, the average core utilization never drops below. 90%. Thus the 75.62% average utilization of the core, is ratl:..er due to the size of the programs in the workload, than in the inefficiency of the core allocation algorithm.
From the above it is concluded that, the limited CPU utilization, which eventually results in the systems limited productivity is due to insufficient
core space.
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CLOCK TI~~ l~ ~!LLI~~CC~JS
==-=-============-=-======
lb53b3Z .
~0~9[~ OF TASKS. ?RCCESSED
bATCM TvT~L
142 300
NU~eER OF JU~S ~LLOWED TO BE OPE~EO CONCURRENTLY:
cATCH ClMAhU
8 B
NUMBER OF JObS LURRlNTLY CFEN:
~ATCK
8
Fig. A-1
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84.
CAPAC:TY CCNTlNT::. LJT.::...IZATIUi-: BL::v~S TP.SK\ s.rz::-- P£:R BLOC!{ CC~-:TE:t\TS
PRCGRA~~I~G FACT~R
7
TuTAL ~0 ..
ul- LO.A US
9tl.9
AV£RAG[. T.;:Ml IN C.:C.k( PER :...CAC
TJTAL NUMBER OF SWAPS
~G. OF CORE PR!GRlTY ~UJUSTME~TS:
l
CCRE ~UtUE AVLRAGi LENGTH
TASKS CURRENTLY Ih COR£
l
Fig. A-2
-,~
• t j 117
, ... ~ _,
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CPU S T A T I S T I C S
=======~==================
MAX .PUELJE AVE .QLJEtiE LENGTH LENGTH
6 • 33
TOTAL ENTRIES
4~118
ZERO ENTRIES
29181
ZERnS PERCENT
72.74
A\f. TIME/ENT (NON· ZERO)
5~.3?
RATE OF ARRIVAL OF REQUESTS FOR SERVICE AY THE CPU
---~---TABLE NAME: T {
4)
REQUESTS OBSERVEO PER SEC FREQUENCY
-~~~0 0
2s.mae0 9m3
5~.0000 716
'75.0~0~ 44
CUMULATIVE
P ERGE NT AC7E
.~~
54. 30 . 97.35 .100. !Hf PERCENT
OF TOTAL .00 54.30
43.~5
2.65 ALL ZERO.
REMAINING FREQUENCIES ARE
AVERAGE NUMBER OF.AEQUESTS FOR SERVICE PER SECOND
24.116
WAITING TIME FREf.HJENCY TABLE (IN CLASSES OF 1 SECOND ) TARLE NM~E: T ( B)·
UPPER LIMIT 10ra0.!HH30 2000.0000 3000.0000
4~00.0000
nBSERVED FREQUENCY
4~072
45
0 1
PERCENT OF TOTAL 99.89
• 11 .00 .0!1 REMAINING FREQUENCIES ARE ALL ZERO
AVERAGE WAITING TIME
13.731
CPU UTILIZATION
_______________
...AVERAGE NUMBER UTILIZATION REQUESTS
50.6036 40118
AVERAGE TIME/REQ
~0.99
CUMULATIVE PERCENTAGE.
99.89 100.00 10ta.00 100.00
Fig. A-3
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S U 8. S Y S T E M S S T A T I S T I C S
A. ORUM SUBS YSTD~
MAX.QUEUE AVE.L:!UEUE LENGTH LENGTH
7 .32
1 OTAL ENTRIES
25825
ZERO ENTRIES
15153
ZEROS PERCENT
58.68
AV. TIME/ENT (NDN ZERO)
5~.21
RATE OF ARRIVAL OF REQUESTS FOR SERVICE AY THE DRUM SUBSYSTEM ---~---TABLE NAME: T { 1)
REQUESTS OBSERVED PER SEC FREQUENCY
.00!H~ 0··
25.00~0 1329
50.0000 334
PERCENT OF TOTAL
REMAINING FREQUENCIES ARE
.v.1~
79.92 20.08 ALL ZERO
CUMULATIVE PERCENTAGE
• f.H3 79.92 100.00
AVERAGE NUMBER OF REQUESTS FOR SERVICE PER SECOND
15.526
WAITING T~ME FREQUENCY TABLE (IN CLASSES OF 1 SECOND ) TARLE NAME: T { 5)
UPPER OBSERVED PERCENT CUMULATIVE LIMIT FREQUENCY OF TOTAL PERCENTAGE 10v.10.0000 25823 99.99 99.99
2000.0000 2 .B1 100.!0
REMAINING FREQUENCIES ARE ALL ZERO AVERAGE WAITING. TIME
20.748
CHANNEL AND UNIT UTILIZATIONS
CHANNEL AVERAGE NU~~BER AVERAGE
NAME UTILIZATION REQUESTS TIME/REQ
F ( 1) 16.6703 25825 10.74
UNIT AVERAGE NUMBER AVERAGE
NAME UTILIZATION REQUESTS TIME/REQ
ORU 1 43.1326 25825 27.79
Fig.
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MAX.QLJEUE AVE. QUEUE TOTAL ZERO ?:.EROS LENGTH LENGTH ENTRIES ENTRIES PERCENT
3 • 11 12113 9555 78.88
'RATE DF ARRIVAL OF REQUESTS FOR SERVICE RY THE TARLE NAME: T ( 2)'
PERCENT OF TOTAL
.0e
99.94 .06 REMAINING FREQUENCIES ARE ALL ZERO REQUESTS
PER SEC
.00~0 25.0~0~
50. ~01HJ
OBSERVEO FREQUENCY
0
1662
1
;
CUMULATIVE PERCENTAGE
• ~ 0
99.94
100e~0
A\1. TIME/ENT (NON ZERd)
68.94 DISC SUBSYSTEM
AVERAGE NUt,mER OF REQUESTS FOR SERVICE PER SECOND
7.281
WAITING TIME FREQUENCY TABLE (IN CLASSES OF 1 SECOND } , TABLE NAME: T ( 6)
UPPER OBSERVE[) PERCENT LIMIT FREQUENCY DF TOTAL
10~0.~000 12113 100.00 REMAINING FREQUENCIES ARE 'At~l ZERO
AVERAGE WAITING TIME
14.559
CHANNEL AND UNIT UTILIZATIONS CHANNEL AVERAGE NUf..1AER
NAME UTILIZATION REQUESTS
F ( 2) 7.3124 12113
UNIT AVERAGE NUMBER
NAME UTILIZATION REQUESTS
DU1 18. 5f386 3040
[)LJ 2 18. 1197 2976
DU3 19.~321 3082
DU4 18.4778 3015
CUMULATIVE PERCENTAGE
100.1110
AVERAGE' TIME/REQ
11!1.1114 AVERAGE TIME/REQ
101.74' 101.31 102.75 101.97 Fig.
A-5
..
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