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- Measuring Performance in the Extended Print Service Environment
-
- Rich Lee
- Senior Consultant
- Systems Engineering Division
-
- Abstract:
- NetWare print services can be configured for both simple and complex LAN
- printing environments. After reviewing several concerns from the low#end
- environment, this AppNote focuses on complex printing environments where many
- users send jobs to a single print queue. It discusses the issues involved in
- high#end printing environments and presents the results of some print service
- performance tests in these environments. LAN designers and managers will find
- several new techniques for predicting printing performance across the LAN.
-
- Disclaimer
-
- Novell, Inc. makes no representations or warranties with respect to the
- contents or use of these Application Notes (AppNotes) or of any of the
- third#party products discussed in the AppNotes. Novell reserves the right to
- revise these AppNotes and to make changes in their content at any time,
- without obligation to notify any person or entity of such revisions or
- changes. These AppNotes do not constitute an endorsement of the third#party
- product or products that were tested. Configuration(s) tested or described
- may or may not be the only available solution. Any test is not a
- determination of product quality or correctness, nor does it ensure
- compliance with any federal, state or local requirements. Novell does not
- warranty products except as stated in applicable Novell product warranties or
- license agreements.
-
- Copyright { 1991 by Novell, Inc., Provo, Utah. All rights reserved.
-
- As a means of promoting NetWare AppNotes, Novell grants you without charge
- the right to reproduce, distribute and use copies of the AppNotes, provided
- you do not receive any payment, commercial benefit or other consideration for
- the reproduction or distribution, or change any copyright notices appearing
- on or in the document.
-
- Contents
-
- Introduction 5
-
- What Are Extended Print Services? 5
-
- Why Study Extended Print Services? 5
-
- Review of the Low#End Printing Environment 6
-
- The Low#End Printing Model 6
-
- Measuring Time Required to Print 7
-
- Production Rates for Low#End Printing 8
-
- The Effect of Network Awareness 9
-
- The High-End Printing Environment 9
-
- The High#End Printing Model 9
-
- Number of Users per Printer 10
-
- More Than One Job in the Queue 10
-
- Measuring Print Time with Multiple Print Jobs 11
-
- Defining the Dependent Variables 12
-
- Isolating Application Adding Time 13
-
- Extended Print Service Performance Tests 14
-
- Basic Hardware Configuration 14
-
- What We Measured and Why 14
-
- Parameters for Calculation 15
-
- Start Time 15
-
- Dwell Time 15
-
- Adding Time 16
-
- Activation Time 16
-
- Throughput Time 16
-
- Clear Time 17
-
- Print Time 17
-
- Observations and Test Conclusions 17
-
- Implementation Considerations 19
-
- Calculating Average Queue Utilization 19
-
- Probability Modeling 20
-
- Appendix A: Test Results for Extended Print Services 22
-
- Appendix B: High#End Test Configurations 23
-
- Introduction
-
- This Application Note is a follow#up to the information in the #NetWare Print
- Service Performance" AppNote published in April 1991. Whereas that AppNote
- dealt with measuring print service performance in the low#end printing
- environment, this AppNote looks at the issues connected with measuring
- performance in the high#end or #extended" printing environment. It reviews
- the basic concepts of the low#end printing model, then discusses the
- variables that must be considered in the high#end printing model. After
- explaining the test methodology for extended print services, it presents some
- formulas that can be used in calculating average queue utilization and
- probability modeling.
-
- What Are Extended Print Services?
-
- For our purposes, we will define the ground of extended print services as
- follows:
-
- Any situation in which there is more than one job in the print queue
- at a time is an extended print service##or, more accurately, extends the
- print service.
-
- Basic to the understanding of extended print services is that there is no
- additional supporting software with which you extend your print services.
- Rather, the way you implement applications and hardware configurations
- extends your need for print services beyond the low#end printing environment
- of one job in one queue.
-
- In the extended printing environment, the print service and queue management
- functions do not become active and then go inactive with each print job.
- There are jobs to process beyond the current one. These other jobs in the
- queue extend (by time and job) print service activity; hence, #extended"
- print services.
-
- Why Study Extended Print Services?
-
- Even in low#end printing there can be periods of high usage which look, for
- the short term, very much like high#end. There are studies which indicate
- that even the most innocuous low#end environment may become a veritable
- torrent of printing activity, due more to human nature than to technical
- variables. (We'll look more closely at this phenomenon in a future AppNote.)
-
- Because of the potential intersection of low#end and high#end printing, even
- the low#end environment may present the LAN supervisor with difficulties
- normally encountered in high#end printing scenarios. What's more, users often
- get downright hostile when network printing slows down. For these reasons,
- the LAN supervisor should plan printing resources with the worst case in
- mind, or at least think through the ramifications for the maximum expected
- load. This can be hard to do, and may require gathering information from
- several sources. Hopefully the information in this AppNote will help.
-
- Review of the Low#End Printing Environment
-
- The #NetWare Print Service Performance" AppNote was concerned with measuring
- printing rate (in bytes per second) and production performance (in PPM and
- GPPM) in the low#end environment. It also dealt with determining what aspects
- of printing were production bottlenecks and calculating the throughput of the
- document to the printer. We measured delivery performance using Word Perfect
- 5.0 as our test application. We also briefly mentioned the difference between
- NetWare aware and unaware printing, and working around the CAPTURE command.
-
- In those studies, we came to several conclusions. Primarily, we saw that
- transmission rate is not a very useful measurement of printing performance.
- Rates can be misleading, especially with graphics output. Production
- performance at the printer is a far better measure of printing throughput.
-
- There were some other items of interest. Printing rates overall were slow,
- mainly because the applications just did not format and send the data
- rapidly. Printing at the printer was also slow, especially through serial
- ports. If all printing were done at the typical low#end rate of 2,242 bytes
- per second, high#end printing would suffer.
-
- The Low#End Printing Model
-
- All of this went to further our understanding of the low#end printing model,
- where print jobs must be added to a queue before the print redirection
- process can be attended to by the network print services.
-
- shows how we measured total print time in the low#end scenario (one job in
- the queue).
-
- : Low#end Printing Scenario
-
- Our definition of the low#end environment does not necessarily imply that you
- have a small number of users. It does imply that there is little network
- printing being done (because there is only one job in the queue at any given
- time.) However, the actual amount of setup and maintenance work is
- disproportionate to the amount of printing that takes place. A LAN supervisor
- defining print queues, printer definitions, and printer configurations
- cannot afford to maintain a high#end network using low#end options. Whereas
- a LAN supervisor in the low#end might define one queue for users and provide
- PRINTCON and PRINTDEF definitions for their individual needs, in the high#end
- a print queue might need to be designed for a particular type of printing
- (for instance, letterhead) and other queues might be set for other printer
- specific functions.
-
- Measuring Time Required to Print
-
- The essence of low#end printing is calculating how long it takes to print one
- job. This section gives a quick review of how this can be done.
-
- Production Rates for Low#End Printing
-
- lists typical production rates as determined in our low#end printing tests.
- These rates can be used in determining the time an application takes to
- produce a printed document.
-
- : Production Rates for Low#End Printing
-
- For example, if you want to know how long it would take to print a Graphics
- Only document in WordPerfect you'd need to know the production rate first.
-
- Referring to , you can use the following formula for calculating the
- approximate time to produce a completed document for a specific printer type:
-
- DOCUMENT SIZE (bytes)
- PRINT TIME (sec) = -----------------------------
- (2-1)
- PRODUCTION RATE (bytes/sec)
-
- The variables in this formula are defined as follows:
-
- Document Size = Transmittable size of the document (in bytes)
- by
- document type
-
- Note that this is not the same as the size of the document as it is stored on
- disk. When you send a document to be printed, the size increases because of
- the additional information that is set to the printer. To see the difference,
- use CAPTURE CR = FileName TI=nn and observe the size of the resultant file.
-
- Production Rate = Bytes per second to transmit the document to
- the printer (from the table)
-
- Of course, you also need to know the printer port type (parallel or serial)
- and the document type (G/O, STR, T/G, or T/O) to do the calculation. The
- table only shows the rates for G/O documents sent to an HP PCL#5 printer
- through a parallel port. See the April AppNote for more complete tables.
- Remember also that the printable document size is computed from the printer
- output when the document is sent to the printer.
-
- The Effect of Network Awareness
-
- The rates shown above are for applications that have network#aware printing
- capabilities. Using the CAPTURE command to redirect local printing to the
- network decreases the rate and increases the time to print the document
- considerably. If you want to use an application that does not use
- network#aware printing, the increase in print time may or may not be a
- problem. However, you might contact the program's manufacturer and let them
- know how beneficial the addition of network#aware capabilities would be.
-
- This type of calculation for print time is useful only to someone in the
- low#end printing environment. Once you move into the high#end environment
- (with more than one job in the queue), the methods for calculating how
- quickly a job can be produced change drastically.
-
- The High-End Printing Environment
-
- Having reviewed the low#end printing environment, we are ready to pursue the
- next step of the printing series, which is to further divide the matrix to
- cover more complex situations.
-
- The High#End Printing Model
-
- The contrasts between the low#end and high#end of printing are mainly found
- in:
-
- w the relative organization of the print service structures (which
- print services are selected)
-
- w the reasons behind creating additional print queues (the problem you
- are trying to solve)
-
- w the quantity of print jobs (how much paper is used)
-
- w the frequency of print queue utilization (how many jobs are in the
- queue at a time)
-
- Admittedly, there are more ways of combining the above factors than any one
- article can deal with. We'll focus on print job quantity and the methodology
- used to redirect and complete those jobs. In the low#end there is
- occasionally quantity, but rarely the increased use of options to handle
- additional workload. In the high#end there is often a large quantity of
- print jobs, along with numerous options for handling the workload.
-
- In the high#end model, you have more queues, more users, and usually a longer
- period of time before all current jobs are done. To do any type of prediction
- on how long it will take to get a job printed, you must consider the
- following factors.
-
- Number of Users per Printer
-
- Determining how many people are using each printer is trickier than it seems.
- Often a printer has more than one queue sending work. You may have to
- account for users from different parts of the network before you can study
- the actual printer activity. The following is a rough formula that might help
- you:
-
- N = NP1Q1 + NP1Q2 + ... +NP1(Sn/Qn)
- (2-2)
-
- where
-
- N = Number of user for Printer #1
- NP1Q1 = Number of users sending jobs to Printer #1 via Queue #1
- NP1Q2 = Number of users sending jobs to Printer #1 via Queue #2
- NP1(Sn/Qn) = Number of users sending jobs to Printer #1 via Queue n on Server
- n
-
- More Than One Job in the Queue
-
- The main difference between low#end and high#end printing is that in the
- high#end environment a second print job is already in the queue ready to be
- activated. In this case, the relationship in formula 2-1 relating printing
- time to the length of the document cannot be used. The total time to produce
- the document is now reliant to some degree upon the time in which other
- documents are finished at the printer.
-
- shows the events that must be measured to determine total time to print in
- the high#end environment.
-
- : High#end Printing Scenario
-
- The times labled T0 through T7 will be defined later in this AppNote.
-
- In , the three print jobs arrive in the queue at about the same time. shows
- other possibilities for how jobs can arrive in the queue.
-
- : Three Ways Multiple Jobs Can Arrive in the Queue
-
- Scenario #1 in resembles the low#end model. It is when print jobs start to
- overlap in the queue that we move into the high#end and measuring time to
- print becomes more difficult.
-
- Measuring Print Time with Multiple Print Jobs
-
- Now that we have covered some of the differences between low#end and high#end
- printing environments, we can examine how to measure performance in the
- high#end environment.
-
- In the low#end environment, we measured performance as the total time to
- print divided into the total pages printed:
-
- NUMBER OF PAGES
- PPM (pages/min) = --------------------
- (2-3)
- TIME TO PRINT
-
- The time to print was measured from the job initiation (to) to the printing
- completion time (tn) when the last page came out of the printer.
-
- T (time to print) = tn # to
- (2-4)
-
- In the high#end, the time to print a document is influenced by the number of
- jobs ahead of the one you want to print:
-
- Total Time = T(job #1) + T(job #N) ... + T(your job)
- (2-5)
-
- This creates a difficulty for the designer or supervisor (not to mention the
- user) in that you must be able to predict the number of print jobs to
- determine the amount of hardware that must be allocated, to say nothing of
- the manpower required for preparation and implementation. It changes the
- environment to one where probabilities describe the time to print a document.
-
- Defining the Dependent Variables
-
- In working with extended print service performance, we need to define more
- terms. For our performance testing, we divided the observable print service
- functions into distinctly quantifiable parameters.
-
- Some of the parameters received names based upon a necessary measure; others
- were named from calculated test results. For instance, the time for a print
- job to be added to a queue was seen as distinctly different from the time to
- deliver it to the printer. This parameter was called the Queue Adding time.
- Each of the other distinct functions inherent to the print service function
- were looked at and named in a similar fashion. lists the dependent variables
- we identified
-
- : Dependent Variables for Measuring Extended Print Service Performance
-
- These variables are shown in . TESTDOC would be the job sent by User 1, and
- FINALDOC would be the job sent by User 2. We'll talk more about these
- variables later.
-
- Isolating Application Adding Time
-
- Defining these measurable quantities was not enough. We also had to determine
- if they had a function, what measuring them actually described in the system,
- and what print service was actually responsible for the performance measured.
-
- For instance, T2 (the Adding time) is the difference between t2 (the measured
- time) and to (the time at initiation).
-
- T2 = t2(time at Ready flag) # t0(time at start)
- (2-6)
-
- The resultant T2 is the absolute time from the start. The Adding time was the
- amount of time the application took to add the document to the queue and for
- the #Ready" flag to be produced in PCONSOLE. Observably, Adding times were
- longer for applications adding print jobs than for NPRINT to add to the
- queue. This made sense, since NPRINT sends already formatted
- printer#compatible output.
-
- We saw Adding time as a significant number for two other reasons. One, the
- first job in the queue would put its Adding time on in front of any other
- subsequently added job (that is, another job that is added before the first
- one clears or is sufficiently long to be adding when the first one is clear.
- Although different in detail, the instance looks much the same to the waiting
- users.) Two, different applications have different Adding times, but the
- Adding time becomes less significant as the job length increases.
-
- From our low#end study, we knew that the document type had a direct effect on
- the printer performance. In the area of high#end printing, we recognized that
- the document type would continue to have a marked effect on the queue Adding
- time and on the printer response time. We also knew that the printing port
- (parallel or serial) had some of the greatest effect upon printing
- performance. The questions we had were:
-
- w Will the limitations of the printing port dictate the amount of queue
- loading and (subsequently) the printing performance at the printer?
-
- w Will the printing rate from the queue to the printer be significantly
- high that jobs from the queue will drain out instead of build up?
-
- w Will the institution of alternate printers and services be necessary
- to maintain printing performance? These questions will have to be answered
- later.
-
- What we're ultimately aiming for is a formula or table which would be useful
- in predicting the time to receive print jobs in the high#end environment. At
- least this would be something to justify the purchase of another printer, and
- help in the future matter of how to maintain all of this as a LAN supervisor.
-
- Extended Print Service Performance Tests
-
- In designing our extended printing performance tests, we used two major
- operating systems: NetWare v2.2 and v3.11. The testing configurations were
- similar to the configurations tested in the low# end study, with the
- following differences:
-
-
- w the ports tested (only parallel, no serial)
-
- w the type of printers used (HPIII and HPIIIsi with its own network
- interface card)
-
- w the number of queues (some tests utilized two loaded queues)
-
- Basic Hardware Configuration
-
- shows our basic hardware configuration. As usual, all of the testing was
- done on thin Ethernet cable with NE2000 cards. Most of the testing revolved
- around manipulating the parameters and workloads in one configuration.
-
- : Basic Test Configuration
-
-
- What We Measured and Why
-
- In the testing regimen, our interest centered around times of delivery to
- anywhere and everywhere the print job was tracked before it was finished at
- the printer. Our interest in where the job went and how long it was there led
- us through the parts of NetWare printing we could measure and gave us some
- insight into what processes were taking how long in the printing environment.
-
- As mentioned before, we had decided to break the printing process into the
- major component parts that we could discriminate. From those we would try to
- discern what factors were pertinent in measuring the print services and which
- were extraneous.
-
- From , we were able to break print services into the following major
- components: Start time, Dwell time, Adding time, Activation time, Throughput
- time, Clear time, and Print time.
-
- Parameters for Calculation
-
- This section discusses derived values. The derived values are the result of
- subtracting the tn values discussed in the previous section. The resulting
- values have been assigned capital letters. The time formulas, or #T"
- formulas, provide us with several insights and a few questions which we do
- not have answers for yet.
-
- Start Time
-
- The first parameter is Start Time. In and of itself, it only marks the
- beginning of the test. However, it has become the basis by which we measure
- the absolute time of events on the printing side of the network.
-
- To = START TIME
- (2-7)
-
- Dwell Time
-
- The next item we will call Dwell time, until we come up with a more
- descriptive name. Dwell time is the interval between the start of a print job
- (user print initiation) and the time it actually starts being added to the
- queue. Note that we mean the time the Adding flag is set, not the time it
- actually appears in PCONSOLE. Ideally, this is what we would have liked to
- measure. But the lack of sophisticated#enough tools prevented it. What we
- measured was the time until the Adding flag appeared.
-
- T1 = DWELL TIME = t1 # t0
- (2-8)
-
- The value of Dwell time is that it tells us the amount of time between the
- user initiating printing to the network and the time for the network to
- initiate the response that says #OK, adding job XYZ." That also includes
- formatting time for the application.
-
- So what value is there in measuring the Dwell variable? Probably more than
- just how long you have to wait for the PCONSOLE #Adding" message to come on.
- Actually, it tells you a lot about the application's ability to print
- immediately or wait for other processes. On a busy network (85 percent
- utilization), Dwell time does not appear to take any longer than on a 30
- percent utilized network.
-
- That is one of the reasons we used NPRINT for our testing. It significantly
- reduced the wait for T1. (For now, Dwell time is a measurable number of
- questionable significance.)
-
- Adding Time
-
- Adding time is calculated in the same way as the Dwell time:
-
- T2 = ADDING TIME = t2 # t0
- (2-9)
-
- This is the time it takes to get the #Ready" message in PCONSOLE, and
- represents the amount of time for the application to send the formatted data
- to the queue.
-
- Activation Time
-
- The Activation time is how long it takes to get the #Active" flag from
- PCONSOLE. At this point, everything is in the print queue and the print
- service has gone active to the printer.
-
- T3 = ACTIVATION TIME = t3 # t0
- (2-10)
-
- Throughput Time
-
- One of the measurements taken which has not been evaluated thoroughly is the
- THRU time, the time for the first sheet to be printed.
-
- T4 = THRU TIME = t4 # t0
- (2-11)
-
- This is probably a misnomer and the selection of using the first sheet from
- the printer is probably a mistake. That will have to wait for another set of
- tests to verify. What it should have measured (and at this point probably
- does not) is the effect on the print service of utilizing PRINTCON and
- PRINTDEF. It might provide some insight into the performance activity
- relation with and without those utilities. For now, the data was sampled
- without PRINTCON or PRINTDEF.
-
- Clear Time
-
- Next is the #Clear" time, which we define as the disappearance of the
- #Active" message from PCONSOLE. Interestingly enough, in all cases this
- corresponded to the NEXT JOB time that we were trying to obtain as a
- different measurement. The #Active" message appeared for the next print job
- in the queue just as the last job cleared.
-
- T5 = CLEAR TIME = t5 # t0
- (2-12)
-
- Print Time
-
- The last measured time was when the final page of the print job came out of
- the printer. This Print time, as we dubbed it, was the time for the job to
- complete at the printer. T6 would be the time to use for calculating printing
- performance.
-
- T6 = PRINT TIME = t6 # t0
- (2-13)
-
- Observations and Test Conclusions
-
- The results of our extended print services tests are given in Appendix A. We
- had the opportunity to make several observations during our testing regimen.
- As observations, they have to be qualified as such. They are not necessarily
- tested results, and may prove completely erroneous.
-
- One of the most interesting things we observed during the printing tests was
- the server utilization. During the server loading tests for the HPIII using
- the parallel port, the server utilization normally went from 50 percent
- (loaded) to 85 percent and then varied from 67 percent to 92 percent for the
- remainder of the printing process. When the HPIIIsi was tested under the same
- conditions, the server utilization went to 85 percent momentarily, dropped
- back to 50 percent (the load factor) for most of the print job, increased
- briefly to 70 percent, then returned to 50 percent.
-
- We were looking for some simple time measurements that indicated print job
- transmission rates across the network. We found just those, but with an
- interesting twist. When the parallel port was being tested, we could see the
- transmission rate of the parallel port was definitely affecting the
- production rate so that nothing was going to the printer faster than 1,799
- bps. With the HPIIIsi, the transmission rate to the printer was higher.
-
- The results in show the comparison between NetWare v2.2 and v3.11 for
- parallel port HPIIIsi printing with regard to the t5 # t3 time. This brought
- up some question as to what effect replicating the experiment with a Graphics
- Only document would have, so we tested it as well.
-
- : Comparison of Rates with VAP and NLM
-
- Interestingly, the results for the HPIIIsi indicate that with the influence
- of the parallel port removed and the printer changed (between the HPIII and
- the HPIIIsi), the transmission rate from the queue to the paper was no longer
- a major limiting factor in print job production. A Graphics Only document
- moves through the queue almost as fast as a Text/Graphics document does.
-
- Implementation Considerations
-
- One of the major concerns in implementing extended print services is user
- convenience. The whole point of optimizing print services is to give the user
- as optimal a consideration as possible, while maintaining (if not optimizing)
- the ability to manage the activity and the network. Users bear the brunt of
- the work activity (#load"); the computer could care less. Over the years,
- users have increased their productivity, and now with the microcomputer being
- well established there is no reason to expect that productivity to decline.
- In fact, faster CPUs, better application software, and faster peripherals all
- precede an even greater surge in productivity. As we view users, we find that
- almost universally they become more proficient at whatever tasks they have.
- Printing is no exception. With all these increasingly productive software
- users printing, LAN services will have to improve. The areas of design,
- implementation, and supervision will all need sharper, faster tools.
-
- In the meantime, here are a few formulas which may not alter the shape of
- your LAN, but may provide just enough ammunition in the next planning meeting
- to get you the additional items you need.
-
- Calculating Average Queue Utilization
-
- One calculation that may prove very useful to the LAN supervisor is a simple
- but effective average of time the queue is utilized.
-
- T(App.Avg.(full)) + (N#1) T(Avg.
- Active)
- Avg. Printing Time = ---------------------------
- (2-14)
- N
-
- Note that (N#1), the number of people printing minus one, is not a subscript,
- but a multiplier.
-
- Here T(App.Avg.(full)) is equal to the average measured full time for an
- application to print through to the printer (assuming no queue priorities
- have been set). It must take into account all the types of print jobs that
- different types of users may send to that queue. If you want to determine
- this number, get a sampling of the documents used by a queue's workgroup for
- that queue specifically and print them out, one at a time. Then take the
- average.
-
- The result in formula 2-14 is the average time to complete printing for all
- of the users in a queue. You can expend a lot of work in determining this
- number, especially if individuals in the queue workgroup or queue#group are
- highly heterogeneous in their printing. But the result, especially for peak
- period printing, is extremely useful. It can tell you approximately how long
- the last person will wait for a print job in peak periods.
-
- It is up to the LAN supervisor or print manager to get with the users and
- work out a solution if this time is too long. How long is too long is
- something you will have to work out within your own workgroups and budget
- constraints. However, it does present the necessity for exploring some of the
- alternatives in print service design. Options you may wish to explore
- include:
-
- w multiple queues
-
- w multiple (existing or new) printers to a queue with user notification
-
-
- w high speed printers
-
- w consolidating several queues
-
- w changing the physical design of the printing workgroups
-
- Probability Modeling
-
- The next activity that may be of interest is calculating the probability of
- getting your own job through in a period of time. Using a typical example
- such as ten people, each with five print jobs to do by noon, usually gives
- the wrong result. This oversimplification does not take into consideration
- that the five print jobs are six#page contracts, that they are in revision
- two times, that they are printed for the individual with each revision, and
- that they all have to go out by noon. What this means is ten people will be
- printing those jobs twice between 11:00 a.m. and 11:45 a.m. That's 100 print
- jobs (fancifully the short ones are one page long) all to be printed in 45
- minutes.
-
- Now suppose the print jobs are real estate letters and each one of them
- contains a graphic. It's going to take the ten users 1 second each to begin
- the printing cycle; unfortunately only one user can be first. The other nine
- will get their jobs in after the lucky first user. Several people are going
- to have to wait; the only question is who and for how long.
-
- Regarding the #who" question, you can always set the queue priority for
- several queues talking to one printer. This lets you get the chief
- executive's print job scheduled as number 2 with multiple queues to one
- printer, even when the job is sent as number 6.
-
- Having several queues talking to one printer gives our average time formula a
- bit of a twist, because the number N in the formula now has to take into
- consideration all of the queue#groups that talk to one printer.
-
- N = n (queue group #1) + ... + n (queue group #N)
- (2-15)
-
- With this value for N, it should not take longer for the last job to be
- printed than the average print time multiplied by the number of users.
-
- T(App.Avg.(full)) + (N#1) T(Avg. Active)
- Avg. Printing Time = ----------------------------
- (2-16) N
-
- For peak period printing with printer contention from other queue#groups, the
- probability model for the priority 2 queue with a priority 1 queue attached
- begins to look like:
-
- (T(App.Avg.(full)) + T(Avg. Active Queue1)) x (N-2) +
- T(Avg. Active Queue2)
- Avg. Printing Time = ---------------------------------------------------
- (2-17)
- NToT
-
- For periods with no contention, it looks like:
-
- Avg. Printing Time = T(App. Avg. (full) Queue2)
- (2-18)
-
- Normally it should not take longer than the above average time for the
- non#priority job to get through the printer.
-
- Of course, you can take this type of modeling beyond its useful boundaries,
- but figuring your average print time does provide the groundwork for a
- discussion on when new printers may need to be added and what queues will
- have priority over the others.
-
- Appendix A: Test Results for Extended Print Services
-
- The following table lists the times recorded during the extended print
- service tests. The absolute times (ABS) indicate cumulative time from the
- initiation of the print job. The delta times represent the difference between
- each discrete measurement. For an explanation of the numbers in the #Test
- Config" column, see Appendix B.
-
- TEST ABS... DELTA. ABS... DELTA. ABS... DELTA. ABS... DELTA. ABS...
- DELTA. ABS... DELTA.
- CONFIG T1 T1 T2 T2 T3 T3 T4 T4 T5 T5
- T6 T6
- (Sec.) (Sec.) (Sec.) (Sec.) (Sec.) (Sec.) (Sec.) (Sec.) (Sec.)
- (Sec.) (Sec.) (Sec.)
- ______ ______ ______ ______ ______ ______ ______ ______ ______
- ______ ______ ______
-
-
- 19 3 3 8 5 12 4 35 23 53
- 41 70 17
- 19 5 5 10 5 12 2 30 18 50
- 38 59 9
- 19 2 2 7 5 22 15 43 21 62
- 40 71 9
-
- 20 3 3 8 5 9 1 28 19 48
- 39 58 10
- 20 7 7 12 5 17 5 41 24 56
- 39 69 13
- 20 4 4 8 4 18 10 41 23 59
- 41 70 11
-
- 21 5 5 9 4 11 2 34 23 50
- 39 63 13
- 21 5 5 6 1 11 5 34 23 50
- 39 62 12
- 21 4 4 6 2 10 4 25 15 44
- 34 55 11
-
- 22 3 3 8 5 18 10 64 46 64
- 46 77 13
- 22 5 5 10 5 15 5 39 24 55
- 40 65 10
- 22 4 4 5 1 19 14 42 23 59
- 40 70 11
-
- 23 6 6 8 2 21 13 83 62 216
- 195 235 19
- 23 5 5 7 2 17 10 101 84 197
- 180 217 20
- 23 3 3 3 0 14 11 76 62 209
- 195 229 20
-
- 26 4 4 9 5 10 1 99 89 214
- 204 215 1
- 26 3 3 9 6 14 5 60 46 194
- 180 213 19
- 26 3 3 7 4 18 11 75 57 214
- 196 231 17
-
- 27 3 3 8 5 18 10 69 51 168
- 150 187 19
- 27 4 4 4 0 37 33 75 38 187
- 150 204 17
- 27 4 4 4 0 15 11 72 57 178
- 163 201 23
-
- 31 2 2 10 8 12 2 31 19 41
- 29 54 13
- 31 5 5 5 0 6 1 28 22 40
- 34 53 13
- 31 1 1 8 7 8 0 28 20 41
- 33 51 10
-
- 34 2 2 7 5 17 10 38 21 47
- 30 61 14
-
- 35 2 2 3 1 12 9 32 20 34
- 22 46 12
- 35 2 2 7 5 17 10 32 15 33
- 16 47 14
- 35 5 5 6 1 10 4 25 15 25
- 15 38 13
-
- Appendix B: High#End Test Configurations
-
- This appendix details the hardware and software configurations (numbered 19
- through 35) used for the extended print service performance tests. These are
- the numbers indicated in the #Test Config" column in Appendix A.
-
-
-
- Printer
- DOCUMENT
-
-
-
- N0. Type Config OS QUEUES LOAD PSERVER VERSION Size Type
- METHOD
-
-
-
- 19 HPIIIsi F/S 2.2 1 U VAP V1.21
- 270451 T/G NPRINT
-
- 20 HPIIIsi F/S 2.2 2 U VAP V1.21 270451 T/G
- NPRINT
-
- 21 HPIIIsi F/S 2.2 2 L VAP V1.21 270451 T/G
- NPRINT
-
- 22 HPIIIsi F/S 2.2 1 L VAP V1.21 270451 T/G
- NPRINT
-
- 23 HPIII F/S 2.2 1 U VAP V1.21 270451 T/G
- NPRINT
-
- 24 HPIII F/S 2.2 2 U VAP V1.21 270451 T/G
- NPRINT
-
- 25 HPIII F/S 2.2 2 L VAP V1.21 270451 T/G
- NPRINT
-
- 26 HPIII F/S 2.2 1 L VAP V1.21 270451 T/G
- NPRINT
-
- 27 HPIII F/S 3.1 1 U NLM V1.21
- 270451 T/G NPRINT
-
- 28 HPIII F/S 3.1 1 L NLM V1.21 270451 T/G
- NPRINT
-
- 29 HPIII F/S 3.1 2 L NLM V1.21 270451 T/G
- NPRINT
-
- 30 HPIII F/S 3.1 2 U NLM V1.21 270451 T/G
- NPRINT
-
- 31 HPIIIsi F/S 3.1 1 U NLM V1.21
- 270451 T/G NPRINT
-
- 32 HPIIIsi F/S 3.1 1 L NLM V1.21
- 270451 T/G NPRINT
-
- 33 HPIIIsi F/S 3.1 2 L NLM V1.21
- 270451 T/G NPRINT
-
- 34 HPIIIsi F/S 3.1 2 U NLM V1.21
- 270451 T/G NPRINT
-
- 35 HPIIIsi F/S 3.1 1 U NLM 1.21 150807 G/0
- NPRINT
-
- Editor's Note: The author accepts written feedback at FAX (801) 429#5511.
-
-