Workload Description
The warehouse and inventory control (WIC) workload is a transaction processing program based on the on-line support required to manage the movement of i tems into and out of a ware house . Although WIC is a warehouse app.lica-
� :::J 0 I ;n [!J 0 2 1- :::J Q_ I C) :::J 0 a: I 1- 30 25 20 1 5 1 0 5 1 0 20 30 40 NUMBER OF STREAMS KEY: .A. 8978 MEASUREMENT v 8974 MEASUR EMENT • 8700 MEASUREMENT • 8978 SIMU LATION 0 8974 SIMULATION 0 8700 SIMU LATION 50
Figure 5 GAUSSIAN 82 Throughput Model versus Measured
Digital Tech11ical]ournal
No. 5 September 1987
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tion , it is a representative transaction processing application.
A WIC workload is divided into five functional parts, each associated with one task type. The five task types and the percent of total tasks rep resented by each type are given as follows: • Receiving - Performs the functions needed to
log the receipt of parts from the loading dock i nto the warehouse ( 1 7 percent)
• Inventory - Queries and u pdates the files conta ining inventory i nformation ( 1 0 per cent)
• Warehouse - Performs the functions needed
to pick parts based on se leered orders ( 1 0 per cent)
• Order entry - Places orders to be fi lled by the warehouse ( 46 percent)
• Purchase order - Composes purchase orders (with outside vendors) for parts to be stocked in the warehouse ( 1 7 percent)
Each task is performed a specified proportion of the execution time. The task selection percent ages reflect the assu mption that the average flow of i tems into the warehouse equals the flow out of the warehouse during peak-hour operations.
Each task consists of a nu mber of transactions. A transaction is defined as one or more user input steps followed by computation , database I/0, and output to the terminal user. Each task has an aver age of 7 . 8 transactions in the WIC app.lication . Since a transaction implies the initiation of work by the system , throughput is measured in terms of transactions per second .
Al l menus and forms are implemented by re quests to the VAX Transaction Data Management System. Inqu i ry and update operations take p lace on seven different application fi les i n the VAX Record Management Services ( RMS) software.
Performance Metrics for WIC Workload • System throughput is defined as the total num
ber of transaction processed systemwide i n constant time (one second) , o r transactions per second (TPS) . This number i ncludes all types of transactions . Figure 6 i ll ustrates the user and system actions needed for one trans action .
• User prod uctivity is the average number of
transactions each user completes i n a unit of time, expressed in transactions per user per hour.
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VAXcluster Systems
System Level Performance of VAX 8974 and 8978 Systems USER THINKING TIME USER PR ESSES CARRIAGE RETURN USER TYPING TIME SYSTEM BEGINS RESPONSE SYSTEM COMPLETES RESPONSE - sERVICE TIME- TRANSACTION Figure 6 Transaction
• Mean service ti me is defined as the average time required to complete a transaction . This time does not i nclude the input typing time or think time, but does include the time taken for screen output. A specific receiving transac tion, called REC3, was chosen for the evalua tion of this metric . REC3 i nvolves updating three records and writing one record several times, which represents a moderately complex unit of work.
Test Methodology
The transaction processing environment was cre ated by using remote terminal emulators (RTEs) , which emulated all activities of terminal users. The RTEs also kept track of each transaction and the time of i ts occurrence and maintained the transaction mix throughout the experiment. Sev eral systems of the VAX 8600 cl ass were used as RTEs to load the systems under test, called SUTs.
To establish a base level of performance, the initial set of experi ments was carried out with one VAX 8700 CPU as the SUT. The VAX 8974 and VAX 8978 systems were then tested by vary ing the number of users, and hence the number of transactions.
The RTEs logged users i nto the SUTs in the cluster at four-second i ntervals (users were evenly distributed between the SUTs i n the clus ter for all the configurations tested) . After log ging in, each user started his application , also at four-second i ntervals. After the SUTs reached a steady state, data was collected for 2 0 m i nutes on both the SUTs and the RTEs.
Hardware and Software Configuration The hardware environment for each VAXcluster configuration included the same 1/0 subsystem . The hardware components of the configurations consisted of the fol lowing elements:
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• A VAX 8974 system with four VAX 8700 CPUs, each with 3 2 MB of memory, two HSC70 con trol lers, one SA4 8 2 storage array for the sys tem ; and the pagingjswapping software, and three SA4 82 arrays for the database.
• A VAX 8978 system with eight VAX 8700 CPUs; the other hardware was the same as the VAX 8974 system 's above.
The software environment consisted of the VAXjVMS version 4 . 5 operating system , VAX- 1 1 ACMS version 2 . 0, VAX- 1 1 TDMS version 1 .4 , VAX- 1 1 CDD version 3 . 1 , VAX- 1 1 COBOL ver sion 3 . 1 , and SPM version 3 0 .
In addition t o the general tuning of the SYSGEN parameters, several appl ication-specific parame ters were adjusted for the best performance . These include the number of appl ication server processes, and the size of the RMS global buffer used to buffer some portion of each RMS fi le. In a distributed system l i ke a cluster, increasing the buffer size can resul t in additional 1/0 requests caused by more frequent buffer invalidations. The database consisted of 1 4 RMS indexed sequential files spread over 1 2 disk spindles to balance the 1/0 rates.
Performance Results and Observatio ns
System Throughput
Figure 7 displays the system throughput (the nu mber of exchanges processed) at different user loads on the different configurations. These curves give a global i ndication of the overal l rela tive performance of the VAX 8974 and VAX 8978 systems. 0 60 z 0 u 50 UJ (/) cr 40 UJ a._ (/) 30 z 0 20 f= u <( 1 0 (/) z <( cr 1- 200 400 600 800 1 000 1 200 1 400 K E Y : 0 VAX 8978 .6. VAX 8974 1:> VAX 8700 N U M B E R OF USERS
Figure 7 WIC Throughput
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