Collaborative Lifecycle Management performance report: RDNG 5.0

Introduction

This report compares the performance of Rational DOORS Next Generation (RDNG) version 5.0 to the previous Rational Requirements Composer (RRC) version 4.0.6 release. The test objective is achieved in three steps:

• Run version 4.0.6 with standard 1.5 hour test using 400 concurrent users.
• Run version 5.0 with standard 1.5 hour test using 400 concurrent users.
• The test is run three times for each version and the resulting six tests are compared with each other. Three tests per version is used to get a more accurate picture since there are variations expected between runs.

Disclaimer

The information in this document is distributed AS IS. The use of this information or the implementation of any of these techniques is a customer responsibility and depends on the customer’s ability to evaluate and integrate them into the customer’s operational environment. While each item may have been reviewed by IBM for accuracy in a specific situation, there is no guarantee that the same or similar results will be obtained elsewhere. Customers attempting to adapt these techniques to their own environments do so at their own risk. Any pointers in this publication to external Web sites are provided for convenience only and do not in any manner serve as an endorsement of these Web sites. Any performance data contained in this document was determined in a controlled environment, and therefore, the results that may be obtained in other operating environments may vary significantly. Users of this document should verify the applicable data for their specific environment.

Performance is based on measurements and projections using standard IBM benchmarks in a controlled environment. The actual throughput or performance that any user will experience will vary depending upon many factors, including considerations such as the amount of multi-programming in the user’s job stream, the I/O configuration, the storage configuration, and the workload processed. Therefore, no assurance can be given that an individual user will achieve results similar to those stated here.

This testing was done as a way to compare and characterize the differences in performance between different versions of the product. The results shown here should thus be looked at as a comparison of the contrasting performance between different versions, and not as an absolute benchmark of performance.

What our tests measure

We use predominantly automated tooling such as Rational Performance Tester (RPT) to simulate a workload normally generated by client software such as the Eclipse client or web browsers. All response times listed are those measured by our automated tooling and not a client.

The diagram below describes at a very high level which aspects of the entire end-to-end experience (human end-user to server and back again) that our performance tests simulate. The tests described in this article simulate a large part of the end-to-end transaction as indicated. Performance tests include some simulation of browser rendering and network latency between the simulated browser client and the application server stack.

Findings

Performance goals

• Verify that there are no performance regressions between current release and prior release with 400 concurrent users using the workload described below.
  • When comparing the three 5.0 runs with the three 4.0.6 runs the average of the three runs is used for comparison. Generally a 10% difference is accepted.

Findings

• Performance
  • Several of the user actions, such as opening a project, have improved performance.
  • There is a performance regression defect open that will negatively impact the time it will take to create reports.

• Impact by separating the RDNG repository from the JTS repository.
  • This change has not negatively impacted performance.
  • As expected this change has increased the workload for the RDNG application while it has lessened the workload for JTS.
    • The impact can be seen in higher CPU and memory utilization by the RDNG server and a corresponding lesser utilization by JTS
  • Note that it is now possible to have more than one RDNG server using the same JTS. This will allow scaling flexibility by adding additional RDNG servers.

• Other observations
  • RDNG now maintains its own indices. Ensure that there is enough disk space to accommodate the indices on the RDNG server.
    • In our test environment the RDNG indices created for a 240,000 artifact repository required 17.6 GB of disk space. Note that the new RDNG indices require more disk space than previously used by JTS 4.0.6 using the same data. In our test environment RDNG required 50% more disk space for indices.
    • Putting the indices on a faster drive will improve performance.
  • When upgrading from a previous version the JTS database will be cloned. This will require additional resources such as disk space and memory.
    • Over time migrated data that is not required will be removed but initially the new RDNG database created will double the required disk space.
    • Additional memory requirements by the database will depend on database vendor and configuration. It is strongly recommended to test thoroughly in a test environment before upgrading.

Topology

The topology under test is based on Standard Topology (E1) Enterprise - Distributed / Linux / DB2.

The specifications of machines under test are listed in the table below. Server tuning details listed in Appendix A

Network connectivity

All server machines and test clients are located on the same subnet. The LAN has 1000 Mbps of maximum bandwidth and less than 0.3ms latency in ping.

Data volume and shape

The artifacts were distributed between 10 projects for a total of 240,659 artifacts.

The repository contained the following data:

• 219 modules
• 218,632 module artifacts
• 22,027 requirement artifacts
• 11,715 folders
• 150 collections
• 704 reviews
• 114,258 comments
• 3000 public tags
• 500 private tags
• 2,374 terms
• 75,941 links
• 2000 views

• 4.0.6
• Database size on disk = 20 GB
• JTS index size on disk = 11.5 GB

• 5.0
• JTS database size on disk = 20 GB (initial size before database cleanup has completed)
• RM database size on disk = 20 GB (initial size before database cleanup has completed)
• JTS index size on disk = 1.6 GB
• RM index size on disk = 17.3 GB

The large project contained the following data:

• 22 modules
• 1,170 folders
• 2,171 requirement artifacts
• 20,600 module artifacts
• 15 collections
• 62 reviews
• 11,350 comments
• 300 public tags
• 50 private tags
• 132 terms
• 7,676 links

Methodology

Rational Performance Tester was used to simulate the workload created using the web client. Each user completed a random use case from a set of available use cases. A Rational Performance Tester script is created for each use case. The scripts are organized by pages and each page represents a user action.

Based on real customer use, the test scenario provides a ratio of 70% reads and 30% writes. The users completed use cases at a rate of 30 pages per hour per user. Each performance test runs for 90 minutes after all of the users are activated in the system.

Test cases and workload characterization

Response time comparison

The median response time provided more even results than the average response time. The nature of the high variance between tests where some tasks at time takes a longer time to run, such as when the server is under heavy load, makes the average response time less predictive. Both the median and average values are included in the following tables and charts for comparison.

In the repository that contained 240,000 artifacts with 400 concurrent users, no obvious regression was shown when comparing response times between runs.

The numbers in the following charts include all of the pages for all of the scripts that ran.

Results

Observation

• In 5.0 RDNG is utilizing its own repository instead of sharing it with JTS. Both memory and CPU utilization reflect the changed work distribution in 5.0 where RDNG is managing its own repository.
• Note that additional memory is used by the DB2 server due to the additional database required by RDNG 5.0.

Garbage collection

Verbose garbage collection is enabled to create the GC logs. The GC logs show very little variation between runs. The difference between version 4.0.6 and 5.0 displayed by the GC logs reflect the additional work performed by RDNG 5.0 that was previously done by JTS . Below is an example of the output from the GC log for JTS and RDNG, including both versions 4.0.6 and 5.0 for each application server.

RM

• Observation: The graphs reflect the change in workload now when the RDNG application is performing all RDNG related tasks. In 4.0.6 queries and other database related interactions were done by JTS as the owner of the repository.
• RM 4.0.6

• RM 5.0

JTS

• Observation: The graphs reflect the change in workload now when the JTS application is not performing some of the RM related repository tasks. In RM 4.0.6 database related queries were done by JTS.
• JTS 4.0.6

• JTS 5.0

Create a collection

• Observation: All gestures, except open the project, show between 10 - 15% faster execution

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Filter a query

• Observation: Opening a project has a noticeable performance improvement as can be seen in several of the following graphs.

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Open nested folders

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Manage folders

• Observation: The create a folder gesture is on average 24% faster. More noticeable is the difference when moving a folder, a 35% improvement.

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Query by ID

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View collections

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Check suspect links

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Create a multi-value artifact

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Create an artifact

• Observation: Open the create artifact dialog box is 29% faster. Specify options for the new artifact is 22% faster. Open artifact improved with 13%.

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Show artifacts in a Tree view

• Observation: Open a folder that contains artifacts with links is 35% faster.

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Open graphical artifacts

• Observation: Open a sketch and open a use case are both in average 15% faster in 5.0.

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Create and edit a storyboard

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Display the hover information for a collection

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Query by string

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Create a PDF report

• Observation: The last step of creating a report is slower in 5.0. The root cause for this performance regression is still under investigation and a fix would be delivered to a future release (see work item (xxxxxx))

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Create a Microsoft Word report

• Observation: The last step of creating a report is slower in 5.0. The root cause for this performance regression is still under investigation and a fix would be delivered to a future release (see work item (xxxxxx))

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Browse project folder

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Open collection and display first page

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Create artifact in large module

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Display module history

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Create traceability report using 50 artifact

• Observation: The last step of creating a report is slower in 5.0. The root cause for this performance regression is still under investigation and a fix would be delivered to a future release (see work item (xxxxxx))

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Open large module

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Scroll through a large module

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Switch between modules

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Edit a module artifact

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Save a module

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Create a large module report

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Uploading 4 MB file in new artifact

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Switch view

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Hover over linked artifact

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Appendix A

-XX:MaxDirectMemorySize=2g -Xgcpolicy:gencon -Xmx8g -Xms8g -Xmn2g -Xcompressedrefs -Xgc:preferredHeapBase=0x100000000 -Xverbosegclog:logs/gc.log

For more information

• Collaborative Lifecycle Management 2012 Sizing Report (Standard Topology E1)

About the authors

GustafSvensson

Questions and comments:

• What other performance information would you like to see here?
• Do you have performance scenarios to share?
• Do you have scenarios that are not addressed in documentation?
• Where are you having problems in performance?

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