Performance Testing Tools Jan Bartoň 30/10/2003

CESNET technical report number 18/2003 Performance Testing Tools Jan Bartoň 30/10/2003

1 Abstract

The report describes properties and abilities of software tools for performance testing. It also shows the tools comparison according to requirements for testing tools described in RFC 2544 (Benchmarking Terminology for Network Intercon- nection Devices).

2 Introduction

This report is intended as a basic documentation for auxiliary utilities or programs that have been made for the purposes of evaluating transfer performance between one or more PCs in the role of traffic generators and another one on the receiving side. Section 3 3 describes requirements for software testing tools according to RFC 2544. Available tools for performance testing are catalogued by this document in section 4 4. This section also shows the testing tools compatibility with RFC 2544 and the evaluation of IPv6 support. The summary of supported requirements for testing tools and IPv6 support can be seen in section 5 5.

3 Requirements for software performance testing tools according to RFC-2544

3.1 User defined frame format Testing tool should be able to use test frame formats defined in RFC 2544 - Appendix C: Test Frame Formats. These exact frame formats should be used for specific protocol/media combination (ex. IP/Ethernet) and for testing other media combinations as a template. The frame size should be variable, so that we can determine a full characterization of the DUT (Device Under Test) performance. It might be useful to know the DUT performance under a number of conditions, so we need to place some special frames into a normal test frames stream (ex. broadcast, management, routing update frames . . . ). These modifiers could have a significant impact on an ability of a router to forward data frames. The testing tool should be able to use a random destination address to simulate multiple streams of data. For more details about recommended frame formats see Appendix C included with RFC 2544.

3.2 Verifying received frames The receiver should discard any frames received during a test run that are not actual forwarded test frames (ex. management frames, routing update frames . . . ). It should verify the length of received frames and report the number of dropped, duplicated frames, frames that were received out of order and the number of gaps in the received frame numbering sequence. The testing tool should verify that the all of the routing updates (see above in section User defined frame format) were processed by the DUT.

3.3 Bidirectional traffic Real network traffic is not in a single direction. To test the bidirectional performance of a DUT, we need a testing tool, which can be run with the same data rate in each direction. The sum of the data rates should not exceed the theoretical limit for the media.

3.4 Setting inter-frame time gap All the tests should be performed with both steady state traffic and with traffic consisting of repeated bursts of frames. Because of needs to determine the minimum interval between bursts, which the DUT can process with no frame loss, we need to set the inter-frame time gap between defined frames (bursts).

4 Tools

Each tool is defined as follows: Description A description of the tools construction, and the implementation methodology of the tests. Automation What steps are required to complete the test? What human intervention is required?

CESNET technical report number 18/2003 2 Settings possibilities Summary of program settings possibilities. Availability How do you retrieve this tool and get more information about it? Required Environment Compilers, OS version, etc. required to build and/or run the associated tool. RFC 2544 compatibility Summary of requirements to testing tools according to RFC 2544 as defined in section 3 3. References A list of publications relating to the tool, if any.

4.1 DBS 1.1.5 4.1.1 Description DBS (Distributed Benchmark System) is aiming to give performance index with multi-point configuration and also in order to measure changes of throughput. It measures the performance of entire TCP functions in various operational environments. DBS has the capability of both measuring and analyzing TCP performance more in details. DBS is able to evaluate the three TCP control mechanisms - flow control, retransmission control and congestion avoidance control. The DBS can generate various situations where the three controls are working together. The DBS can also generate UDP traffic for more realistic benchmarking.

Figure 1: DBS architecture

CESNET technical report number 18/2003 3 The DBS is composed of three programs. Figure shows an overview of the DBS System Structure. The dbsc is a control program to handle monitoring program launched on observed hosts. dbsd is a program for sending and receiving data among observed hosts. These two programs are used for actual benchmarking. The dbs view is used for data analysis. The details of these programs are described below:

dbsc: DBS controller (Controlling Host)

The DBS controller is a program controlling the experiment of TCP/UDP data transfer. Controller reads commands from a command file, then it asks the DBS daemons to start data transfer experiments, and after receiving results from the daemons, the DBS controller saves them into the local files.

dbsd: DBS daemon (Measuring Host)

The DBS daemon is a daemon program that is launched on the experimen- tal hosts. It sends and receives network traffic according to the commands instructed by the DBS controller.

dbs view: DBS viewer

The DBS viewer is a program for analysis data which is gathered by the DBS controller. It draws graphs to reveal the transitions of sequence numbers, changes of throughput, changes of delay times or other performance indexes. If measuring host has only one network interface card, traffic of command/result and measured traffic are transferred on the same network. This may influence the measurement results. To avoid this influence, DBS controls command/result and measured traffic are not transferred at the same time. DBS implementation assumes that clocks on all the hosts participating to the benchmark are synchronized.

4.1.2 Automation Commands of execution are driven by a command file. Format of the command file is as follows. When multiple data streams are transferred in the same test, many configurations should be written in the same file.

# First Configuration { sender {’configurations of sender’; ’sending traffic pattern {s}’;} receiver {’configurations of receiver’;’receiving message pattern {s}’;} ’configuration of the connection’; }

CESNET technical report number 18/2003 4 # Second Configuration { sender {’configurations of sender’; ’sending traffic pattern {s}’;} receiver {’configurations of receiver’;’receiving message pattern {s}’;} ’configuration of the connection’; } . . .

Format of ’sending traffic pattern s’

pattern { data size, message size, interval, wait time; data size, message size, interval, wait time; . . . ; }

Figure 2: Patern parameters meaning

The traffic is modeled as a sequence of data chunks called ”frames”. The size of each frame may vary. Each frame may consist of several messages. A single message is defined that it can be transferred in a single UDP datagram. If a frame is longer than the UDP maximum transfer unit (64KB), the frame is split into several messages. Between frames, there is a time gap called ”wait time” which implies the application overhead. The preparation time of each frame can be treated as this wait time. Moreover, this model controls the frame intervals. This frame interval can be used for modeling of an application level rate control. Command File Sample

CESNET technical report number 18/2003 5 # Sample file { sender { hostname = host1; port = 0; send_buff = 65535; recv_buff = 65535; mem_align = 2048; pattern {2048, 2048, 0.0, 0.0} }

receiver { hostname = host2; port = 20001; recv_buff = 65535; send_buff = 65535; mem_align = 2048; pattern {2048, 2048, 0.0, 0.0} }

file = test1; protocol = TCP; start_time = 0.0; end_time = 30; send_times = 2048; }

See http://www.kusa.ac.jp/ yukio-m/dbs/dbs man.html for more information about constructing command file.

4.1.3 Settings possibilities

send/receive buffer size modification

setting the TCP no delay option

specify the starting time of data transfer for each connection

specify frame size and inter-frame time gap

specify test duration

sending complicated traffic patterns

CESNET technical report number 18/2003 6 Through ”tcp trace” function, several TCP internal information such as TCP/IP pseudo-headers, TCP congestion window size, round trip time, retransmission timeout and other values in the TCB structure can be obtained.

4.1.4 Availability See http://www.ai3.net/products/dbs1 for details of precise OS versions supported, and for download of the source code. Current implementation supports BSDI BSD/OS, FreeBSD, NetBSD, Linux, mkLinux, SunOS, IRIX, Ultrix, Digital UNIX, NEWS OS, HP-UX.

4.1.5 Required Environment C language compiler, UNIX-style socket API support.

4.1.6 RFC 2544 compatibility

User defined frame format No Support Verifying received frames Checks only sequence numbers of received frames. Bidirectional traffic It could be made of two single traffics between specified hosts running at the same time in the opposite direction. Setting inter-frame time gap Full Support

4.1.7 References Performance and Control of Network Systems, Proceedings of SPIE, Volume 3231, November 1997(English) ”DBS: a powerful tool for TCP performance evaluations”2 Informating Processing Society of Japan, DPS, 95-DPS-71, July 1995 (Japanese) ”A proposal of DBS: performance evaluation for TCP over multipoint connection”3 Internet Conference’ 96, July 1996 (Japanese) ”Design and Implementation of DBS: a performance evaluation system for TCP”4

1http://www.ai3.net/products/dbs 2http://www.kusa.ac.jp/ yukio-m/papers/dbs paper.ps 3http://www.kusa.ac.jp/ yukio-m/papers/dps9507.ps 4http://www.kusa.ac.jp/ yukio-m/papers/conf96.ps

CESNET technical report number 18/2003 7 Master’s Thesis, Graduate School of Information Science, Nara Institute of Sci- ence and Technology, March 7, 1996 (Japanese) ”Design and Implementation of DBS: a performance evaluation system for multipoint TCP connections”5 ”Digest of Master’s Thesis”6

4.2 IPerf 1.7.0 4.2.1 Description IPerf is a ttcp like tool with considerable advantages over it. Using a client- server model to determine maximum bandwidth you can also measure delay jitter, packet loss, determine MTU, support TCP window size, run tests by amount transferred or for a specified period of time. Server can handle multiple simultaneous connections. Client can create UDP streams of specified bandwidth. Client-server model can use for testing bidirectional mode called ”dual testing mode”. IPerf uses representative streams to test out how link layer compression affects your achievable bandwidth and prints periodic intermediate bandwidth, jitter, and loss reports at specified intervals. As one of the few also supports IPv6.

4.2.2 Automation It is command-line driven. Use the -D command line option to run the server as a daemon and redirect the output to a file. E.g. iperf -s -D > iperfLog. Command line samples:

node2> iperf -s -u -l 32k -w 128k -i 1

-s = run IPerf in server mode

-u = use UDP instead TCP

-l 32k = buffer length

-w 128k = largest receivable datagram size

-i 1 = interval time in seconds between periodic reports

node1> iperf -c node2 -b 10m -l 32k -w 128k

5http://www.kusa.ac.jp/ yukio-m/papers/mthesis.ps 6http://www.kusa.ac.jp/ yukio-m/papers/mthesis digest.ps

CESNET technical report number 18/2003 8 -c = run IPerf in client mode

node2 = server address

-b 10m = UDP bandwidth to send at, in bits/sec - 10Mbit/sec

4.2.3 Settings possibilities

send/receive buffer size modification

specify TCP maximum segment size

setting the TCP No Delay option

UDP server provides multicast mode

bidirectional testing mode

tradeoff testing mode (request/response test)

setting the number of simultaneous connections to make to the server (requires thread support on both the client and server)

specify the type-of-service (as defined in RFC 1349) for outgoing packets

specify the time-to-live for outgoing multicast packets

use a representative stream (from file or stdin) to measure bandwidth

specify test duration

4.2.4 Availability Iperf is released as a distribution of the C++ source. Pre-compiled binaries for selected operating systems are also available (Linux, FreeBSD, IRIX, MacOS, MS Windows, OpenBSD, Solaris). See http://dast.nlanr.net/Projects/Iperf/7 for more information about program, for details of precise OS versions supported, and for download of the source code.

4.2.5 Required Environment C++ non cross-compiler

7http://dast.nlanr.net/Projects/Iperf/

CESNET technical report number 18/2003 9 4.2.6 RFC 2544 compatibility

User defined frame format Iperf can specify only data content of UDP packet in frame definition. Verifying received frames It determines packet loss only. Bidirectional traffic Full Support Setting inter-frame time gap No Support

4.3 NetPerf 2.2pl4 4.3.1 Description NetPerf is a benchmark that can be used to measure the performance of many different types of networking. It provides tests for both unidirectional throughput and end-to-end latency. It also includes provisions for CPU utilization measurement. Its primary focus is on bulk data transfer and request/response performance using either TCP or UDP and the BSD Sockets interface. There are optional tests available to measure the performance of DLPI, Unix Domain Sockets, the Fore ATM API and the HP HiPPI LLA interface. NetPerf is designed around the basic client-server model. There are two programs - netperf and netserver. The first thing after running program is establishing a control connection. This connection is used to pass test configuration information and results to and from remote system. After this process is established new connection - measurement connection. The test is performed and the results are displayed. NetPerf places no traffic on the control connection while a test is in progress. NetPerf provides three types of transfers: Bulk Data Transfer - also referred to as ”stream” or ”unidirectional stream”. This test measures how fast one system can send data to another and/or how fast that other system can receive it. Request/Response Transfer - request/response performance is quoted as ”trans- actions/sec” for a given request and response size. A transaction is defined as the exchange of a single request and a single response. Connect/Request/Response - instead of simply measuring the performance of request/response in the same connection, it establishes a new connection for each request/response pair.

CESNET technical report number 18/2003 10 NetPerf includes test which use a socket interface to IPv6, but the control connection remains IPv4.

4.3.2 Automation

Execution as child of inetd requires editing of /etc/services and /etc/inetd.conf. To assist in measuring, script files are provided with the NetPerf distribution (script for measuring stream performance, script for measuring request/response performance ...). NetPerf is command-line driven. Command line samples:

node1> netserver -p 20000 -n 2

-p = listen on the specified port

-n = number of CPU’s in the system

node2> netperf -t TCP_STREAM -H node1 -- -s 16384 -S 16K

-t = test name to perform (script filename)

-H = name of the remote system

-s = local send and receive socket buffer size

-S = the same as -s, but for remote system

4.3.3 Settings possibilities

send/receive buffer size modification of both systems (local/remote)

setting TCP No Delay option

setting the size of a burst of packets (used to pace the send rate when is no flow control provided by the protocol being measured)

specify test duration

pre-fill buffers with data from file

CPU rate calibration

CESNET technical report number 18/2003 11 4.3.4 Availability See http://www.netperf.org/netperf/NetperfPage.html 8 for more details or email Rick Jones ([email protected]). Binaries are available here for HP/UX Irix, Solaris, and Win32.

4.3.5 Required Environment C language compiler, sockets.

4.3.6 RFC 2544 compatibility

User defined frame format NetPerf can only specify data content of UDP packet in frame definition. Verifying received frames No Support Bidirectional traffic No Support Setting inter-frame time gap Full Support

4.4 NetPIPE 3.3 4.4.1 Description NetPIPE (Network Protocol Independent Performance Evaluator) is a protocol independent performance tool for comparing different networks and protocols. NetPIPE performs simple ping-pong tests, bouncing messages of increasing size between two processes, whether across a network or within an SMP system. Message sizes are chosen at regular intervals, and with slight perturbations, to provide a complete test of the communication system. Each data point involves many ping-pong tests to provide an accurate timing. It also has an option to measure performance without cache effects. NetPIPE consists of two parts: a protocol independent driver, and a protocol specific communication section. The communication section contains the necessary functions to establish a connection, send and receive data, and close a connection. This part is different for each protocol. However, the interface between the driver and protocol module remains the same. Therefore, the driver does not have to be altered in order to change communication protocols. NetPIPE is a variable time benchmark, which increases the transfer block size from a single byte until transmission time exceeds 1 second. For each block size

8http://www.netperf.org/netperf/NetperfPage.html

CESNET technical report number 18/2003 12 c, three measurements are taken: c - p bytes, c bytes, and c + p bytes, where p is a perturbation factor with a default value of 3. This perturbation allows analysis of block sizes that are possibly slightly smaller or larger than an internal network buffer. NetPIPE uses a ping-pong transfer. This forces the network to transmit just the data block without streaming other data blocks in with the message. The result is the transfer time of a single block, thus providing the information necessary to answer which block size is best, or what is the throughput given a block of size k. NetPIPE produces a file that contains the transfer time, throughput, block size, and transfer time variance for each data point and is easily plotted by any graphing package. Some typical uses:

Measuring the overhead of message-passing protocols.

Help in tuning the optimization parameters of message-passing libraries.

Identify dropouts in networking hardware.

Optimizing driver and OS parameters (socket buffer sizes, etc.).

4.4.2 Automation NetPIPE is a command-line driven program. Command line samples:

node1> NPtcp -r -b 32768 -l 1 -u 1048576

-r = receiver

-b = send and receive TCP buffer sizes

-l = lower bound of block size

-u = upper bound of block size

node2> NPtcp -t -h node1 [options]

-t = transmitter

-h = remote host

CESNET technical report number 18/2003 13 4.4.3 Settings possibilities

specify TCP send/receive buffer sizes

setting lower/upper bound of variable block size

specify increment step size

specify output filename

specify buffers alignment

specify buffer offset

setting stream option (default mode is ”ping-pong”)

4.4.4 Availability See http://www.scl.ameslab.gov/netpipe 9 for more details. Binaries are not available. You can download the latest version NetPIPE 3.5.tar.gz 10. Infiniband module for the Mellanox VAPI has been added, an integrity check option (-I) has been incorporated, and problems with the streaming mode have been fixed.

4.4.5 Required Environment C language compiler

4.4.6 RFC 2544 compatibility

User defined frame format No Support Verifying received frames No Support Bidirectional traffic No Support Setting inter-frame time gap No Support

4.4.7 References Quinn O. Snell, Armin R. Mikler, and John L. Gustafson: NetPIPE: A Network Protocol Independent Performance Evaluator, IASTED Conference Paper

9http://www.scl.ameslab.gov/netpipe 10http://www.scl.ameslab.gov/netpipe/code/NetPIPE 3.5.tar.gz

CESNET technical report number 18/2003 14 4.5 NetSpec 3.0 4.5.1 Description NetSpec is a network level end-to-end performance evaluation tool for Network Experimentation and Measurement. It provides a fairly generic framework that allows a user to control multiple processes across multiple hosts from a central point of control. It uses a scripting language that allows the user to define multiple traffic flows from/to multiple computers. This allows an automatic and reproducible test to be performed. NetSpec exhibits many features like parallel and serial multiple connections, a range of emulated traffic types (FTP, HTTP, MPEG, etc.) on the higher levels, the most widely used transport protocols today, that is TCP and UDP, three different traffic modes, scalability, and the ability to collect system level information from the communicating systems as well as intermediate network nodes. The following figure shows the basic NetSpec architecture.

Figure 3: NetSpec architecture

The controller is a process that supports the user interface, which is currently a file containing a description of an experiment using a simple block structured language in which the connection is the basic unit for an experiment and via the control daemon controls the daemons implementing the test. For every connection in the experiment, the corresponding test daemons are created. These test daemons send or receive data transferred across the connection. Each daemon is responsible for its own report generation after experiment

CESNET technical report number 18/2003 15 execution is complete. The output report is delivered to the controller via the control daemon for viewing by the user. NetSpec supports three basic traffic modes:

Full Stream Mode

Also known as ”full blast mode”, it instructs the test daemons to transmit data as fast as possible.

Burst Mode

The hosts under test transmit data every some specific intervals, specified by the burst period. The burst size and the burst period is passed as a parameter by the user (in blocks/burst and bytes/block). This mode is very useful in real world experiments where rate mismatches might reduce the throughput dramatically.

Queued Burst Mode

The hosts under test transmit data every some specific intervals, specified by the burst period. This mode is a variation of the basic burst algorithm and the burst size and burst period are passed as a parameter by the user. The advantage of this algorithm is that variations in available line rate will not cause it to miss blocks generated by interrupts arriving before previous write completes. The drawback is that characteristics of the traffic are influenced by the queuing delay.

4.5.2 Automation NetSpec consists of several daemon types that are started and controlled by the main netspec daemon (netspecd). NetSpec uses a scripting language that allows the user to define multiple traffic flows from/to multiple computers. This allows an automatic and reproducible test to be performed. A test would be started with:

Netspec script.name

The script given below is of the most widely type used for a TCP point-topoint connection. The first block specifies the characteristics of the traffic source, while the second block specifies the characteristics of the receiver host. Script file sample

1 cluster { 2 test host1 { 3 type = full (blocksize=32768, duration=30);

CESNET technical report number 18/2003 16 4 protocol = tcp (window=32768); 5 own = host1:20200; 6 peer = host2:20200; 7 }

8 test host2 { 9 type = sink (blocksize=32768, duration=30); 10 protocol = tcp (window=32768); 11 own = host2:20200; 12 peer = host1:20200; 13 } 14 }

Figure 4: Test setup with the invoked daemons over TCP

In this particular example, the host with name host1 is the sender system and the host with name host2 is the receiver system. The sender (line 2) sends data in full stream (line 3) mode; it transmits 32768 bytes as fast as possible for 30 seconds (duration of test). For this data transfer TCP (line 4) is used in the transport layer with a window size of 32.7KB. NetSpec can be installed in either of the two ways - inetd installation and stan- dalone installation.

4.5.3 Settings possibilities

specify size of frames and inter-frame time gap in burst modes

setting traffic mode (full stream mode, burst mode or queued burst mode)

specify type of connection (point-to-point, point-to-multipoint or multipoint-to-point connections)

CESNET technical report number 18/2003 17 setting connection mode (serial, parallel or cluster)

specify test duration

specify protocol type

4.5.4 Availability See http://www.ittc.ku.edu/netspec 11 for more details. NetSpec can run on a variety of platforms. The following binaries are available: Digital Unix, Solaris, Linux, SunOs, FreeBSD, Irix. NetSpec manual can be found at http://www.ittc.ukans.edu/netspec/docs/NetSpecUser.pdf 12

4.5.5 Required Environment C language compiler

4.5.6 RFC 2544 compatibility

User defined frame format No Support Verifying received frames No Support Bidirectional traffic It could be made of two single traffics between specified hosts running at the same time in the opposite direction. Setting inter-frame time gap Full Support

4.6 RUDE & CRUDE 0.70 4.6.1 Description RUDE (Real-time UDP Data Emitter) is a small and flexible program that generates traffic to the network, which can be received and logged on the other side of the network with the CRUDE (Collector for RUDE). These programs can generate and measure only UDP traffic. To observe several variables describing the utilization of hardware resources (CPU load, number of interrupts etc.) can be used another free software package - atsar. It can record in regular intervals the

11http://www.ittc.ku.edu/netspec 12http://www.ittc.ukans.edu/netspec/docs/NetSpecUser.pdf

CESNET technical report number 18/2003 18 values of various system counters and parameters together with timestamps, for example the CPU load and number of interrupts generated by the network interface cards. The rude/crude distribution contains several example Perl scripts for basic processing of the decoded crude output and computing jitter. Rude allows definitions of a number of concurrent UDP flows with varying packet size and rate. The TOS field in the IP header can also be set. Reordered and duplicated packets may arrive with arbitrary delays, hence a bitmask with 32 bits describing the fate of the last 32 packets of the flow is kept. Two types of generated flow are implemented - constant and trace. Constant flow means a constant-rate UDP flow, where the packet rate per second and packet size in bytes can be specified. The trace option gives a reference to a text file where the parameters of every single packet has to be given. The smallest time unit for flow definition is 1 ms.

4.6.2 Automation RUDE is driven by a script file, which is used to specify the generated flows. Example of a simple script file follows:

START NOW ## FLOW 1: (flow ID = 25) ## ## Starts immediately at the specified START time with following parameters: ## 400 packets/second with 100 bytes/packet = 40kbytes/sec (1kbyte=1000bytes) (parameters after CONSTANT flow) ## ## Sets the TOS for this flow to LOW_DELAY (0x10) ## ## 9 seconds after that the flow is turned off... ##

0000 25 ON 3001 10.1.1.1:10001 CONSTANT 400 100 TOS 25 0x10 9000 25 OFF

## FLOW 2: (flow ID = 1) ## ## This flow acts as specified in the TRACE configuration file. ##

0000 1 ON 3002 10.1.1.1:10001 TRACE trace_file.txt 9999 1 OFF

Here, the flows 25 and 1 (second field in each row) are specified. The numeric values at the beginning of the rows are time offsets related to a predefined

CESNET technical report number 18/2003 19 global origin when the flow is to be started or its parameters modified. The destination IP address and port are defined as 10.1.1.1 and 10001, respectively, and the source port as 3001, respectively 3002. The source IP address will be determined at run-time as the address of egress interface. The second flow uses for packets definition the external file - trace file.txt. The following command line samples shows, how to run the specified script file. Command line samples:

sender> rude -s sample.cfg

-s