TOP500

Introduction and Objectives

Statistics on high-performance computers are of major interest to manufacturers, users, and potential users. These people wish to know not only the number of systems installed, but also the location of the various supercomputers within the high-performance computing community and the applications for which a computer system is being used. Such statistics can facilitate the establishment of collaborations, the exchange of data and software, and provide a better understanding of the high-performance computer market.

Statistical lists of supercomputers are not new. Every year since 1986 Hans Meuer has published system counts of the major vector computer manufacturers, based principally on those at the Mannheim Supercomputer Seminar. Statistics based merely on the name of the manufacturer are no longer useful, however. New statistics are required that reflect the diversification of supercomputers, the enormous performance difference between low-end and high-end models, the increasing availability of massively parallel processing (MPP) systems, and the strong increase in computing power of the high-end models of workstation suppliers (SMP).

To provide this new statistical foundation, we have decided in 1993 to assemble and maintain a list of the 500 most powerful computer systems. Our list has been compiled twice a year since June 1993 with the help of high-performance computer experts, computational scientists, manufacturers, and the Internet community in general who responded to a questionnaire we sent out; we thank all the contributors for their cooperation. We have also used parts of statistical lists published by others for different purposes.

In the present list (which we call the TOP500), we list computers ranked by their performance on the LINPACK Benchmark. While we make every attempt to verify the results obtained from users and vendors, errors are bound to exist and should be brought to our attention. We intend to continue to update this list half-yearly and, in this way, to keep track with the evolution of computers. Hence, we welcome any comments and information; please use the following mail form. The list is freely available at http://www.top500.org/ where you can create additional sublists and statistics out of the TOP500 database on your own. Here you also have access to slides dealing with the interpretation of the present situation as well as with the evolution over time since we started this project.

The main objective of the TOP500 list is to provide a ranked list of general purpose systems that are in common use for high end applications. The authors of the TOP500 reserve the right to independently verify submitted LINPACK results, and exclude systems from the list which are not valid or not general purpose in nature. By general purpose system we mean that the computer system must be able to be used to solve a range of scientific problems. Any system designed specifically to solve the LINPACK benchmark problem or have as its major purpose the goal of a high TOP500 ranking will be disqualified.

The LINPACK Benchmark

 As a yardstick of performance we are using the `best' performance as measured by the LINPACK Benchmark. LINPACK was chosen because it is widely used and performance numbers are available for almost all relevant systems.

The LINPACK Benchmark was introduced by Jack Dongarra. A detailed description as well as a list of performance results on a wide variety of machines is available in postscript form from netlib. Here you can download the latest version of the LINPACK Report: performance.ps. A parallel implementation of the Linpack benchmark and instructions on how to run it can be found at http://www.netlib.org/benchmark/hpl/.

The benchmark used in the LINPACK Benchmark is to solve a dense system of linear equations. For the TOP500, we used that version of the benchmark that allows the user to scale the size of the problem and to optimize the software in order to achieve the best performance for a given machine. This performance does not reflect the overall performance of a given system, as no single number ever can. It does, however, reflect the performance of a dedicated system for solving a dense system of linear equations. Since the problem is very regular, the performance achieved is quite high, and the performance numbers give a good correction of peak performance.

By measuring the actual performance for different problem sizes n, a user can get not only the maximal achieved performance Rmax for the problem size Nmax but also the problem size N1/2 where half of the performance Rmax is achieved. These numbers together with the theoretical peak performance Rpeak are the numbers given in the TOP500. In an attempt to obtain uniformity across all computers in performance reporting, the algorithm used in solving the system of equations in the benchmark procedure must conform to LU factorization with partial pivoting. In particular, the operation count for the algorithm must be 2/3 n^3 + O(n^2) double precision floating point operations. This excludes the use of a fast matrix multiply algorithm like "Strassen's Method" or algorithms which compute a solution in a precision lower than full precision (64 bit floating point arithmetic) and refine the solution using an iterative approach.

For more information about the Linpack benchmark, please consult with the Linpack FAQ.

TOP500 Description

The TOP500 table shows the 500 most powerful commercially available computer systems known to us. To keep the list as compact as possible, we show only a part of our information here:

• Nworld - Position within the TOP500 ranking

• Manufacturer - Manufacturer or vendor

• Computer - Type indicated by manufacturer or vendor

• Installation Site - Customer

• Location - Location and country

• Year - Year of installation/last major update

• Field of Application

• #Proc. - Number of processors (Cores)

• Rmax - Maximal LINPACK performance achieved

• Rpeak - Theoretical peak performance

• Nmax - Problem size for achieving Rmax

• N1/2 - Problem size for achieving half of Rmax

If Rmax from Table 3 of the LINPACK Report is not available, we use the TPP performance given in Table 1 of the LINPACK Report for solving a system of 1000 equations. In a few cases we interpolated between two measured system sizes or we scaled by cycle times. For models where we did not receive the requested data, the performance of the next smaller system measured is used.

If there should be any changes in the performances given in the following table we will update them.

In addition to cross checking different sources of information, we select randomly a statistical representative sample of the first 500 systems of our database. For these systems we ask the supplier of the information to establish direct contact between the installation site and us to verify the given information. This gives us basic information about the quality of the list in total.

As the TOP500 should provide a basis for statistics on the market of high-performance computers, we limit the number of systems installed at vendor sites. This is done for each vendor separately by limiting the accumulated performance of systems at vendor sites to a maximum of 5% of the total accumulated installed performance of this vendor. Rounding is done in favor of the vendor in question.

In the TOP500 List table, the computers are ordered first by their Rmax value. In the case of equal performances (Rmax value) for different computers, we have chosen to order by Rpeak. For sites that have the same computer, the order is by memory size and then alphabetically.

 TOP500 Authors

The TOP500 list is compiled by Erich Strohmaier of of NERSC/Lawrence Berkeley National Laboratory, Jack Dongarra of the University of Tennessee, Knoxville, Horst Simon of NERSC/Lawrence Berkeley National Laboratory and Martin Meuer of Prometeus (and, from 1993 until his death in 2014, Hans Meuer of the University of Mannheim, Germany).