View source for Neil J. Gunther

{{short description|American computer scientist}}

{{Overly detailed|date=August 2020}}
{{Use dmy dates|date=September 2021}}
{{Infobox scientist
| name = Neil James Gunther
| image = NJG BletchleyPk.jpg
| image_size = 203px
| caption = Neil Gunther at [[Bletchley Park]] 2002 <br /> "A quantum leap is neither"
| birth_date = {{Birth date and age|df=yes|1950|8|15}}
| birth_place = [[Preston, Victoria|Preston]], [[Victoria (Australia)|Victoria]], Australia
| field =  Computational information systems (classical and [[quantum]])
| work_institution = [[San Jose State University]]<br /> Syncal Corporation<br /> [[Xerox PARC|Xerox Palo Alto Research Center]]<br /> [[Performance Dynamics Company]] (Founder)<br /> [[École Polytechnique Fédérale de Lausanne]] (EPFL)
| alma_mater = [[La Trobe University]]<br /> [[University of Southampton]]
| doctoral_advisor = Tomas M. Kalotas (Honors)<br />[[Christie Jayaratnam Eliezer|Christie J. Eliezer]] (Masters)<br />[[David Wallace (physicist)|David J. Wallace]] (Doctorate)
| known_for = [[Profiling (computer programming)|Performance analysis]]<br /> [[Capacity planning]] tools<br /> [[Large deviations|Theory of large transients]]<br /> [[Scalability|Universal scalability law]]
}}

'''Neil Gunther''' (born 15 August 1950) is a [[computer]] [[information system]]s [[research]]er best known internationally for developing the [[open-source license|open-source]] [[performance modeling]] software ''[[Pretty Damn Quick]]'' and developing the [http://www.perfdynamics.com/iBook/gcap.html Guerrilla approach] to computer capacity planning and performance analysis. He has also been cited for his contributions to the theory of large [[Transient (computer programming)|transients]] in [[computer systems]] and [[packet network]]s, and his [http://www.perfdynamics.com/Manifesto/USLscalability.html  universal law] of computational [[scalability]].<ref>Microsoft developer blog comparing
[http://blogs.msdn.com/ddperf/archive/2009/04/29/parallel-scalability-isn-t-child-s-play-part-2-amdahl-s-law-vs-gunther-s-law.aspx#9576239 Amdahl's law with Gunther's law] (2009)</ref><ref>Computer Measurement Group [http://cmg.org/measureit/issues/mit58/m_58_8.html Interview part 1] {{Webarchive|url=https://web.archive.org/web/20110722152531/http://cmg.org/measureit/issues/mit58/m_58_8.html |date=22 July 2011 }} [http://www.cmg.org/measureit/issues/mit59/m_59_16.html  and part 2]  (2009)</ref><ref>Springer [https://www.springer.com/computer/communications/book/978-3-540-26138-4?detailsPage=aboutTheAuthor author biography]</ref><ref>Oracle [http://www.hotsos.com/sym_speakers_gunther.html performance experts]</ref><ref>La Trobe University [http://www.latrobe.edu.au/alumni/profiles/full-profile?queries_name_query=Gunther&search_page_22160_submit_button=Submit&current_result_page=0&results_per_page=0&submitted_search_category=&mode=results alumnus profile] {{Webarchive|url=https://web.archive.org/web/20110607095311/http://www.latrobe.edu.au/alumni/profiles/full-profile?queries_name_query=Gunther&search_page_22160_submit_button=Submit&current_result_page=0&results_per_page=0&submitted_search_category=&mode=results |date=7 June 2011 }}</ref><ref>[http://www.neilgunther.com/jcdnjg.pdf Interview] with [[John C. Dvorak]] (1998)</ref>

Gunther is a Senior Member of both the [[Association for Computing Machinery]] (ACM) and the [[Institute of Electrical and Electronics Engineers]] (IEEE), as well as a member of the [[American Mathematical Society]] (AMS), [[American Physical Society]] (APS), [[Computer Measurement Group]] (CMG) and ACM [[SIGMETRICS]].

He is currently focused on developing [[quantum information]] system technologies.<ref name=njp>{{cite web |author1=D. L. Boiko |author2=Neil J. Gunther |author3=N. Brauer |author4=M. Sergio |author5=C. Niclass |author6=G. Beretta. |author7=E. Charbon | title = A Quantum Imager for Intensity Correlated Photons  | publisher = New Journal of Physics | year = 2009 | url = http://www.iop.org/EJ/journal/-page=forthart/1367-2630}}</ref>

== Biography ==
Gunther is an Australian of [[Germans|German]] and Scots ancestry, born in [[Melbourne]] on 15 August 1950. He attended [[Preston East Primary School]] from 1955 to 1956, and [[Balwyn North Primary School]] from 1956 until 1962. For his tenth birthday, Gunther received a copy of the now famous book entitled ''[[The Golden Book of Chemistry Experiments]]'' from an older cousin. Inspired by the book, he started working on various experiments, making use of various chemicals that could be found around in his house. After he spilled some [[potassium permanganate]] solution on his bedroom carpet his mother confined him to an alcove in the garage which he turned into a small [[laboratory]], replete with [[industrial chemical]]s and second-hand [[laboratory glassware]]. Gunther was interested in finding out how things like [[detergents]] and [[oils]] were composed by ''[[Cracking (chemistry)|cracking]]'' them in his [[fractionating column]]. He took particular interest in mixing paints for his art classes, as well as his chemistry classes in [[Balwyn High School]]. His father, being the Superintendent of Melbourne's [[electrical power station]], borrowed an organic chemistry text from the chemists in the quality control laboratory. This ultimately led to an intense interest in synthesizing [[Azo compound|Azo dyes]]. At around age 14, Gunther attempted to predict the color of azo dyes based on the [[chromophore]]-[[auxochrome]] combination. Apart from drawing up empirical tables, this effort was largely unsuccessful due to his lack of knowledge of [[Quantum mechanics|quantum theory]].

=== Post-Doc years ===
Gunther taught physics at [[San Jose State University]] from 1980 to 1981.  He then joined [[Syncal Corporation]], a small company contracted by [[NASA]] and [[JPL]] to develop thermoelectric materials for their deep-space missions. Gunther was asked to analyze the [[thermal stability]] test data from the [[Voyager program|Voyager]] [[Radioisotope thermoelectric generator|RTGs]]. He discovered that the stability of the [[silicon]]-[[germanium]] (Si-Ge) [[thermoelectric alloy]] was controlled by a [[soliton]]-based precipitation mechanism.<ref name=SiGe>{{cite web |author = Gunther, Neil J. | title="Solitons and Their Role in the Degradation of Modified Silicon-Germanium Alloys" in ''Proc. IEEE Fourth Int. Conf. on Thermoelectric Energy Conversion''. | publisher = IEEE, Volume 82CH1763-2, Pages 89–95| year = 1982 |url =http://www.neilgunther.com/DeepSpace/thermo82.pdf}}</ref> JPL used his work to select the next generation of RTG materials for the [[Galileo (spacecraft)|Galileo mission]] launched in 1989.

=== Xerox years ===
In 1982, Gunther joined [[Xerox PARC]] to develop parametric and functional test software for PARC's small-scale [[VLSI]] design fabrication line. Ultimately, he was recruited onto the ''Dragon'' multiprocessor workstation project where he also developed the ''[[PARCbench]]'' multiprocessor benchmark. This was his first foray into computer performance analysis.

1989, he developed a [[Wick rotation|Wick-rotated]] version of [[Richard Feynman]]'s [[Path integral formulation|quantum path integral formalism]] for analyzing performance degradation in large-scale computer systems and packet networks.<ref name=LrgTrans>{{Cite journal | author = Gunther, Neil J. | title = Path Integral Methods for Computer Performance Analysis | journal = Information Processing Letters | volume = 32 | pages = 7–13 | year = 1989 | url = http://dblp.uni-trier.de/rec/bibtex/journals/ipl/Gunther89| doi = 10.1016/0020-0190(89)90061-6 }}</ref>

=== Pyramid years ===
In 1990 Gunther joined [[Pyramid Technology]] (now part of Fujitsu Siemens Computers) where he held positions as senior scientist and manager of the Performance Analysis Group that was responsible for attaining industry-high [[Transaction Processing Performance Council|TPC]] benchmarks on their [[Unix]] multiprocessors. He also performed simulations for the design of the ''Reliant RM1000'' parallel database server.

=== Consulting practice ===
Gunther founded [[Performance Dynamics Company]] as a sole proprietorship, registered in [[California]] in 1994, to provide consulting and educational services for the management of high performance computer systems with an emphasis on [[Profiling (computer programming)|performance analysis]] and enterprise-wide [[capacity planning]]. He went on to release and develop his own [[open-source license|open-source]] [[Profiling (computer programming)|performance modeling]] [[software]] called "PDQ (Pretty Damn Quick)" around 1998. That software also accompanied his first textbook on performance analysis entitled ''The Practical Performance Analyst''. Several other books have followed since then.

== Current research interests ==

=== Quantum information systems ===
In 2004, Gunther has embarked on joint research into quantum information systems based on [[photonics]].<ref name="njp" /> During the course of his research in this area, he has developed a theory of ''[[photon bifurcation]]'' that is currently being tested experimentally at [[École Polytechnique Fédérale de Lausanne]].<ref name=spie>{{cite web | author = Gunther, Neil J. |author2= Charbon, E. |author3= Boiko, D. L. |author4= Beretta, G. | title = Photonic Information Processing Needs Quantum Design Rules | publisher = SPIE Online | year = 2006 | url = http://spie.org/x8567.xml?pf=true&highlight=x2410}}</ref> This represents yet another application of [[path integral formulation]] to circumvent the [[wave-particle duality]] of light.

In its simplest rendition, this theory can be considered as providing the [[quantum]] corrections to the [[Ernst Karl Abbe|Abbe]]-[[John William Strutt, 3rd Baron Rayleigh|Rayleigh]] [[diffraction]] theory of imaging and the [[Fourier optics|Fourier theory]] of [[Fourier transforms|optical information processing]].<ref name=FOptics>{{cite book | author = E. G. Steward| title = Fourier Optics: An Introduction | publisher = Dover | year = 2004 |  isbn = 978-0-486-43504-6}}</ref>

=== Performance visualization ===
Inspired by the work of [[Tukey]], Gunther explored ways to help systems analyst visualize performance in a manner similar to that already available in [[scientific visualization]] and [[information visualization]]. In 1991, he developed a tool called ''Barry'', which employs [[Barycentric coordinates (mathematics)|barycentric coordinates]] to visualize sampled [[CPU usage]] data on large-scale [[multiprocessor]] systems.<ref name=Barry>{{cite book | author = Gunther, Neil J. | title="On the Application of Barycentric Coordinates to the Prompt and Visually Efficient Display of Multiprocessor Performance Data" in Proc. VI International Conf. on Modelling Techniques and Tools for Computer Performance Evaluation, Edinburgh, Scotland | publisher = Antony Rowe Ltd., Wiltshire, U.K., Pages 67–80 | year = 1992 | isbn=978-0-7486-0425-8}}</ref> More recently, he has applied the same 2-[[simplex]] barycentric coordinates to visualizing the [[Apdex]] application performance metric, which is based on [[categorical response time]] data. A barycentric 3-simplex (a [[tetrahedron]]), that can be swivelled on the computer screen using a [[Mouse (computing)|mouse]], has been found useful for visualizing [[packet network]] performance data. In 2008, he co-founded the [http://groups.google.com/group/perfviz?hl=en  PerfViz] [[google group]].

=== Universal Scalability Law ===
The throughput capacity X(N) of a computational platform is given by:

<math display="block">X(N) = \frac{\gamma N}{1 + \alpha (N-1) + \beta N (N-1)} </math>

where N represents either the number of physical processors in the [[computer hardware|hardware]] configuration or the number of users driving the [[software]] application. The parameters <math>\alpha</math>, <math>\beta</math> and <math>\gamma</math> respectively represent the levels of ''contention'' (e.g., queueing for shared resources),  ''coherency'' delay (i.e., latency for data to become consistent) and ''concurrency'' (or effective parallelism) in the system. The <math>\beta</math> parameter also quantifies the retrograde throughput seen in many stress tests but not accounted for in either [[Amdahl's law]] or [[Discrete event simulation|event-based simulations]].
This scalability law was originally developed by Gunther in 1993 while he was employed at [[Pyramid Technology]].<ref name=UniScaling>{{cite web | author = Gunther, Neil J. | title="A Simple Capacity Model for Massively Parallel Transaction Systems" in Proc. CMG Conf., San Diego, California | publisher = CMG, Pages 1035–1044 | year = 1993 | url = http://www.perfdynamics.com/Papers/njgCMG93.pdf}}</ref> Since there are no [[topological]] dependencies, C(N) can model [[Symmetric multiprocessing|symmetric multiprocessors]], [[Multi-core (computing)|multicores]], [[Cluster (computing)|clusters]], and [[grid computing|GRID]] architectures. Also, because each of the three terms has a definite physical meaning, they can be employed as a [[heuristic]] to determine where to make performance improvements in hardware platforms or software applications.

Having a high contention indicates sequential processing that could be parallelized, while having a high coherency suggests excessive dependencies among processes, prompting you to minimize interactions. Also, with help of this equation, you can, in advance, calculate the maximum effective capacity of your system: scaling up your system beyond that point is a waste. <ref>{{Cite book |last=Gunther |first=Neil |title=Guerrilla Capacity Planning: A Tactical Approach to Planning for Highly Scalable Applications and Services |year=2007 |isbn=978-3540261384}}</ref>

At a more fundamental level, the above equation can be derived<ref>{{cite arXiv|author=Neil J. Gunther |title=A General Theory of Computational Scalability Based on Rational Functions |eprint=0808.1431v2|class=cs.PF|year=2008}}</ref> from the [[Machine Repairman]] queueing model:<ref name=Gross>{{cite book |author1=D. Gross  |author2=C. M. Harris  |name-list-style=amp | title = Fundamentals of Queueing Theory | publisher = Wiley-Interscience | year = 1998 | isbn = 978-0-471-17083-9}}</ref>
<blockquote>
'''Theorem (Gunther 2008):''' The universal scalability law is equivalent to the synchronous queueing bound on throughput in a modified Machine Repairman with state-dependent service times.
</blockquote>
The following corollary (Gunther 2008 with <math>\beta = 0</math>) corresponds to Amdahl's law:<ref>{{cite arXiv |title=A New Interpretation of Amdahl's Law and Geometric Scalability |eprint=cs/0210017 |last1=Gunther | first1=Neil J. |year=2002}}</ref>
<blockquote>
'''Theorem (Gunther 2002):''' Amdahl's law for parallel speedup is equivalent to the synchronous queueing bound on throughput in a Machine Repairman model of a multiprocessor.
</blockquote>

== Awards ==
* Senior Member ACM (elected April 2009).
* Senior Member IEEE (elected February 2009).
* Recipient of the [https://web.archive.org/web/20081228120202/http://www.cmg.org/national/michelson-nominations.html A. A. Michelson Award], December 2008.
* Summer Research Institute visitor, [[EPFL]] 2006 and 2007.
* Lecturer, Western Institute of Computer Science, [[Stanford University]], 1997–2000.
* Best paper award, [[Computer Measurement Group|CMG]] conference 1996.
* Visiting Scholar in Materials Science, Stanford University, 1981–1982.
* Science Research Council Studentship, U.K. 1976–1980.
* Commonwealth Postgraduate Scholarship, Australia 1975–1976.

== Selected bibliography ==

=== Theses ===
* ''The Feynman Path Integral in Non-Relativistic Quantum Mechanics and Quantum Electrodynamics,'' La Trobe University (AUS),
BSc Honors dissertation, department of physics, October (1974)
* ''Dynamical Symmetry Groups: The Study and Interpretation of Certain Invariants as Group Generators in Quantum Mechanics, La Trobe University (AUS), MSc dissertation, department of applied mathematics, November (1976)
* ''Broken Dynamical Symmetries in Quantum Field Theory and Phase Transition Phenomena,'' University of Southampton (U.K.), PhD dissertation, department of physics, December (1979)

=== Books ===
* ''The Practical Performance Analyst, '' [[McGraw-Hill]], New York, New York 1998, {{ISBN|0-07-912946-3}} (Out of print)
* ''The Practical Performance Analyst, ''  iUniverse.com Press, Lincoln, Nebraska 2000, {{ISBN|0-595-12674-X}} (Reprint edition)
* ''Performance Engineering: State of the Art and Current Trends,'' Lecture Notes in Computer Science, [[Springer Science+Business Media|Springer-Verlag]]
Heidelberg, Germany, October 2001,  {{ISBN|3-540-42145-9}} ([https://archive.today/20130203032248/http://www.springerlink.com/content/v7glxbdwgf26krlu/?p=8678066742ba45ce8901c431ec7769e6&pi=16 Contributed chapter])
* ''Analyzing Computer System Performance with Perl::PDQ,'' Springer, Heidelberg 2005,  {{ISBN|3-540-20865-8}}
* ''Guerrilla Capacity Planning,'' Springer, Heidelberg 2007, {{ISBN|3-540-26138-9}}

=== Invited presentations ===
* ''Goldstone Modes in First-order Phase Transitions,'' Sixth West Coast Conference on Statistical Mechanics, IBM Research Laboratories, San Jose, June (1980)
* ''Instanton Techniques for Queueing Models of Large Computer Systems: Getting a Piece of the Action,'' SIAM Conference on Applied Probability in Science and Engineering, New Orleans, Louisiana, March (1990)
* ''(Numerical) Investigations into Physical Power-law Models of Internet Traffic Using the Renormalization Group,'' IFORS Conference of Operations Research Societies, Honolulu, Hawaii, 11–15 July (2005)

=== Papers ===
* ''Goldstone Modes in Vacuum Decay and First-order Phase Transitions,'' Journal of Physics, A, 13, 1755–1767 (1980)
* [http://www.hpl.hp.com/techreports/2000/HPL-2000-162.html?jumpid=reg_R1002_USEN ''A Benchmark for Image Retrieval using Distributed Systems over the Internet''] (2000 with G. Beretta)
* [https://arxiv.org/abs/cs/0012022 ''Performance and Scalability Models for a Hypergrowth e-Commerce Web Site''] (2000)
* [https://arxiv.org/abs/cs.NI/0403029 ''Characterization of the Burst Stabilization Protocol for the RR/CICQ Switch''] (2003 with K. J. Christensen and K. Yoshigoe)
* [http://www.actapress.com/PaperInfo.aspx?PaperID=22360 ''Unification of Amdahl's Law, LogP and Other Performance Models for Message-Passing Architectures''] (2005)
* [http://www.hpl.hp.com/techreports/2005/HPL-2005-129.html ''Towards Practical Design Rules for Quantum Communications and Quantum Imaging Devices''] (2005 with G. Beretta)
* ''The Virtualization Spectrum from Hyperthreads to GRIDs,''  Proc. CMG Conf., Reno, Nevada, Dec. (2006)

== References ==
{{reflist|30em}}

== External links ==
* [http://www.perfdynamics.com/ Performance Dynamics Company(SM)]
* {{Blogspot|perfdynamics|Performance Dynamics}}
* [http://genealogy.math.ndsu.nodak.edu/html/id.phtml?id=96149 The Mathematics Genealogy Project]
* {{OEIS el|1=A007814|2=Exponent of highest power of 2 dividing n, a.k.a. the binary carry sequence, the ruler sequence, or the 2-adic valuation of n |formalname=Exponent of highest power of 2 dividing n, a.k.a. the binary carry sequence, the ruler sequence, or the 2-adic valuation of n}}
* [http://catalogue.nla.gov.au/Record/2818802?lookfor=title:(Dynamical%20Symmetry%20Groups)&offset=1&max=2=2 M.Sc. Thesis at National Library of Australia]
* [https://arxiv.org/find/grp_cs,hep-th/1/au:+Gunther_Neil_J/0/1/0/all/0/1 List of papers on arXiv]
* [http://www.perfdynamics.com/Bio/Biblio.html List of papers on computer performance analysis]
* [http://www.neilgunther.com/Dirac/dirac.html Dirac Number 2]
* [http://www.perfdynamics.com/Manifesto/gcaprules.html Guerrilla Manifesto]
* [http://www.perfdynamics.com/Tools/PDQcode.html PDQ performance modeling software]
* [http://groups.google.com/group/perfviz?hl=en Performance Visualization]
* {{LinkedIn URL|https://www.linkedin.com/in/neilgunther}}

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[[Category:1950 births]]
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