Editing Myrinet

{{Short description|Local area networking system}}
{{more citations needed|date=September 2014}}
'''Myrinet''', ANSI/VITA 26-1998, is a high-speed [[local area network]]ing system designed by the company Myricom to be used as an interconnect between multiple machines to form [[computer cluster]]s.

==Description==
Myrinet was promoted as having lower protocol overhead than standards such as [[Ethernet]], and therefore better [[throughput]], less interference, and lower [[Latency (engineering)|latency]] while using the host CPU. Although it can be used as a traditional networking system, Myrinet is often used directly by programs that "know" about it, thereby bypassing a call into the [[operating system]].

Earlier versions of Myrinet used a variety of media and connectors:<ref>Guide to Myrinet/PCI Host Interfaces,  Myricom, Inc., 18 February 2002</ref>
* Generation 2 used copper media with [[D-subminiature|DC-37]] (Myrinet-LAN, M2L-* controllers and switches) or microribbon (Myrinet-SAN, M2M-*) connectors.
* Generation 3 used copper media with HSSDC (Myrinet-Serial, M3S-*) or microribbon (Myrinet-SAN, M3M-*) connectors, or fiber with LC-connectors (Myrinet-Fiber, M3F-*).

The later versions of Myrinet physically consist of two [[fibre optic]] cables, upstream and downstream, connected to the host computers with a single connector. Machines are connected via low-overhead [[router (computing)|router]]s and [[Network switch|switch]]es, as opposed to connecting one machine directly to another. Myrinet includes a number of fault-tolerance features, mostly backed by the switches. These include flow control, error control, and "heartbeat" monitoring on every link. The "fourth-generation" Myrinet, called Myri-10G, supported a 10&nbsp;Gbit/s data rate and can use [[10 Gigabit Ethernet]] on [[PHY]], the physical layer (cables, connectors, distances, signaling). Myri-10G started shipping at the end of 2005.

Myrinet was approved in 1998 by the [[American National Standards Institute]] for use on the [[VMEbus]] as ANSI/VITA 26-1998.<ref>{{Cite book |title= American National Standard for Myrinet-on-VME Protocol Specification |url= https://ph-dep-ese.web.cern.ch/ph-dep-ese/crates/standards/Av26.pdf |date= November 2, 1998 |publisher= VMEbus International Trade Association |isbn= 1-885731-15-9 |access-date= September 1, 2016 |archive-date= November 11, 2014 |archive-url= https://web.archive.org/web/20141111221726/https://ph-dep-ese.web.cern.ch/ph-dep-ese/crates/standards/Av26.pdf |url-status= live }}</ref> One of the earliest publications on Myrinet is a 1995 IEEE article.<ref>{{Cite journal |doi = 10.1109/40.342015|title = Myrinet: A gigabit-per-second local area network|year = 1995|last1 = Boden|first1 = N.J.|last2 = Cohen|first2 = D.|last3 = Felderman|first3 = R.E.|last4 = Kulawik|first4 = A.E.|last5 = Seitz|first5 = C.L.|last6 = Seizovic|first6 = J.N.|last7 = Wen-King Su|journal = IEEE Micro|volume = 15|pages = 29–36}}</ref>

=== Performance ===
{| class="wikitable"
|+
! colspan="2" |Generation
!Year<ref>{{Cite book |title=Encyclopedia of Parallel Computing |publisher=IEEE |year=2011 |isbn=978-0-387-09765-7 |editor-last=Padua |editor-first=David |pages=1239–1247 |doi=10.1007/978-0-387-09766-4}}</ref>
!Bandwidth
!Notes
|-
|1
|Myrinet
|1994
|0.64 Gbit/s
|[[Positive emitter-coupled logic|PECL]] PHY
|-
| rowspan="2" |2
|Myrinet-LAN
| rowspan="2" |1996
| rowspan="2" |1.28 Gbit/s
|Backwards compatible with original Myrinet.<br/>[[LVDS]] PHY for 1.28&nbsp;Gbit/s operation.<ref>{{Cite web |date=1997-01-17 |title=M2M-M2F description |url=http://www.myri.com/myrinet/linkdev/m2m-m2f.html |access-date=2023-11-11 |archive-url=https://web.archive.org/web/19970117054039/http://www.myri.com/myrinet/linkdev/m2m-m2f.html |archive-date=1997-01-17 }}</ref>
|-
|Myrinet-SAN
|System-Area Network, shorter reach (3m) but lower cost<ref>{{Cite web |date=1997-01-17 |title=Myrinet - A Brief, Technical Overview |url=http://www.myri.com/myrinet/overview.html |access-date=2023-11-11 |archive-url=https://web.archive.org/web/19970117053706/http://www.myri.com/myrinet/overview.html |archive-date=1997-01-17 }}</ref>
|-
|3
|Myrinet-2000
|2000
|2 Gbit/s
|Backwards-compatible with [[Gigabit Ethernet]]
|-
|4
|Myri-10G
|2005
|10 Gbit/s
|Backwards-compatible with [[10 Gigabit Ethernet]]
|}
Myrinet is a lightweight protocol with little overhead that allows it to operate with throughput close to the basic signaling speed of the physical layer. For supercomputing, the low latency of Myrinet is even more important than its throughput performance, since, according to [[Amdahl's law]], a high-performance parallel system tends to be bottlenecked by its slowest sequential process, which in all but the most [[embarrassingly parallel]] supercomputer workloads is often the latency of message transmission across the network.

=== Deployment ===
According to Myricom, 141 (28.2%) of the June 2005 [[TOP500]] supercomputers used Myrinet technology. In the November 2005 TOP500, the number of supercomputers using Myrinet was down to 101 computers, or 20.2%, in November 2006, 79 (15.8%), and by November 2007, 18 (3.6%), a long way behind [[gigabit Ethernet]] at 54% and [[InfiniBand]] at 24.2%.

In the June 2014 TOP500 list, the number of supercomputers using Myrinet interconnect was 1 (0.2%).<ref>{{Cite web |url=http://www.top500.org/statistics/list/ |title=List Statistics |access-date=2014-01-13 |archive-date=2018-07-18 |archive-url=https://web.archive.org/web/20180718013118/https://www.top500.org/statistics/list/ |url-status=live }}</ref><ref>{{Cite web |url=http://www.top500.org/statistics/details/connfam/2 |title=Deployment Time Series Chart |access-date=2014-01-16 |archive-date=2014-02-01 |archive-url=https://web.archive.org/web/20140201110442/http://www.top500.org/statistics/details/connfam/2 |url-status=live }}</ref>

In November, 2013, the assets of Myricom (including the Myrinet technology) were acquired by CSP Inc.<ref>{{Cite web |title= CSP, Inc. Broadens MultiComputer Business Opportunities With Asset Purchase of Myricom, Inc. |work= Press Release |date= November 6, 2013 |url= http://globenewswire.com/news-release/2013/11/06/587343/10056536/en/CSP-Inc-Broadens-MultiComputer-Business-Opportunities-With-Asset-Purchase-of-Myricom-Inc.html |access-date= September 1, 2016 |archive-date= September 11, 2016 |archive-url= https://web.archive.org/web/20160911083804/http://globenewswire.com/news-release/2013/11/06/587343/10056536/en/CSP-Inc-Broadens-MultiComputer-Business-Opportunities-With-Asset-Purchase-of-Myricom-Inc.html |url-status= live }}</ref> In 2016, it was reported that [[Google]] had also offered to buy the company.<ref>{{Cite web |title= Google crafts custom networking CPU with parallel computing links |work= The Register |url= https://www.theregister.co.uk/2016/02/09/google_processor/ |author= Chris Williams |date= February 9, 2016 |access-date= September 1, 2016 |archive-date= August 11, 2016 |archive-url= https://web.archive.org/web/20160811165403/http://www.theregister.co.uk/2016/02/09/google_processor/ |url-status= live }}</ref>

==See also==
*[[HIPPI]]
*[[InfiniBand]]
*[[List of device bandwidths]] 
*[[NUMAlink]]
*[[Quadrics (company)]]
*[[RapidIO]]
*[[Scalable Coherent Interconnect]] (SCI)

==References==
{{Reflist}}

==External links==
* {{webarchive |url=https://web.archive.org/web/20130816035225/http://www.myricom.com/ |date=August 16, 2013 |title=Myrinet site}}
* [http://www.cspi.com CSPI], current owner or Myrinet.

[[Category:Supercomputing]]
[[Category:Computer networks]]