In computing , remote direct memory access ( RDMA ) is a direct memory access from the memory of one computer into that of another without involving either one's operating system . This permits high-throughput, low- latency networking, which is especially useful in massively parallel computer clusters .
23-489: RDMA may refer to: Remote direct memory access , in computing Radio Disney Music Awards , an annual musical awards ceremony Royal Dutch Medical Association , in the Netherlands Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title RDMA . If an internal link led you here, you may wish to change
46-505: A Fibre Channel vendor. At the 2011 International Supercomputing Conference , links running at about 56 gigabits per second (known as FDR, see below), were announced and demonstrated by connecting booths in the trade show. In 2012, Intel acquired QLogic's InfiniBand technology, leaving only one independent supplier. By 2014, InfiniBand was the most popular internal connection technology for supercomputers, although within two years, 10 Gigabit Ethernet started displacing it. In 2016, it
69-416: A switched fabric topology, as opposed to early shared medium Ethernet . All transmissions begin or end at a channel adapter. Each processor contains a host channel adapter (HCA) and each peripheral has a target channel adapter (TCA). These adapters can also exchange information for security or quality of service (QoS). InfiniBand transmits data in packets of up to 4 KB that are taken together to form
92-485: A choice of BSD license for Windows. It has been adopted by most of the InfiniBand vendors, for Linux , FreeBSD , and Microsoft Windows . IBM refers to a software library called libibverbs , for its AIX operating system, as well as "AIX InfiniBand verbs". The Linux kernel support was integrated in 2005 into the kernel version 2.6.11. Ethernet over InfiniBand, abbreviated to EoIB, is an Ethernet implementation over
115-475: A computer cluster interconnect, IB competes with Ethernet , Fibre Channel , and Intel Omni-Path . The technology is promoted by the InfiniBand Trade Association . InfiniBand originated in 1999 from the merger of two competing designs: Future I/O and Next Generation I/O (NGIO). NGIO was led by Intel , with a specification released in 1998, and joined by Sun Microsystems and Dell . Future I/O
138-559: A direct or switched interconnect between servers and storage systems, as well as an interconnect between storage systems. It is designed to be scalable and uses a switched fabric network topology . Between 2014 and June 2016, it was the most commonly used interconnect in the TOP500 list of supercomputers. Mellanox (acquired by Nvidia ) manufactures InfiniBand host bus adapters and network switches , which are used by large computer system and database vendors in their product lines. As
161-529: A message. A message can be: In addition to a board form factor connection, it can use both active and passive copper (up to 10 meters) and optical fiber cable (up to 10 km). QSFP connectors are used. The InfiniBand Association also specified the CXP connector system for speeds up to 120 Gbit/s over copper, active optical cables, and optical transceivers using parallel multi-mode fiber cables with 24-fiber MPO connectors. Mellanox operating system support
184-430: Is available for Solaris , FreeBSD , Red Hat Enterprise Linux , SUSE Linux Enterprise Server (SLES), Windows , HP-UX , VMware ESX , and AIX . InfiniBand has no specific standard application programming interface (API). The standard only lists a set of verbs such as ibv_open_device or ibv_post_send , which are abstract representations of functions or methods that must exist. The syntax of these functions
207-456: Is duplex. Links can be aggregated: most systems use a 4 link/lane connector (QSFP). HDR often makes use of 2x links (aka HDR100, 100 Gb link using 2 lanes of HDR, while still using a QSFP connector). 8x is called for with NDR switch ports using OSFP (Octal Small Form Factor Pluggable) connectors "Cable and Connector Definitions" . InfiniBand provides remote direct memory access (RDMA) capabilities for low CPU overhead. InfiniBand uses
230-528: Is left to the vendors. Sometimes for reference this is called the verbs API. The de facto standard software is developed by OpenFabrics Alliance and called the Open Fabrics Enterprise Distribution (OFED). It is released under two licenses GPL2 or BSD license for Linux and FreeBSD, and as Mellanox OFED for Windows (product names: WinOF / WinOF-2; attributed as host controller driver for matching specific ConnectX 3 to 5 devices) under
253-605: The Virtual Interface Architecture , RDMA over Converged Ethernet (RoCE), InfiniBand , Omni-Path and iWARP . Applications access control structures using well-defined APIs originally designed for the InfiniBand Protocol (although the APIs can be used for any of the underlying RDMA implementations). Using send and completion queues, applications perform RDMA operations by submitting work queue entries (WQEs) into
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#1732870090773276-494: The network adapter to transfer data from the wire directly to application memory or from application memory directly to the wire, eliminating the need to copy data between application memory and the data buffers in the operating system. Such transfers require no work to be done by CPUs , caches , or context switches , and transfers continue in parallel with other system operations. This reduces latency in message transfer. However, this strategy presents several problems related to
299-520: The burst of the dot-com bubble there was hesitation in the industry to invest in such a far-reaching technology jump. By 2002, Intel announced that instead of shipping IB integrated circuits ("chips"), it would focus on developing PCI Express , and Microsoft discontinued IB development in favor of extending Ethernet. Sun Microsystems and Hitachi continued to support IB. In 2003, the System X supercomputer built at Virginia Tech used InfiniBand in what
322-401: The fact that UD is connection-less, allowing a single host to communicate with any other using a single queue. InfiniBand InfiniBand ( IB ) is a computer networking communications standard used in high-performance computing that features very high throughput and very low latency . It is used for data interconnect both among and within computers. InfiniBand is also used as either
345-453: The fact that the target node is not notified of the completion of the request (single-sided communications). As of 2018 RDMA had achieved broader acceptance as a result of implementation enhancements that enable good performance over ordinary networking infrastructure. For example RDMA over Converged Ethernet (RoCE) now is able to run over either lossy or lossless infrastructure. In addition iWARP enables an Ethernet RDMA implementation at
368-421: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=RDMA&oldid=933080707 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Remote direct memory access RDMA supports zero-copy networking by enabling
391-406: The market, adopted a "buy to kill" strategy. Cisco successfully killed InfiniBand switching companies such as Topspin via acquisition. Of the top 500 supercomputers in 2009, Gigabit Ethernet was the internal interconnect technology in 259 installations, compared with 181 using InfiniBand. In 2010, market leaders Mellanox and Voltaire merged, leaving just one other IB vendor, QLogic , primarily
414-1248: The physical layer using TCP / IP as the transport, combining the performance and latency advantages of RDMA with a low-cost, standards-based solution. The RDMA Consortium and the DAT Collaborative have played key roles in the development of RDMA protocols and APIs for consideration by standards groups such as the Internet Engineering Task Force and the Interconnect Software Consortium. Hardware vendors have started working on higher-capacity RDMA-based network adapters, with rates of 100 Gbit/s reported. Software vendors, such as IBM , Red Hat and Oracle Corporation , support these APIs in their latest products, and as of 2013 engineers have started developing network adapters that implement RDMA over Ethernet. Both Red Hat Enterprise Linux and Red Hat Enterprise MRG have support for RDMA. Microsoft supports RDMA in Windows Server 2012 via SMB Direct . VMware ESXi also supports RDMA as of 2015. Common RDMA implementations include
437-469: The submission queue (SQ) and getting notified of responses from the completion queue (CQ). RDMA can transport data reliably or unreliably over the Reliably Connected (RC) and Unreliable Datagram (UD) transport protocols, respectively. The former has the benefit of preserving requests (no requests are lost), while the latter requires fewer queue pairs when handling multiple connections. This is due to
460-636: Was backed by Compaq , IBM , and Hewlett-Packard . This led to the formation of the InfiniBand Trade Association (IBTA), which included both sets of hardware vendors as well as software vendors such as Microsoft . At the time it was thought some of the more powerful computers were approaching the interconnect bottleneck of the PCI bus, in spite of upgrades like PCI-X . Version 1.0 of the InfiniBand Architecture Specification
483-497: Was estimated to be the third largest computer in the world at the time. The OpenIB Alliance (later renamed OpenFabrics Alliance) was founded in 2004 to develop an open set of software for the Linux kernel. By February, 2005, the support was accepted into the 2.6.11 Linux kernel. In November 2005 storage devices finally were released using InfiniBand from vendors such as Engenio. Cisco, desiring to keep technology superior to Ethernet off
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#1732870090773506-514: Was released in 2000. Initially the IBTA vision for IB was simultaneously a replacement for PCI in I/O, Ethernet in the machine room , cluster interconnect and Fibre Channel . IBTA also envisaged decomposing server hardware on an IB fabric . Mellanox had been founded in 1999 to develop NGIO technology, but by 2001 shipped an InfiniBand product line called InfiniBridge at 10 Gbit/second speeds. Following
529-537: Was reported that Oracle Corporation (an investor in Mellanox) might engineer its own InfiniBand hardware. In 2019 Nvidia acquired Mellanox, the last independent supplier of InfiniBand products. Specifications are published by the InfiniBand trade association. Original names for speeds were single-data rate (SDR), double-data rate (DDR) and quad-data rate (QDR) as given below. Subsequently, other three-letter acronyms were added for even higher data rates. Each link
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