QsNet
Encyclopedia
QsNet is a high speed interconnect designed by Quadrics
used in HPC
clusters, particularly Linux Beowulf Clusters
. Although it can be used with TCP/IP; like SCI
, Myrinet
and Infiniband
it is usually used with a communication API such as MPI
or SHMEM called from a parallel program
.
The interconnect consists of a PCI card in each compute node and one or more dedicated switch chassis. These are connected with a copper cables. Within the switch chassis are a number of line cards that carry Elite switch ASIC
s. These are internally linked to form a fat tree
topology. Like other interconnects such as Myrinet
very large systems can be built by using multiple switch chassis arranged as spine (top-level) and leaf (node-level) switches. Such systems are usually called federated networks.
, there are two generations of QsNet. The older QsNetI was launched in 1998 and used PCI 66-64 cards that had 'elan3' Custom ASIC on them. These gave an MPI bandwidth of around 350 Mbyte
/s unidirectional with 5us latency. QsNet II
was launched in 2003. It used PCI-X
133 MHz cards that carry 'elan4' ASICs. These give an MPI bandwidth of 912 Mbyte/s and MPI latency starting from 1.22us, performance depends on platform used.
In 2004 Quadrics started releasing small to medium switch stand-alone switch configurations called QsNetII E-Series, these configurations range from the 8 to the 128-way systems.
Quadrics
Quadrics was a supercomputer company formed in 1996 as a joint venture between Alenia Spazio and the technical team from Meiko Scientific. They produced hardware and software for clustering commodity computer systems into massively parallel systems. Their highpoint was in June 2003 when six out of...
used in HPC
HPC
HPC may refer to:* Handheld PC* Hasty Pudding cipher* Health Professions Council* Hemangiopericytoma* Hematopoietic progenitor cell* High-performance computing** Windows HPC Server 2008, an operating system for high-performance computing by Microsoft...
clusters, particularly Linux Beowulf Clusters
Beowulf (computing)
A Beowulf cluster is a computer cluster of what are normally identical, commodity-grade computers networked into a small local area network with libraries and programs installed which allow processing to be shared among them...
. Although it can be used with TCP/IP; like SCI
Scalable Coherent Interconnect
SCI, for Scalable Coherent Interface, is a high-speed interconnect standard for shared memory multiprocessing and message passing. The IEEE Std 1596-1992, IEEE Standard for Scalable Coherent Interface was approved by the IEEE standards board on March 19, 1992...
, Myrinet
Myrinet
Myrinet, ANSI/VITA 26-1998, is a high-speed local area networking system designed by Myricom to be used as an interconnect between multiple machines to form computer clusters. Myrinet has much lower protocol overhead than standards such as Ethernet, and therefore provides better throughput, less...
and Infiniband
InfiniBand
InfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable...
it is usually used with a communication API such as MPI
Message Passing Interface
Message Passing Interface is a standardized and portable message-passing system designed by a group of researchers from academia and industry to function on a wide variety of parallel computers...
or SHMEM called from a parallel program
Parallel computing
Parallel computing is a form of computation in which many calculations are carried out simultaneously, operating on the principle that large problems can often be divided into smaller ones, which are then solved concurrently . There are several different forms of parallel computing: bit-level,...
.
The interconnect consists of a PCI card in each compute node and one or more dedicated switch chassis. These are connected with a copper cables. Within the switch chassis are a number of line cards that carry Elite switch ASIC
ASIC
ASIC may refer to:* Application-specific integrated circuit, an integrated circuit developed for a particular use, as opposed to a customised general-purpose device.* ASIC programming language, a dialect of BASIC...
s. These are internally linked to form a fat tree
Fat tree
The fat tree network, invented by Charles E. Leiserson of MIT, is a universal network for provably efficient communication. Unlike an ordinary computer scientist's notion of a tree, which has "skinny" links all over, the links in a fat-tree become "fatter" as one moves up the tree towards the root...
topology. Like other interconnects such as Myrinet
Myrinet
Myrinet, ANSI/VITA 26-1998, is a high-speed local area networking system designed by Myricom to be used as an interconnect between multiple machines to form computer clusters. Myrinet has much lower protocol overhead than standards such as Ethernet, and therefore provides better throughput, less...
very large systems can be built by using multiple switch chassis arranged as spine (top-level) and leaf (node-level) switches. Such systems are usually called federated networks.
, there are two generations of QsNet. The older QsNetI was launched in 1998 and used PCI 66-64 cards that had 'elan3' Custom ASIC on them. These gave an MPI bandwidth of around 350 Mbyte
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
/s unidirectional with 5us latency. QsNet II
QsNet II
QsNet II is the latest generation of Quadrics Interconnect family products.Quadrics QsNetII interfaces to the host computer through the standard IO PCI-X bus.-Architecture:...
was launched in 2003. It used PCI-X
PCI-X
PCI-X, short for PCI-eXtended, is a computer bus and expansion card standard that enhances the 32-bit PCI Local Bus for higher bandwidth demanded by servers. It is a double-wide version of PCI, running at up to four times the clock speed, but is otherwise similar in electrical implementation and...
133 MHz cards that carry 'elan4' ASICs. These give an MPI bandwidth of 912 Mbyte/s and MPI latency starting from 1.22us, performance depends on platform used.
In 2004 Quadrics started releasing small to medium switch stand-alone switch configurations called QsNetII E-Series, these configurations range from the 8 to the 128-way systems.