Neha Patil (Editor)

Loongson

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Common manufacturer(s)
  
STMicroelectronics

Min. feature size
  
180 nm to 28 nm

Max. CPU clock rate
  
200 MHz to 1.5 GHz

Instruction set
  
MIPS64

Loongson

Marketed by
  
Loongson Technology, Jiangsu Lemote Tech Co., Ltd, Dawning Information Industry, and others

Designed by
  
Institute of Computing Technology (ICT), Chinese Academy of Sciences, Jiangsu Lemote Tech Co., Ltd

Loongson (simplified Chinese: 龙芯; traditional Chinese: 龍芯; pinyin: Lóngxīn; literally: "Dragon Core") is a family of general-purpose MIPS64 CPUs developed at the Institute of Computing Technology (ICT), Chinese Academy of Sciences (CAS) in China. The chief architect is Professor Hu Weiwu. It was formerly called Godson.

Contents

Loongson is the result of a public–private partnership. BLX IC Design Corporation was founded in 2002 by ICT and Jiangsu Zhongyi Group. Based in Beijing, BLX focuses on designing the 64-bit Loongson general-purpose and embedded processors, together with developing software tools and reference platforms.

STMicroelectronics fabricates and markets Loongson chips for BLX, which is fabless.

MIPS patent issues

The current Loongson instruction set is a MIPS64, but the internal microarchitecture is independently developed by ICT. Early implementations of the family lacked four instructions patented by MIPS Technologies to avoid legal issues.

In 2007, a deal was reached by MIPS Technologies and ICT. STMicroelectronics bought a MIPS license for Loongson, and thus the processor can be promoted as MIPS-based or MIPS-compatible instead of MIPS-like.

In June 2009, ICT licensed the MIPS32 and MIPS64 architectures directly from MIPS Technologies.

In August 2011, Loongson Technology Corp. Ltd. licensed the MIPS32 and MIPS64 architectures from MIPS Technologies, Inc. for continued development of MIPS-based Loongson CPU cores.

Loongson 1

The first revision of the Loongson architecture, the Loongson1 (Godson-232 core) is a pure 32-bit CPU running at a clock speed of 266 MHz. It is fabricated with 0.18 micron CMOS process, has 8 KB of data cache, 8 KB of instruction cache and a 64-bit floating-point unit, capable of 200 double-precision MFLOPS. It is intended for embedded applications, such as point of sale (POS) systems, where a high performance 64-bit architecture is not needed.

Loongson 2

The Loongson 2 adds 64-bit ability to the Loongson architecture. Initially running at 500 MHz, later revisions to Godson 2E were produced that run up to 1 GHz. The Godson 2F, released to market in early 2008, ran at 1.2 GHz.

Loongson 2E

  • four-way superscalar, out-of-order execution, 64-bit MIPS architecture processor core
  • Little-endian MIPS III-compatible ISA
  • five execution units: two ALUs, two FPUs, and one address generation unit (AGU)
  • SIMD unit is integrated with one of the two FPUs
  • Separate 64/64 KB instruction and data L1 caches
  • On-chip 512 KB four-way set-associative L2 cache
  • Integrated DDR memory controller
  • Max. 7 W at 1 GHz
  • Loongson 2F

  • four-way superscalar, out-of-order execution, 64-bit MIPS architecture processor core
  • Little-endian MIPS III-compatible ISA
  • five execution units: two ALUs, two FPUs, and one address generation unit (AGU)
  • SIMD unit is integrated with one of the two FPUs
  • Separate 64/64 KB instruction and data L1 caches
  • On-chip 512 KB four-way set-associative L2 cache
  • Integrated DDR2 memory controller
  • Integrated very simple video accelerator
  • Software-controlled dynamic power management
  • Max. 4 W at 1 GHz
  • Godson-2G

  • 1.0 GHz, 65 nm CMOS, 3 W
  • 100 M transistors, area 60 mm^2
  • Single GS464 core
  • 64-bit MIPS64 compatible
  • HW support X86 binary translation
  • Four-issue, OOO
  • 64 KB+64 KB L1 (four-way)
  • 1 MB L2 cache
  • On-chip DDR2/3 controller
  • 16-bit HT
  • PCI/PCIX, LPC, GPIO, etc.
  • Godson-2H

  • 1 GHz, 65 nm
  • Single GS464V core (HD media decoding)
  • 512 KB L2 cache
  • 3D low-power GPU
  • DDR2/3 memory controller
  • PCIE 2.0 controller
  • SATA, USB, GMAC controller
  • LPC, SPI, UART, etc.
  • Loongson 3

    The 65 nm Loongson 3 (Godson-3) is able to run at a clock speed near 1 GHz, with 4 CPU cores (~15 W) first and 8 cores later (40 W). In April 2010, Loongson 3A was released with DDR2/3 DRAM support.

    Loongson 3B

    There are two versions of the Loongson-3B (Godson-3B), the first featuring a 32 nm 6-core processor, and the second version having a 28 nm 8-core processor. Each version can be clocked from 1.2 GHz to 1.5 GHz. Loongson-3B has exceptional energy efficiency in terms of performance per watt - executing 192 GFLOPS using 40 watts. Each CPU core has 64 KB L1 cache and 128 KB L2 cache. All the cores share a common 8 MB L3 cache, which helps to reduce the cache miss rate.

    Recently, ICT has launched a Loongson-3B-based six-core desktop solution. Technical specifications:

  • Mini-ITX motherboard with Loongson-3B CPU
  • ATI RS780E (AMD 780E) southbridge with 128 MB integrated graphics
  • ATI SBx00 Azalia on-board audio
  • up to 16 GB DDR3 memory
  • Intel 82574L gigabit network interface
  • PCI, PCIe, 4 SATA ports, USB and other peripheral interfaces
  • Can optionally be equipped with AMD HD6770 discrete graphics, and HDD or SSD hard drive
  • This desktop solution uses an optimized version of Fedora 13, with a lot of software ported and available, such as Kingsoft (WPS) office suite. The manufacturer states that the user experience of the desktop solution has been significantly improved over its Loongson-3A based predecessor. Results of a benchmark test, conducted in April 2014, are available

    Hardware-assisted x86 emulation

    The Loongson 3 adds over 200 new instructions over Loongson 2. Their addition has the specific benefit of speeding up Intel x86 CPU emulation at a cost of 5% of the total die area. The new instructions help with emulation performance, for example QEMU (the only known example). The new instructions reduce the impact of executing x86/CISC-style instructions in the MIPS pipeline. With added improvements in QEMU from ICT, Loongson-3 achieves an average of 70% the performance of executing native binaries when running x86 binaries from nine benchmarks.

    Supported software

    Unlike processors from Intel, Advanced Micro Devices or VIA Technologies, Loongson does not directly support the x86 instruction set. The processor's main operating system is Linux, while in theory any OS with MIPS support should also work. For example, Windows CE was ported to a Loongson-based system with minimal effort. In 2010, Lemote ported an Android distribution to the Loongson platform.

    Many operating systems work on Loongson:

    Linux

  • Android
  • Arch Linux (In development)
  • CLFS MIPS 32/64-bit, Multilib
  • Debian 6.0, 7.0 (Wheezy), and 8.0, specifically their mipsel port
  • Fedora n32, work in progress
  • Gentoo Linux n32, specifically their mipsel port
  • gNewSense
  • Loonux
  • Mandriva Linux was default system shipped with Gdium
  • NixOS n32
  • Parabola GNU/Linux-libre, specifically their mips64el port
  • Red Flag Linux
  • UTUTO, work in progress
  • XianGe Linux n32
  • BSD

  • FreeBSD, kfreebsd-yeeloong
  • NetBSD, evbmips
  • OpenBSD, OpenBSD/loongson
  • Compiler support

    The GNU Compiler Collection (GCC) is the main compiler for software development on the Loongson platform.

    ICT also ported Open64 to the Loongson II platform.

    User applications

    Open source applications on Linux Platform can be ported with little effort. Most common open source applications (including OpenOffice.org, Mozilla Firefox, Pidgin, and MPlayer) and applications written for the Java platform are supported. For .NET applications, an unofficial port of the Mono Common Language Runtime is available online.

    Loongson-based systems

    In March 2006, a €100 Loongson II computer design called Longmeng (Dragon Dream) was announced by Lemote.

    In June 2006 at Computex'2006, YellowSheepRiver announced the Municator YSR-639, a small form factor computer based on the 400 MHz Loongson 2.

    Currently, Loongson boxes that come with a 667 MHz Godson 2E processor or an 800 MHz Godson 2F processor are sold in China at CNY 1599 (US$200) or CNY 1800 respectively without monitor, mouse, or keyboard.

    As of July 2008, two manufacturers have announced Loongson 2F products for sale outside China.

  • Van der Led, a Dutch company, announced an 8.9 in subnotebook, named Jisus, in April 2008. As of September 2008, however, no orders have been fulfilled, the manufacturer does not respond to inquiries, and the product is no longer on their catalogue.
  • EMTEC, a French company, announced in June 2008 a 10″ subnotebook under the brand name Gdium[2], to be sold for "less than 399€" running Mandriva Linux. EMTEC announced the subnotebook would be available for sale in September in Europe, the United States, and China. EMTEC has already shown the devices in public events, and is reaching out to the developer community through the "one laptop per hacker" program.
  • As of November 2008 the new 8.9" netbook from the Chinese manufacturer Lemote that replaced mengloong, Yeeloong (Portable Dragon), running Debian, is available in Europe from the Dutch company Tekmote Electronics.

    Loongson 3A laptop

    Loongson insiders revealed a new model based on the Loongson 3A quad-core laptop has been developed and is expected to launch in August 2011. With a similar design to the MacBook Pro from Apple Inc., it will carry a Linux operating system by default.

    In September 2011, Lemote announced the Yeeloong-8133 13.3" laptop featuring 900 MHz, quad-core Loongson-3A/2GQ CPU.

    Supercomputers

    On 26 December 2007, China revealed its first Loongson based supercomputer with performance 1 teraFLOPS of peak performance, and about 350 GFLOPS measured by LINPACK in Hefei, designated as KD-50-I. This supercomputer was designed by a joint team led by Chen Guoliang at the computer science technology department of the University of Science and Technology of China and ICT (the secondary contractor). KD-50-I is the first Chinese built supercomputer to utilize domestic Chinese CPUs, with a total of more than 336 Loongson-2F CPUs, and nodes are interconnected by Ethernet. The size of the computer was roughly equivalent to a household refrigerator and the cost was less than RMB 800,000 (approximately USD 120,000, EUR 80,000).

    On 20 April 2010, USTC announced successful development of Loongson 3A based KD-60-1. The new supercomputer is a cluster of standard blade servers with a total of over 80 quad-core Loongson processors, providing theoretical peak performance of 1 TFLOPS and reduces power consumption by 56% compared to the KD-50-I system that has similar performance.

    On 26 December 2012, USTC announced successful development of Loongson 3B based KD-90-1. The new supercomputer is a cluster of standard blade servers with a total of over 10 octo-core Loongson processors, providing theoretical peak performance of 1 TFLOPS, and reduces power consumption by 62% compared to the KD-60 system that has similar performance.

    Dawning 6000

    The high-performance Dawning 6000, which has a projected speed of over one quadrillion operations per second, will incorporate the Loongson processor as its core. Dawning 6000 is currently jointly developed by the Institute of Computing Technology under the Chinese Academy of Sciences and the Dawning Information Industry Company. Li Guojie, chairman of Dawning Information Industry Company and director and academician of the Institute of Computing Technology, said research and development of the Dawning 6000 is expected to be completed in two years. By then, Chinese-made high-performance computers will be expected to achieve two major breakthroughs: first, the adoption of domestic-made central processing units (CPUs); second, the existing cluster-based system structure of high-performance computers will be changed once the computing speed reaches one quadrillion operations per second.

    TopStar ATX

    Topstar has also released a pair of Mini-ATX based motherboards, the TEB-6040M and TEB-5040.

    Major events

    Development of the first Loongson chip was started in 2001.

    On 25 June 2008, Hu Weiwu (chief designer of Loongson processors) gave a keynote speech at ISCA 2008, held in Beijing. The topic of the speech was "Research and Development of Godson processors".

    2010 January, Jiangsu province plans to buy 1.5 million Loongson PCs.

    References

    Loongson Wikipedia