ISSCC: Eight core MIPS64 processor from Beijing

Godson-3B1500 is a two-node eight-core 172.8Gflop/s MIPS64-compatible processor from Loongson in Beijing – a company whose processors have been adopted in several tablets.

Fabricated in 32nm 10 Cu-layer high-k metal-gate bulk CMOS, it contains 1.14 billion transistors within 182.5mm2 die.

The core, called GS464V, has vector extensions to the MIPS architecture.

The chip operates from 1.0 to 1.3V at frequencies ranging from 1.0 to 1.5GHz, achieving 172.8Gflops at 1.35GHz, with nearly 40W power dissipation.

Compared with the firm’s previous chip, (Godson-3B) a similar GS464V core is used with two primary architectural changes: The last-level cache (LLC) is increased from 4 to 8Mbyte, and a four-way 128kbyte private victim cache is introduced.

“A low-cost asynchronous FIFO between every core and uncore serves to isolate the core in both the frequency and voltage domains. The second architecture change is enhanced high-speed I/O. The point-to-point HyperTransport is updated from 1.0 to 2.0, and the memory access interface improves from DDRII 800 to DDRIII 1200, accompanied by a heterogeneous multi-channel controller architecture,” said the firm, which worked with the Chinese Academy of Sciences in Beijing.

Along with thermal sensors, integrated voltage detector and processor monitor circuits monitor on-chip variation.

“The voltage detector measures the activity of a ring oscillator under test in a configured timing window, and converts the oscillation count to a biased voltage value, which can be observed externally to show short-term or long-term internal IR drops,” said the firm. “The process monitor also contains ring oscillators which consist of unmixed p-mos and n-mos transistors with various thresholds, and is used to check whether the chip remains in the pre-defined process limit during wafer-level test or lifetime debug analysis.”

Paper 3.3: Godson-3B1500: A 32nm 1.35GHz 40W 172.8Gflops 8-Core processor

ISSCC 2013 – 60th Anniversary
Held every year in February in San Francisco, the IEEE’s International Solid State Circuits Conference (ISSCC) is the world showcase for innovative circuit design. This is the 60th conference, and year’s theme is ’60 years of (em)powering the future’.


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