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0 pointsfathyb3y ago0 comments

> 1 Processor, 1 Core, 4 Threads

Any idea why StarFive went with this choice for an SBC? I remember POWER7 also having 4 SMT, but it felt right for a superscalar multi-core CPU.

0 comments

rwmj3y ago

The link in the GP comment is wrong - both SoCs have 4 cores, each with a single thread.

The reason why this SoC is faster than HiFive Unmatched seems to be down to architectural improvements.

snvzz3y ago

They both use U74, but different versions.

The one in JH7110 is the 2021Q1 version, AIUI.

Besides faster, it also added B extension.

zu2_3y ago

No. VisionFive2's RISC-V CPU does not have the B extension. I confirmed it on the actual device.

$ cat /proc/cpuinfo processor : 0 hart : 2 isa : rv64imafdc mmu : sv39 uarch : sifive,u74-mc

1 more reply

fathybOP3y ago

Ah, makes much more sense. Thanks!

psychphysic3y ago

Embarrassingly I thought I had a Quad-Core based on `lscpu`.

I have been meaning to make use of it but so far just as a vnc server which works well loading XFCE on the minimal desktop image.

Edit: can see below that it is indeed a quad core... Embarrassed I took an internet strangers off the cuff remark as gospel

snvzz3y ago

It gets more complicated :D

Quad-core 64-bit RISC-V SiFive U74 (RV64GC) processor @ up to 1.5 GHz with 32KB D-Cache, 32KB I-cache

Single-core 64-bit RISC-V SiFive S7 (RV64IMAC) monitor core with 16KB I-cache, 8KB DTIM

Single-core 32-bit RISC-V SiFive E24 (RV32IMFC) real-time control core with 16KB I-cache

photonbeam3y ago

It has 4 cores with 1 thread each, rather than 1 core with 4 thread

j / k navigate · click thread line to collapse

0 comments

rwmj3y ago

The link in the GP comment is wrong - both SoCs have 4 cores, each with a single thread.

The reason why this SoC is faster than HiFive Unmatched seems to be down to architectural improvements.

snvzz3y ago

They both use U74, but different versions.

The one in JH7110 is the 2021Q1 version, AIUI.

Besides faster, it also added B extension.

zu2_3y ago

No. VisionFive2's RISC-V CPU does not have the B extension. I confirmed it on the actual device.

$ cat /proc/cpuinfo processor : 0 hart : 2 isa : rv64imafdc mmu : sv39 uarch : sifive,u74-mc

1 more reply

fathybOP3y ago

Ah, makes much more sense. Thanks!

psychphysic3y ago

Embarrassingly I thought I had a Quad-Core based on `lscpu`.

I have been meaning to make use of it but so far just as a vnc server which works well loading XFCE on the minimal desktop image.

Edit: can see below that it is indeed a quad core... Embarrassed I took an internet strangers off the cuff remark as gospel

snvzz3y ago

It gets more complicated :D

Quad-core 64-bit RISC-V SiFive U74 (RV64GC) processor @ up to 1.5 GHz with 32KB D-Cache, 32KB I-cache

Single-core 64-bit RISC-V SiFive S7 (RV64IMAC) monitor core with 16KB I-cache, 8KB DTIM

Single-core 32-bit RISC-V SiFive E24 (RV32IMFC) real-time control core with 16KB I-cache

photonbeam3y ago

It has 4 cores with 1 thread each, rather than 1 core with 4 thread

j / k navigate · click thread line to collapse