3 ms·

The ugly truth though is that "catalog parts" carry with it a whole boatload of overhead in the form of sockets/memory infrastructure/voltage regulators/cooling

The ugly truth though is that "catalog parts" carry with it a whole boatload of overhead in the form of sockets/memory infrastructure/voltage regulators/cooling standards etc. The current "big money" is in being the core that gets integrated into a phone or tablet. It makes me sad too as this is a pretty spiffy micro-architecture to play around with.

OhMeadhbh 3y ago
Oh hey Chuck! Yes. That's where the big money is. It seems their current top-of-the-line core is on par with an A72 or A77. I'm not sure how it stacks up against an Apple M1. My take on SiFive is it's at the point that it COULD compete, but they have to get more mind-share. If you're Samsung or Apple (or MediaTek or Allwinner or Rockchip or ...), you probably have experience with the ARM ecosystem and tools. Presumably you have a history with a business model and have factored in whatever royalties you're paying ARM into your cost of operations. It's a risk to set that aside and start using a different architecture, so you would want to have some quantifiable benefit before you ditched ARM for RISC-V. It seems to me that clearly elucidating that benefit to potential customers is an important part of this equation. SiFive's earlier designs seemed to have smaller PPA numbers, so that's nice. But they were for in-order execution w/o macro fusion or speculative branching, so they were a little closer to A53s in performance per watt. If you had a RV64 design with the performance per watt of an A77, but with a power/area budget 20% lower, that might have a REAL impact on yield and cost. That would be a thing to crow about. But that's not the type of crowing I see happening on the SiFive web page. I keep thinking a catalog part with maybe a pair of U-54s, a pair of 270s and a pair of 670s plus typical SoC peripherals would be a great way to introduce developers to what SiFive designs could do. They could give dev boards to Samsung, Zero, Google, LTE engineers who could tweak the existing android RISC-V android images to get an idea for performance and power use. Maybe they could sell Apple on the idea of acquihiring SiFive. Apple's never been skiddish about changing processor architectures or suppliers. So... to recap... I'm thinking catalog parts mostly as a vehicle to prove to potential customers your IP can be fabbed to meet their power / performance / yield / cost targets. And if I can buy a couple hundred of these boards for a different project, then I'm even happier.
- brucehoult 3y ago
  > It seems their current top-of-the-line core is on par with an A72 or A77 Their current core, the P870 (the subject of the post we are commenting on) is on par with Cortex X2, announced just over 2 years ago in May 2021. A76 class was the P550, announced in June 2021, 3 years after the A76's May 2018 announcement. A72 class was their U84, back in October 2019, 4 1/2 years after the A72's February 2015 announcement. The time gap has been coming steadily down. All of these cores, both Arm and SiFive, take about four years to get into cheap mass produced catalog part chips and boards e.g. the A76 RK3588 just started appearing in SBCs around May 2022. A72 to Pi 4 was 4 1/2 years. I don't know how much you can pick up a JH7110 with four 1.5 GHz U74s (plus that S7) for, but Milk-V are selling a compute module board with one for $34 https://arace.tech/products/milk-v-mars-cm?variant=42342172262580 https://arace.tech/products/milk-v-mars-cm?variant=423421722...
- ChuckMcM 3y ago
  > So... to recap... I'm thinking catalog parts mostly as a vehicle to prove to potential customers your IP can be fabbed to meet their power / performance / yield / cost targets. And if I can buy a couple hundred of these boards for a different project, then I'm even happier. Oh I don't disagree, lowering the cost to field a system out of your micro-architecture increases the likely hood a design engineer will design it into their own design. This effect singlehandedly sustained the x86 product line until it didn't.

OhMeadhbh 3y ago

Oh hey Chuck! Yes. That's where the big money is. It seems their current top-of-the-line core is on par with an A72 or A77. I'm not sure how it stacks up against an Apple M1. My take on SiFive is it's at the point that it COULD compete, but they have to get more mind-share. If you're Samsung or Apple (or MediaTek or Allwinner or Rockchip or ...), you probably have experience with the ARM ecosystem and tools. Presumably you have a history with a business model and have factored in whatever royalties you're paying ARM into your cost of operations. It's a risk to set that aside and start using a different architecture, so you would want to have some quantifiable benefit before you ditched ARM for RISC-V. It seems to me that clearly elucidating that benefit to potential customers is an important part of this equation. SiFive's earlier designs seemed to have smaller PPA numbers, so that's nice. But they were for in-order execution w/o macro fusion or speculative branching, so they were a little closer to A53s in performance per watt. If you had a RV64 design with the performance per watt of an A77, but with a power/area budget 20% lower, that might have a REAL impact on yield and cost. That would be a thing to crow about. But that's not the type of crowing I see happening on the SiFive web page. I keep thinking a catalog part with maybe a pair of U-54s, a pair of 270s and a pair of 670s plus typical SoC peripherals would be a great way to introduce developers to what SiFive designs could do. They could give dev boards to Samsung, Zero, Google, LTE engineers who could tweak the existing android RISC-V android images to get an idea for performance and power use. Maybe they could sell Apple on the idea of acquihiring SiFive. Apple's never been skiddish about changing processor architectures or suppliers. So... to recap... I'm thinking catalog parts mostly as a vehicle to prove to potential customers your IP can be fabbed to meet their power / performance / yield / cost targets. And if I can buy a couple hundred of these boards for a different project, then I'm even happier.

brucehoult 3y ago
> It seems their current top-of-the-line core is on par with an A72 or A77 Their current core, the P870 (the subject of the post we are commenting on) is on par with Cortex X2, announced just over 2 years ago in May 2021. A76 class was the P550, announced in June 2021, 3 years after the A76's May 2018 announcement. A72 class was their U84, back in October 2019, 4 1/2 years after the A72's February 2015 announcement. The time gap has been coming steadily down. All of these cores, both Arm and SiFive, take about four years to get into cheap mass produced catalog part chips and boards e.g. the A76 RK3588 just started appearing in SBCs around May 2022. A72 to Pi 4 was 4 1/2 years. I don't know how much you can pick up a JH7110 with four 1.5 GHz U74s (plus that S7) for, but Milk-V are selling a compute module board with one for $34 https://arace.tech/products/milk-v-mars-cm?variant=42342172262580 https://arace.tech/products/milk-v-mars-cm?variant=423421722...
ChuckMcM 3y ago
> So... to recap... I'm thinking catalog parts mostly as a vehicle to prove to potential customers your IP can be fabbed to meet their power / performance / yield / cost targets. And if I can buy a couple hundred of these boards for a different project, then I'm even happier. Oh I don't disagree, lowering the cost to field a system out of your micro-architecture increases the likely hood a design engineer will design it into their own design. This effect singlehandedly sustained the x86 product line until it didn't.