✧✦Catherine✦✧Mar 28

so i took apart an NVIDIA BF-3 card and would anybody who understands it please enlighten me why it has on board:

  • Puya P24CM02 (256 KB)
  • Winbond W25Q256JVBM (32 MB)
  • Winbond W25Q512JVBQ (64 MB)
  • MXIC MX66L2G45G (256 MB)
  • a Kingston EMMC128-TY29 (128 GB)
  • a Microchip CEC1736 root-of-trust controller (which embeds 2 or 4 MB of internal SPI flash and is connected to the other three SPI flashes... I think)
  • and an ASPEED chip with a p/n I did not extract from under thermal compound looking suspiciously similar to those awful BMC devices, connected to 1 GB of Samsung DDR4

I wasn't prepared for a 1 Tbit eMMC connected directly to the main ASIC. what could it possibly be storing there? the field engineer's porn stash?

Show thread✧✦Catherine✦✧Mar 28
this is literally more flash than in most laptops, even if you include Thunderbolt controllers and the display firmware
Show thread✧✦Catherine✦✧Mar 28
apparently the network card runs ubuntu
Show threadmccMar 28
@whitequark what would be necessary to "reverse the flow" so that this is the "computer" and the card can run with no other peripherals except power
Show thread✧✦Catherine✦✧Mar 28
@mcc I literally just assembled this on my desk and it doesn't do this out of the box but I am led to believe that you can get an SKU which has a PCIe Root Complex and can talk to NVMe all on its own
Show threadmccMar 28
@whitequark fantastic. Or terrible. Whichever
Show thread✧✦Catherine✦✧Mar 28
@mcc it is pretty cool I think to be able to do that
Show threadmcc
@whitequark so related to https://social.hackerspace.pl/@implr/116308523937232041 I guess the thing that would make me consider it "terrible" is the question of, if they can make this, it implies they could have just as easily made an embedded board I would find much more interesting
Mar 28 at 9:27pmWeb
Show threadJohn RipleyMar 28
@mcc It’s such a horribly inefficient chip, it unfortunately wouldn’t make an interesting standalone board. It’s only compelling to use if you need the firehose of that much PCIe and network bandwidth, and even then it only makes sense in a niche of legacy x86 servers. All its functions can be achieved on the host with less power used, which if you have a rack power budget to stay within, means it’s actually overall a _decelerator_.
Show threadimplrMar 29
@jripley
Yes, a BF2/3 is basically a rpi4 or 5 glued to a cx4 NIC, with power use higher than both of those.
However, I don't think it's fair to compare an old bluefield with a modern x86 host. The newer incarnations have Neoverse V2 cores which should be just as (if not more) efficient than current x86.
There's a reason most hyperscalers use a variant of this tech for their clouds, and they're extremely sensitive to power OPEX.
Show threadJohn RipleyMar 29

@implr My biggest takeaway from spending a while redesigning data center hardware from the ground up, is that everyone says they care about OPEX, but when you look under the hood, it’s full of gross inefficiencies because it is fully Conway’s Law inside. Nobody is willing to do work which crosses organizations.

That’s where things like BF come in: they’re supposedly hardware (Linux in a trench coat) and a driver, so you can outsource all the new features to a vendor, and everyone’s happy.