If a Pi is capable of this already, why not replace the Ethernet, charging, micro-HDMI, and USB ports with a boatload of type-C Thunderbolt ports (plus support for the HDMI 1.4 alt mode)? Would 8xUSB-C cost that much more than 1xUSB-C+1xEthernet+2xMicro-HDMI+2xUSB3+2xUSB2 (with no PCI Express), in exchange for a considerably more flexible device?
PCI Express on the Raspberry Pi 4
101–110 of 166 posts
Re: PCI Express on the Raspberry Pi 4
#102Earlier quoted context omitted.
The Pi4 isn't PCIe Gen 4, though. It's only PCIe Gen 2. Max speed of PCIe Gen 2 is 5GT/s, which equates to the same speed as standard USB3.0/USB3.1 Gen1/whatever its called nowadays.
Nyqist frequency of 2Ghz for PCIe 2 (slightly less in practice due to line code) is still nothing to sneeze at.
2.5 GHz, actually. Obviously there's limitations and you have to be careful, but it's not too crazy to think you could use a piece of USB3 cabling to do this. Requires some pretty precise soldering skills though.
Re: PCI Express on the Raspberry Pi 4
#103Earlier quoted context omitted.
I've seen pcie literally run over a metal clothes hanger soldered to the board. It's extremely tolerant of terrible quality connections.
How did you reach the situation where the solution was soldering a clothes hanger to a board for pcie ???
Putting shirts directly onto the board creates heating issues
Re: PCI Express on the Raspberry Pi 4
#104Interesting install a SATA card and make a NAS. I think better than a usb.
What makes it better than USB for this purpose?
Re: PCI Express on the Raspberry Pi 4
#105Earlier quoted context omitted.
Wouldn't the gigabit LAN be a better fit for this? If you want to make a cluster, you need to make some custom hardware to connect to, that can facilitate the communication. At this point you're likely spending more that if you just bought a real desktop for more performance. I can see the fun factor in hacking the system together, though.
There are two ways of doing clusters - one is a message passing paradigm, which you can do over Ethernet (to an extent - I’d still take USB3 for 4x the bandwidth) - and the other is direct memory access a’la Cray. What really motivated me to do this hack is the relative abundance of stuff I can now plug into an FPGA :)
I suggest the RoarVM message passing Smalltalk Virtual Machine [1][2]. Erlang/OTP with actors would be my second choice.
[1]Ungar, D., & Adams, S. S. (2009). Hosting an object heap on manycore hardware. https://sci-hub.tw/10.1145/1640134.1640149
[2]RoarVM demo https://www.youtube.com/watch?v=GeDFcC6ps88
Re: PCI Express on the Raspberry Pi 4
#106If a Pi is capable of this already, why not replace the Ethernet, charging, micro-HDMI, and USB ports with a boatload of type-C Thunderbolt ports (plus support for the HDMI 1.4 alt mode)? Would 8xUSB-C cost that much more than 1xUSB-C+1xEthernet+2xMicro-HDMI+2xUSB3+2xUSB2 (with no PCI Express), in exchange for a considerably more flexible device?
Considering the fact that 1 USB C Thunderbolt port can power a dock that could do multiple HDMI, Ethernet, USB, VGA, etc, I agree completely and I hope that they release a Raspberry Pi4C.
Re: PCI Express on the Raspberry Pi 4
#107If a Pi is capable of this already, why not replace the Ethernet, charging, micro-HDMI, and USB ports with a boatload of type-C Thunderbolt ports (plus support for the HDMI 1.4 alt mode)? Would 8xUSB-C cost that much more than 1xUSB-C+1xEthernet+2xMicro-HDMI+2xUSB3+2xUSB2 (with no PCI Express), in exchange for a considerably more flexible device?
Because people do not want to deal with gazillion dongles
Re: PCI Express on the Raspberry Pi 4
#108If a Pi is capable of this already, why not replace the Ethernet, charging, micro-HDMI, and USB ports with a boatload of type-C Thunderbolt ports (plus support for the HDMI 1.4 alt mode)? Would 8xUSB-C cost that much more than 1xUSB-C+1xEthernet+2xMicro-HDMI+2xUSB3+2xUSB2 (with no PCI Express), in exchange for a considerably more flexible device?
A lot of the benefit of the rpi is the built in IO. Would the rpi still be cost effective without it? Not for many of the IoT projects that make the rpi so popular.
Re: PCI Express on the Raspberry Pi 4
#109That's really cool. I'm curious, would it be possible to use a modern GPU (running at 1x) on an ARM based board? Would the open source drivers that are part of the Kernel work out the box on ARM?
If you want it for ML you could check out the Coral TPU. (Tensor Processing Unit over USB) I picked up a couple of those yesterday.
Re: PCI Express on the Raspberry Pi 4
#110If a Pi is capable of this already, why not replace the Ethernet, charging, micro-HDMI, and USB ports with a boatload of type-C Thunderbolt ports (plus support for the HDMI 1.4 alt mode)? Would 8xUSB-C cost that much more than 1xUSB-C+1xEthernet+2xMicro-HDMI+2xUSB3+2xUSB2 (with no PCI Express), in exchange for a considerably more flexible device?
A lot of the benefit of the rpi is the built in IO. Would the rpi still be cost effective without it? Not for many of the IoT projects that make the rpi so popular.
A RasPi-compatible USB GPIO breakout adapter would be a cool product.