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Putting out the hardware dumpster fire

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Re: Putting out the hardware dumpster fire

#101

Post by snvzz »

dezgeg wrote: post #60
AnthonyMouse wrote: post #56

Earlier quoted context omitted.

> Why we need a dedicated CPU and DRAM attached to flash memory. You can garbage collect and wear level in your OS if you want to. The thing I don't get is, the chips are all commodities, and it's not like soldering them to a board is rocket science. Why isn't one of the companies that makes fully-specified inexpensive RISC-V chips selling one attached to some commodity flash chips and an NVMe connector? Include some…

For starters, I doubt that acting as a NVMe device is something you can do with a off the self "inexpensive RISC-V" with any kind of acceptable performance. A NVME engine would almost certainly be something that the flash controller would have implemented in fixed function hardware. Also NAND flash practically requires some sort of error correction system - another thing that fixed function logic in a custom ASIC is…

>RISC-V in charge of NAND storage, presenting NVMe (or SATA) interface.

Aren't WD SSDs just that?

Re: Putting out the hardware dumpster fire

#102

Post by dezgeg »

snvzz wrote: post #101
dezgeg wrote: post #60

Earlier quoted context omitted.

For starters, I doubt that acting as a NVMe device is something you can do with a off the self "inexpensive RISC-V" with any kind of acceptable performance. A NVME engine would almost certainly be something that the flash controller would have implemented in fixed function hardware. Also NAND flash practically requires some sort of error correction system - another thing that fixed function logic in a custom ASIC is…

>RISC-V in charge of NAND storage, presenting NVMe (or SATA) interface. Aren't WD SSDs just that?

No, they are not just a converter that exposes raw NAND to your PC. Rather they abstract away all the details of how painful raw NAND is to deal with into simple "read/write sectors" interface that all your normal filesystems like ext4, NTFS, etc. deal with.

Raw NAND comes with various pain-in-the-ass limitations such as: only erasable in huge (~megabytes) blocks at a time, only writable in slightly-uncomfortably-big chunks (like 32KB or so), and erasing a given region can be done a limited amount of times before it breaks. Oh, and all those details (like exact sizes of erases and writes) will change time to time as manufacturing processes of NAND dies get more advanced.

Re: Putting out the hardware dumpster fire

#103

Post by dezgeg »

AnthonyMouse wrote: post #89
dezgeg wrote: post #60

Earlier quoted context omitted.

For starters, I doubt that acting as a NVMe device is something you can do with a off the self "inexpensive RISC-V" with any kind of acceptable performance. A NVME engine would almost certainly be something that the flash controller would have implemented in fixed function hardware. Also NAND flash practically requires some sort of error correction system - another thing that fixed function logic in a custom ASIC is…

The basic function of transferring data between the flash chips and the PCIe bus shouldn't be a bottleneck. Dedicated silicon for error correction might be more efficient, but when there are already fast idle CPU cores it may not matter, and ECC algorithms can already be accelerated by SIMD instructions. Or for high performance machines add the dedicated silicon to the host CPU.

These kind of high speed interfaces aren't just something that one just bitbangs on some microcontroller.

I think even the first step, ie. finding a RISC-V chip that has capability of acting as a PCIe device at all will be a challenge. "Inexpensive" for sure not.

Re: Putting out the hardware dumpster fire

#104

Post by AnthonyMouse »

dezgeg wrote: post #103
AnthonyMouse wrote: post #89

Earlier quoted context omitted.

The basic function of transferring data between the flash chips and the PCIe bus shouldn't be a bottleneck. Dedicated silicon for error correction might be more efficient, but when there are already fast idle CPU cores it may not matter, and ECC algorithms can already be accelerated by SIMD instructions. Or for high performance machines add the dedicated silicon to the host CPU.

These kind of high speed interfaces aren't just something that one just bitbangs on some microcontroller. I think even the first step, ie. finding a RISC-V chip that has capability of acting as a PCIe device at all will be a challenge. "Inexpensive" for sure not.

There are RISC-V chips with PCIe controllers on them. I'm not sure if you can use the hardware designed to act as a host to act as a device, but it wouldn't surprise me. In any case I would find it hard to believe that the hardware that can act as a device would cost significantly more.

You can get a whole NVMe SSD for $15:

https://www.newegg.com/silicon-power-128gb-p34a60/p/N82E1682...

The hardware required to do this can't be that expensive.

Re: Putting out the hardware dumpster fire

#105

Post by isityouyesitsme »

Hermitian909 wrote: post #39
nightowl_games wrote: post #9

I like the boldness of the title and the simple clarity of the writing. Academic papers are frustrating to me in that they seem to use esoteric language in order to create a veneer of importance, sometimes above trivial real content. This stands against that trend and harkens back to papers of old.

> they seem to use esoteric language in order to create a veneer of importance, It's kind of true, but also I think the real answer is that you're not the target audience. A lot of time you use esoteric language because part of the problem being solved for in these conversations are: 1. what are useful and meaningful abstractions? 2. which abstractions are seeing uptake? 3. Who gets credit for the abstraction? This m…

Nah.

Nobody complaints when you invent words or phrases to add clarity, but most academic papers are NOT doing this. It's an academic circle-j** where all the authors play the same game to try to fit in with each other.

And in this respect, you're 100% right. Professionals who make a living doing work, even the ones who know more about the topic than the researchers, are not the target audience. The target audience is the others participating in the circle-j** who determine if the paper should be published.

And no, I'm not saying that researchers are worthless and don't know anything. Merely that they have different purposes and standards for their work. And it has always been this way, in every field.

Re: Putting out the hardware dumpster fire

#106

Post by AnthonyMouse »

dezgeg wrote: post #102
snvzz wrote: post #101

Earlier quoted context omitted.

>RISC-V in charge of NAND storage, presenting NVMe (or SATA) interface. Aren't WD SSDs just that?

No, they are not just a converter that exposes raw NAND to your PC. Rather they abstract away all the details of how painful raw NAND is to deal with into simple "read/write sectors" interface that all your normal filesystems like ext4, NTFS, etc. deal with. Raw NAND comes with various pain-in-the-ass limitations such as: only erasable in huge (~megabytes) blocks at a time, only writable in slightly-uncomfortably-big…

That's software, not hardware. And operating systems have long dealt with things like variable sector sizes. You want the abstraction layer. What you don't want is for it to be a black box, and what you shouldn't care about is whether the silicon that runs the code is soldered to the flash chips or not.

Re: Putting out the hardware dumpster fire

#107

Post by mathisfun123 »

isityouyesitsme wrote: post #105
Hermitian909 wrote: post #39

Earlier quoted context omitted.

> they seem to use esoteric language in order to create a veneer of importance, It's kind of true, but also I think the real answer is that you're not the target audience. A lot of time you use esoteric language because part of the problem being solved for in these conversations are: 1. what are useful and meaningful abstractions? 2. which abstractions are seeing uptake? 3. Who gets credit for the abstraction? This m…

Nah. Nobody complaints when you invent words or phrases to add clarity, but most academic papers are NOT doing this. It's an academic circle-j** where all the authors play the same game to try to fit in with each other. And in this respect, you're 100% right. Professionals who make a living doing work, even the ones who know more about the topic than the researchers, are not the target audience. The target audience i…

>Professionals who make a living doing work, even the ones who know more about the topic than the researchers, are not the target audience.

You know what's the shittiest spot to be in? A PhD student that's also one of those working class professionals. Can you imagine working on something you know represents a significant technical challenge in industry and then writing a paper on it and then it get rejected because it's "just engineering".

My personal favorite (ie in my area) is the original pytorch paper isn't publishable for this reason (but simultaneously is the highest cited - through it's arxiv orcid - ML compiler paper of all time).

Re: Putting out the hardware dumpster fire

#108

Post by yafbum »

ThreeFx wrote: post #40
yafbum wrote: post #30

I'm not sure what fire has been put out here. IMO, a more convincing proof for the usefulness of this approach would be that it allows to find whole new classes of exploitable vulnerabilities that can then be corrected ahead. That's how static code analysis tools typically demonstrate their value. Without such proof, the description that they make of a hardware platform is mentally interesting but not clearly useful.

I think there’s potential for a second-order effect here: generate enough vulnerabilities and SoC designers will start to put it out themselves.

Absolutely. Fire won't be put out unless someone shows exactly how much there is...

Re: Putting out the hardware dumpster fire

#109

Post by isityouyesitsme »

mathisfun123 wrote: post #107
isityouyesitsme wrote: post #105

Earlier quoted context omitted.

Nah. Nobody complaints when you invent words or phrases to add clarity, but most academic papers are NOT doing this. It's an academic circle-j** where all the authors play the same game to try to fit in with each other. And in this respect, you're 100% right. Professionals who make a living doing work, even the ones who know more about the topic than the researchers, are not the target audience. The target audience i…

>Professionals who make a living doing work, even the ones who know more about the topic than the researchers, are not the target audience. You know what's the shittiest spot to be in? A PhD student that's also one of those working class professionals. Can you imagine working on something you know represents a significant technical challenge in industry and then writing a paper on it and then it get rejected because…

I'm purely curious at this point, I have nothing else to add here---what's your favorite example of the other failure, the type where all the researchers in the industry hype something and then 10 or 20 years later, you can look and say "well, that was a swing and a miss..." ?

Re: Putting out the hardware dumpster fire

#110

Post by mathisfun123 »

isityouyesitsme wrote: post #109
mathisfun123 wrote: post #107

Earlier quoted context omitted.

>Professionals who make a living doing work, even the ones who know more about the topic than the researchers, are not the target audience. You know what's the shittiest spot to be in? A PhD student that's also one of those working class professionals. Can you imagine working on something you know represents a significant technical challenge in industry and then writing a paper on it and then it get rejected because…

I'm purely curious at this point, I have nothing else to add here---what's your favorite example of the other failure, the type where all the researchers in the industry hype something and then 10 or 20 years later, you can look and say "well, that was a swing and a miss..." ?

Uh I'm not a pundit or historian or whatever but I don't think this is possible except in a negative externalities sense (PFAS, climate change, etc). If you hype something in industry and it doesn't work then you or your company get fired (or something like that). While in academia you can write a paper that "proposes" or is "toward" something or has an implementation in the grad student's personal dialect of whatever language (ie shit code). Granted shit code abounds in industry too but at least in industry someone is going to review some aspect of the implementation before, during, or after it ships.
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