CXL in Next-gen Servers Will Make Today's Servers Obsolete

[@beauslim]

This is, by far, the most effort I have ever seen someone put into expensing lunch.

[@lxnny2357]

That's hilarios.

[@dustinphillips605]

I don't think the taco, lime, "soda" mechanism made it easier to understand. But I do fully support this if it was used as a justification for getting delicious tacos.

[@ServeTheHomeVideo]

Great analysis :-)

[@dktol56]

Sadly, Rubios succumbed to the pandemic in my town :-(

[@cdoublejj]

I thought that too and got lost BUT, at the end with with only get one lime plus the beer made so much more sense. Basically it's just resource sharing whether they're on the host or not

[@DivaAnnFisher]

What junk. How does this guy make a living with such gibberish?

[@rem9882]

From your explanation, you've pretty much said I need to get some tacos

[@ServeTheHomeVideo]

I did this a few days ago... and I feel like I need tacos again.

[@wmopp9100]

I understood CXL up until the lime analogies started

[@ReQuiem_2099]

I’m really loving the extra effort put into the STH channel and think that you guys get criminally under appreciated. There is so much half-assed crap out there playing the KZbin algorithm game with little to no added value to the community. Hoping for bigger view counts, etc. but mostly just do you and know you’re appreciated!

[@Warrigt]

criminally?! good luck with that suit.

[@jolness1]

@@Warrigt It's an expression. You must be fun at parties.

[@michalpbielawski]

When life gives you limes, make some weird server hardware analogies

[@ronaldmcdonald3965]

you have a future in comedy

[@Sirus20x6]

sometimes the best analogy is not to use any analogy, but just explain the technology straight up without abstractions

[@HydraulicDesign]

This comically tortured analogy is awesome.

[@PoeLemic]

Yeah, it was a little of a stretch, but he expenses off a big lunch ... I bet ... he he he ...

[@ttb1513]

If he had used lemons more instead of limes, I would have soured on the analogy.

[@vld]

Technical content is great. Drop the limes. Cute, but gets in the way.

[@stevetaylorftw]

For me, the lime metaphor made it harder to understand. I applaud the effort, but would appreciate a non-lime version.

[@karimmanaouil9354]

Same. It was unnecessary.

[@MarcDoughty]

I can see CXL being very useful in consumer hardware. Imagine a CPU with 8GB of very fast RAM on the package and a CXL bus to expandable memory. Imagine rethinking 'vram' 'swap' and 'hibernate' entirely by tiering memory between the on-package, expandable, and storage-backed options over a CXL bus.

[@axe863]

Machine learning applications are insane. There's a new field of ML using Semi-Randomized sparse ReLUs feature expansion with sparse linear regularization. The Semi-Randomized sparse ReLUs feature expansion approaches Deep Neural Networks with the sparse linear regularization weeding out shitty features in a very fast manner. It's insanely RAM intense but, by circumventing costly nonlinear optimization, for more computationally inexpensive.

[@VraccasVII]

What does the security side of this look like? This sounds amazing, but die idea of every device sharing the same memory also sounds like an attack vector Excellent explanations by the way

[@creker1]

The standard supports encryption and data integrity. All communication between devices can be AES encrypted with integrity checks. The threat model mainly covers sniffing on the bus and injecting something. It also mentions replacing devices with malicious one's but it doesn't cover how exactly it protects against that. Public keys are not in the scope of the standard and key exchange looks to be dynamic.

[@Cynyr]

@@creker1 I think the bigger issue here is how do you control what memory can be accessed by each device. I'm sure the idea here is to limit the copies between devices as well, CPU to nic: "Here's a memory address, send XYZ number of bits down the network cable please. NIC: sure thing, but don't pay any attention to me reading XYZ+256bits... CPU:???

[@creker1]

​@@Cynyr that's outside the scope of the current standard. I don't think they will try to cover it. It explicitly says that all the connected devices are in the trust boundary and it doesn't cover badly implemented devices. The only thing it covers is sniffing and injecting data while it travels between devices and swapping devices with malicious ones. You can always use other techniques to further protect the communication. Like IOMMU. It allows CPU to map a part of its memory to certain virtual address space that a device can access. That way it can't read some random address like you can with regular DMA. Device can't just go and read CPU memory. It has to through memory controller.

[@creker1]

@@BrianStewart126 what else can they do? CXL is an interconnect. It can only protect what goes over it. Like HTTPS protects your from eavesdropping but can’t protect you from site making attacks against you. CXL mainly reuses what PCIe IDE provides and it also doesn’t cover anything beyond inflight data encryption and integrity. They also can’t do anything beyond that. If you can’t trust devices then maybe don’t put them into your servers? You have to have trust boundary somewhere.

[@Waitwhat469]

@@creker1 is the interconnects between devices managed by the host, or is it more like an open switch? If controllable then you could limit connects between difference devices (the big reason I see this being useful is more so getting closer to trustlessness in vms and containers, where you could adjust what can use certian devices based on what is currently using them so say process A and B is ran by one tenet, but process C is ran by another You may trust the hardware, but when tenet 1 is running on the hardware and given some control of it, this break the trust boundary of tenet 2, but you don't want to limit the number of process that can be ran on them to 1 as that would mean you would need to double the hardware to run tenet 1's workload. With proper tagging, though, you could, like you can with entire nodes in kuberenetes, taint hardware and only allow some process to schedule to them based on acceptable taints.

[@colonelangus7535]

I get a kick out of the range of people doing wonderfully thought out and informative youtube videos. Craft Computing, "Let's mix a double strong cocktail during the video" Serve The Home, "The lime goes in the soda" :) Looking forward to 2028 when I can afford servers from 2022 with this tech.

[@firworks]

"So what if we take that lime that's in our *host taco* and utilize that lime juice for our beverage."

[@suntzu1409]

STONKS!!!!!

[@tinfever]

In order to understand CXL, we will be using a hypothetical perfectly spherical lime. Implementation using non-spherical limes or other fruits will be left as an exercise for the reader.

[@SchoolforHackers]

Or chicken. Yes.

[@ArchaeanDragon]

CXL.io is essentially the out-of-band signaling for setting up, configuring, discovery, and tear-down of CXL devices, while CXL.cache/CXL.memory are the in-band transfers and communication of actual data.

[@andrewwong2000]

Now I get where I've been going wrong all this time. Lime goes in the Taco, not the Soda

[@MrBikeagraman]

"Soda" has food value, but food has no "soda" value.

[@Night_A]

This sounds a lot like those "Server on a Chip" (or module) concepts from several years back. Do you think this might lead to a form of mainframes making a comeback in the general market?

[@3dduff]

I am dealing with servers as part of my render farm for render nodes as well as storage. The HUGE revelation I had listening to your lime example is Video ram. we are sometimes limited on what we can render all in one frame. A centralized CXL changes all of that because it would be all SYSTEM memory and the GPUS would draw out what they need. and in speaking of memory pools, This would be huge for the simulation side too. Simulations can take up hundreds of gigs a list space making their simulation caped at what the CPU or GPU can handle on one task, CXL could lift that limit. and speaking of limits keeping that rendering and simulation data LIVING in a centralized location, accessible to multiple computing devices would have a huge impact on speed. I'm sure it's going to take a few years for the hardware to trickle down to studios like mine, but I would not be surprised to see a whole range of new software that is made to exploit this new technology. But this sounds familiar....how does this compare to HP's original vision for their ProLiant servers?

[@NTmatter]

20:55 Following the metaphor, the DPU would encapsulate the lime in a coconut for permanent storage. Given the latency involved, would this process end with a callback telling the processor what to do?

[@CrazyLogic]

Super - does this mean that in the future, with multiple CXL connected processors, RAM, and other devices, that we'll be heading back towards 'mainframes' where everything is essentially run on one self consistent host rather than say a cluster of hosts with a few NUMA nodes each? Is it similar to how IBM does it's Z mainframe? Can you imagine how much compute power a cluster/swarm/mainframe will have if you took any number of cs-2's from Cerebras, and CXLed then with say 1000 EPYC 64 core... Just mind boggling.

[@ServeTheHomeVideo]

Mainframes are a bit of a different game, but there are key concepts especially as next-gen servers scale (a lot)

[@creker1]

CXL is about node-level, connecting devices inside a single server. What you're thinking is Gen-Z which is about taking that idea and stretching it between nodes. But even then, no, I really don't think we will have illusion of rack or multiple racks working like a single host. Maybe we will have NUMA division where scheduler is very careful about migrating workloads between nodes. It's simple physics. Inter-node latencies are too big to simply treat it as a single box. You will always have to think about it and make necessary optimizations to keep data local to compute and go over fabric only when absolutely necessary.

[@CrazyLogic]

@@creker1 totally agree with latency issue, but even if they are split time domains/NUMA nodes, CXL looks to be a lower overhead for node to node, rather than IP or infiniband ect. The future looks fast :)

[@creker1]

@@CrazyLogic CXL probably can't scale beyond one server simply due to protocols. If we look at Gen-Z, they don't use ethernet or infiniband but they did implement something similar to them. To build a node-to-node fabric you need to be able to route packets, address many devices, handle failures (optics can and will fail). That's why Gen-Z comes with a whole bunch of infrastructure hardware - bridges, switches, gateways.

[@davidtolley1374]

Crushed (squeezed?) it with the lime analogy. Made sense to me. Great video.

[@scheimong]

I'm honestly super eager to see this technology mature and propagate down to the consumer market. Combined with the recent push for right to repair, it will surely make PC upgrading a much more practical and appealing option.

[@creker1]

CXL brings nothing that would benefit right to repair. PCs are already extremely practical and upgradable. There's nothing to gain there.

[@Nobe_Oddy]

That was a pretty good analogy... I think lol - I'm pretty sure I understand what CXL is, well the basics of it... When I first saw the limes on to of the camera, where the light would be, I thought you were gonna say 'It's time for CXL to be in the LIMELIGHT!" lol :D

[@Banner1986]

I'd try making analogies to networking for for explanations like this, where trying to explain either a protocol/communication methodology - for instance, how does something know that something else has cxl available? Broadcast advertisement. Etc. Most folks in the IT world I'd think would have enough understanding of networking to make quick and easy sense using such an analogy, and it's easy to lose track when taking something completely unrelated. Especially when hungry. I feel like I understand cxl pretty well, but I'm starving and had to watch it a few times to make sure I could follow where you were going with it.. kept thinking "man... chicken tacos sound soooo good right now..." 😅

[@1funnygame]

I hope this fixes the large amounts of ram assigned to you when you use high end CPU's in the cloud. Will hopefully lower costs for compute intensive workloads

[@PrestonBannister]

The local Rubios thanks you for your product placement. :)

[@d-fan]

brb, plugging a lime wedge into my RAM slot

[@vtr8427]

Wonderful man this talk you paced yourself well . 👍

[@PpVolto]

My CXL Analogie: You have a Connector Board, a 64GB DDR5 Ram Board, a x86 CPU Board and a Arm CPU board the CPU boards only have 1GB to Function. Now your x86 board needs 16 GB Ram and request that from the Memory Board at the same time the ARM Board uses 32 GB Ram on the same Memory Board. Now you add a GPU Board with 8GB Ram but the GPU needs more it requests aditional 16GB ram from the Memory board. The next step ist the GPU need more Ram and you add a Second 64GB Ramboard now your GPU can Request 32 GB Ram and it switches with the full 32 GB to the new Memoryboard or only request 16 GB additional Memory from the new Board. The second scenario is You add a GPU Board with 128GB Ram but your GPU only needs 12 GB now your x86 CPU board can request 64 GB ram from that GPU board, now you add a Second GPU Board with 256GB of Ram and that GPU needs 300 GB Ram the first 256GB are on board and the 44 GB are on the first GPU.

[@mamdouh-Tawadros]

Thank you for the clarification. But my question is that not all memories are made equal, so the presumed pool is a mixture of varying memory speeds, latencies, and generations.

[@ServeTheHomeVideo]

You have to think of next-gen servers as much larger. Core counts, TDP, and I/O go way up. So even if CXL has more latency than a host DDR5 controller, it is still useful if it gets you a larger pool of memory in a system.

[@creker1]

Yes, CXL does cover that. There's whole QoS, back pressure, credit system and other stuff. Also different memory pools can expose through ACPI tables the exact latency and bandwidth so that the system can appropriately schedule and balance workloads between them. For any performance sensitive workload it just doesn't work as a simple unified memory pool.

[@creker1]

@AstroCat devices will always have their own caches. It just doesn't work any other way. What CXL allows is keeping these caches coherent with various memory pools. For complex devices it will be done completely in hardware and will be transparent to the software. Like GPUs. They will always have multiple levels of cache and private memory pool. CXL can't and will not change that.

[@mlaubenthal]

I love the tacos and lime analogy!

[@naikrovek]

We speak tech, man. You don't need analogies. This lime thing made it harder to understand, for me. Lime juice is only used once. Memory is reused.

[@chromerims]

I'll play . . . after peak deployment of CXL in the future, there well could be a reactionary trend to revive and mix in a sprinkling or more of onboard, "un-disaggregated" memory . . . to achieve greater performance and even more robust (possibly battery-backed) persistency. Excellent video 👍 Kindest regards, friends and neighbours.

[@C3Cooper]

I wonder how long it will take before someone designs a cache/side-channel attack.

[@capability-snob]

I need to find out if layering over pci-e has kept the protocols capability secure. That's going to be a fun fishing exercise.

[@ServeTheHomeVideo]

Check out the CXL 2.0 security features including encryption.

[@tanmaypanadi1414]

I wish we had a wild Wendell dropping by in the videos 😉

[@BoomChockolaca]

Great example with limes and "sodas", I really love the personal touch you've adding in the last videos! Aaaand, yeah, now I want some "soda" too :)

[@youtubecommenter4069]

"That DPU could manage the flashing of the persistent memory", 21:05? If the PMEM is already CXL, why do that? Wouldn't it be better to build an on chip controller on server class CXL PMEM instead of sending flash back to NAND?

[@robertharker]

Great video. I liked the limes. But what about habanero peppers and avocados? Or fajitas and burritos? How will CXL integrate them?

[@ServeTheHomeVideo]

I have never tried habanero peppers in a "soda" but I imagine someone has.

[@robertharker]

@@ServeTheHomeVideo As with all things, some people think about the sodas, some people think about the food. Each to their own and better yet when they share.

[@AI-xi4jk]

Those “sodas” are waiting impatiently for the filming to be over.

[@ServeTheHomeVideo]

Some tacos did not make it until filming was over.

[@rjdp3]

Next- ServeTheFood opens! Seriously, thanks for the food stretch

[@MourningLobster]

Great explanation 🤠. Subbed 👍.

[@ServeTheHomeVideo]

Thanks for the sub!

[@Openspeedtest]

So My next server need some lime, soda and tacos to run.

Have you kept the C70 alongside this nice FX3?

[@ServeTheHomeVideo]

This was filmed on the C70. I wanted to use the FX3 as a lighter mobile camera.

[@KenHihihi]

holy shit, you explained perfectly ! hope this new technology will implemented very very soon

[@thomasbonse]

I think a hotpot would've been a more appropriate metaphor for csx.

[@youtubecommenter4069]

Hey Patrick, nice explanation, 6:29. Do you see NVMe M.2 SSDs now at PCIe x 4 remaining so or will these do PCIe x 2 with Gen 5.0/ CXL "to free up CPU lanes" as per the dead cool fact you dropped, 6:44?

[@creker1]

M.2 are being fazed out of server market. EDSFF is going to replace it and there x4 would be the minimum. It doesn't really makes sense to reduce lane count. PCIe drives scale with new PCIe versions and people need all the performance they can get. And it's just simple to do it that way for compatibility.

[@lost4468yt]

Is this why PCIe 5.0 is coming out so quickly after PCIe 4.0? The time gap seems much smaller than between previous generations.

[@ServeTheHomeVideo]

CXL is one reason. The bigger reason though is that I/O was severely bottlenecked with PCIe Gen3. A hyper-scaler can do a 400GbE NIC in a PCIe Gen5 x16 slot as well which will help with next-gen systems. PCIe Gen6 will be a quicker transition as well.

[@creker1]

@@ServeTheHomeVideo I always wondered, why are we still limited to 16 lanes on PCIe? Yes, there're some proprietary wider ports and standard does support x32 but actual hardware is still stuck at x16. Looking at how NVLink scales to ridiculous speeds it feels like PCIe is intentionally crippled by that with no good reason.

[@ServeTheHomeVideo]

NVLink uses a TON of power. We did the 8x P100 but then saw a big jump on the 8x V100 machine. On the 8x A100 machine we have in the lab now, same story.

[@lost4468yt]

@@ServeTheHomeVideo Oh right very interesting. Do you know what tech is used for the submarine cables? E.g. the Marea cable can transfer at 26.2 terabits/s, with 8 pairs of fibres inside of it. That's 3,275 gigabits/second in a single strand of fibre. What do they use for those? FPGAs? ASICs?

[@edouard1580]

Isn't this going to put more strain on the memory bandwidth? Since CPUs spend a lot of time waiting for host memory data to come it seems like CXL could make this problem worse.

[@ServeTheHomeVideo]

In some ways. Something many folks underestimate is just how much effort is being spent on next-gen I/O.

[@ElijahPerrin80]

I wondered if this would ever happen, thank you.

[@PanduPoluan]

That "soda" looks mighty sus... 🧐 I think that's an Impostor!

[@nobodyspecial7097]

I’m drinking a Dogfish Head 120 Minute “soda” watching this

[@semosesam]

Damn, those tacos looked amazing...

[@ServeTheHomeVideo]

They were very good. It was also very hard to let them just sit there to take the photos/ b-roll.

[@PoeLemic]

I really loved this overview. Helps me understand this in an overview fashion. Also, I love using analogies, and I laughed at how you used it. Very good work. You're a Teacher at heart.

[@IAMSolaara]

I recently rewatched the IBM POWER10 video and I remember hearing something similar to this. Am I correct?

[@ServeTheHomeVideo]

Yes. There is a quick mention of OMI in here. The big difference is that this is what the industry is doing, IBM just was in front doing its own thing.

[@creker1]

Yep, CXL is very similar to PowerAXON/OpenCAPI

[@SinisterPuppy]

And with one video my home lab feels inadequate. Thanks for the video; can't wait to see what performance improvements CXL will provide.

[@p3chv0gel22]

Ha. My homelab can't feel that way Because it doesn't exist (cries in salary of an it trainee)😅

[@zrodger2296]

The problem with this is that I think the lime transferred some beer into your taco! (Though maybe that's not a bad thing.) 😏

[@filovirus1]

I imagine CXL implementation for PC: need more CPU? buy cores incrementally; need more memory? buy more and add them hot-swap; need more GPU? same story plus no more HDD because everything is persistent. and run multiple different OS simultaneously on the same physical system - in effect, I become my own hyperscaler and open for business!

[@MisterRorschach90]

It’s crazy to think that in 1-2 years they will have high end consumer motherboards with pcie gen5, they will probably have built in 25,40, or even 100gbe nics on the prosumer stuff. They will have bandwidth for multiple usb4 40gbps ports or usb5 if that comes out. And we will potentially have nvme drives that push 14gbps read and write. I hope intel does something with optane on the prosumer and consumer side for gen5. Seems they only have super expensive server stuff for gen4. It is stupid fast and reliable though.

[@ServeTheHomeVideo]

Probably not 100GbE NICs onboard on the prosumer side. The challenge there is really just the fact one would need to go fiber and most prosumers do not have the network switches/ devices for 100GbE. Power per bit goes down, but overall power goes up with 100GbE as well.

[@swyftty2]

Lets hope our 6x ram devices expand to more server devices for cxl than just gpu's

[@amateurwizard]

This has the potential to be HILARIOUS, skip to half way without the context of the first half. I don't mind watching it 1.5x...You're welcome! 👍

[@iham1313]

now i want shrimp-taco-cxl's!

[@ServeTheHomeVideo]

Tacos de camarones!

[@speckblue]

I'm just here for the tacos.

[@suntzu1409]

This thing hodls great potential

[@Felix-ve9hs]

_limes_

[@LiraeNoir]

I had some basic understanding of what CXL was. Then I listened to 5 minutes of lime analogy, and now I'm thoroughly confused...

[@CheapSushi]

Gotta go eat a taco right after to truly know.

[@gfeie2]

This channel makes me so happy :)

[@conquerordie230]

Thank you for making this explanation approachable for the layman. How do you see this technology affecting Resizable BAR (is that even a good analogy?)?

[@hgbugalou]

Instructions unclear. I now have tortillas jammed in my DIMM slots and a lime skewered on a heat pipe.

[@jdl3408]

Now I have to go to Rubio’s this weekend…

[@bronekkozicki6356]

Here is a man who likes his tacos with lime juice.

[@MoraFermi]

So it's essentially SAN 2.0, with the difference that devices may simultaneously provide and consumer resources.

[@Allyouknow5820]

And... I'm thirsty for a "soda" now :D I remember a time when one could enjoy a "soda" with friends.

[@ServeTheHomeVideo]

I was in Phoenix, AZ and Nashville, TN last week(end). While I'm fully vaccinated, people there are enjoying sodas with friends without masks everywhere I looked.

[@creker1]

I really doubt that SSD example will actually be implemented. I just don't see the point. SSDs need DRAM (if we're talking about something fast and not slow QLC or something for cold storage) and they need it to be very close due to latencies. CXL is simply gonna be too slow and cause too much overhead. We already saw this with Linux IO scheduler that only causes bottlenecks with NVMe. And that's CPU with its own RAM without any CXL fabrics. That's the same reason we have multiple levels of cache. It's a necessary optimization. What's actually much more relevant example, I think, is CXL being cache coherent interconnect for various compute resources. Servers already have ML processor, GPUs, CPUs, FPGAs and usually all of them work on the same task. They need to communicate and share data. Right now everyone uses different home-grown solutions to tackle this - Google TPUs use DMA engines and HBM with some weird interconnect; NVIDIA uses nvlink; AMD uses infinity fabric. FPGAs don't have anything at all, I think. All of these will be replaced by standard CXL fabric that will actually make everything interoperable. Intel already planning to use CXL as an interconnect between their Xe GPUs just like NVLink. But even then we will have the same problem - it's too slow to go over CXL to read or write someone else's memory. Like always software and hardware will try to keep everything in their local RAM as much as possible and utilize CXL fabric only to transfer necessary data. I also think we can't talk about CXL without mentioning Gen-Z. With recent partnership it completes the whole picture and stretches that coherent interconnect to datacenter scale. The dream about having boxes of CPUs, GPUs, FPGAs, NVMe all in separate racks and being able to provision them independently will finally come true.

[@ServeTheHomeVideo]

The write cache on SSDs that is power-loss protected is designed to enable fast/ safe sync writes. Writing to SCM/ Optane provides that while allowing time to flush to NAND at a slower pace, but also multiple NAND devices potentially beyond just a single machine. That model is already in production using Optane so it is a stretch, but one that is already deployed using existing technology. You are totally right about GenZ as well as accelerators. Accelerators are going to be the leading edge in CXL 1.1 devices next year.

[@creker1]

@@ServeTheHomeVideo that's not the only reason SSDs need DRAM. Probably the main one is RAM for controller to store mapping tables. Without that and going over CXL they gonna be severely crippled. As for write cache, yes, that works and already in production. But it feels like moving the problem to a different place and not solving anything fundamental. You get cheaper SSDs, yes, but you then pay enormous money for optane. Not much of a gain IMO. What Optane brings to storage solutions is very low latency write cache, as you said, that you simply can't get with any NAND SSD. That's the value, I think. But then again, we don't need CXL for that.

[@MatthewHill]

So... only five or six years before this lands in my homelab and starts accelerating my Plex server and my NAS.

[@tommihommi1]

idk, the whole re-sizeable BAR hype we just had for consumer GPUs basically is a predecessor to what this technology could bring. The next gen of consumer CPUs and GPUs implement PCIe 5, after all. The dramless SSD argument also works for consumers.

[@maxhammick948]

So hypothetically: we could have some CXL-enabled device that accepts a few m.2 ssds; then plug an m.2 to standard PCIe slot adapter into that; then plug a PCIe to usb expansion card in that; which will finally enable us to use the hard drive on a first gen ipod as system RAM? This calls for celebratory tacos 🌮🌮🌮🍋

[@ServeTheHomeVideo]

One of the next videos will be on how in the next-gen servers U.2, U.3, and M.2 are going away

[@kickbul]

Came to learn about a cool new technology, left hungry!

[@hariranormal5584]

What is the camera with the fruits on top xD

[@ServeTheHomeVideo]

Sony FX3 with a 24-70mm f2.8 Sony G Master lens. That is what I used for the TinyPilot Raspberry Pi video kzbin.info/www/bejne/omjMXpujlKplotU

[@hariranormal5584]

@@ServeTheHomeVideo Thank you sir :p

[@JGoodwin]

What I heard: CXL = Tacos + Limes + soda. Key features: juicing, slicing, sharing Easier for my brain: CXL = a shared high speed memory bus. Key features: less copying, more flexibility (aka pooling) Do I understand correctly that it essentially context switches with the PCIe bus?

[@JustBiTurbo]

Is this similar to the current apple silicone implementation?

[@ServeTheHomeVideo]

Apple does not have to deal with this with the M1. This is mostly a technology for much larger systems.

[@jpconstantineau]

After watching this, I feel like fish tacos...

[@seylaw]

I'd like to see the Gen-Z connector sooner or later making it to the market. While compatibility with older gear is great, it comes at a cost.

[@GGBeyond]

So if I'm understanding this correctly, I can eat my servers next year?

[@OVERKILL_PINBALL]

So you don't put the lime in the coconut anymore? :P

[@berndeckenfels]

Nobody will give me my time wasted watching this back. But now I want a Limed Taco

[@Entity8473]

My local limes are way too acid to call delicious but great for the cold and flu.

[@jms019]

What about oranges and grapefruit ? I like those too

[@ServeTheHomeVideo]

I have never done grapefruit on tacos and in "soda"

[@2xKTfc]

Memory shared across devices - so basically AGP all over :D

[@creker1]

No, AGP is simple DMA. CXL adds complete solution for cache-coherent access with complex protocols for various use cases. It's akin to buses we have between processors where they exchange data to keep their caches in sync.

[@agisten]

AGP was ahead of it's time, the issue was necessary bus and memory speeds did not exist or were too expensive

[@Ian_Carolan]

OK, so dynamic resource sharing?

[@computersales]

I didn't care for the comparison since it just left me confused. Is that basically a new memory allocation/utilization standard through PCIe 5? Also there are easier ways to get tacos as a tax deduction ;)

[@markhahn0]

Yes. the main point of CXL is coherent memory access.

[@Cynyr]

All this talk of composable computers with shelves of memory and compute and such is starting to sound a lot like a main frame of old. Though in many ways "the cloud" is pretty much that right now, with some overheads.

[@Mack_Dingo]

So its last Q of '24 did CXL make it big?

[@ServeTheHomeVideo]

CXL 2.0 CPUs are being released over the next 2 months. It has a lot of support, and if you saw our Meta MAIA piece from Hot Chips, it looks like they have the system ready for CXL 2.0 devices (CXL 1.x does not really work in the system topology they showed.)

[@Gjarllarhorn1]

now I want tacos! Love the analogy!

[@ServeTheHomeVideo]

I pretty much always want tacos.

[@Gjarllarhorn1]

@@ServeTheHomeVideo out of curiosity, do you think with technologies such as CXL we'll come closer to a "true" cluster where you have a pool of resources and you add just what you need? i.e. compute nodes, memory nodes, storage nodes

[@darkpowerxo]

Where can I buy the Samsung cxl 512gb ?

[@MurchyMurch]

What is it Tuesday or something??

[@ServeTheHomeVideo]

It was when I recorded this :-)

[@NateTheBrewer]

Someone’s making daiquiris later.

[@bw_merlin]

So CXL will only used for sharing memory? For things like composable infrastructure which uses PCIe, will PCIe continue to be used or will CXL replace PCIe for this?

[@creker1]

CXL is PCIe. It's an extension based on the same protocol and physical layer. CXL is not meant for composable infrastructure. CXL only works inside a server. For composable infrastructure you need different technologies like Gen-Z.

[@hikaru-live]

Come to think of it, if CXL is good enough, AMD might just put CXL/PCIe combo units on their CPU CCX dies, making CXL-enabled Ryzen chips entirely IO die free.