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Intel’s Plans for 3DXP DIMMs Emerge

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Re: Intel’s Plans for 3DXP DIMMs Emerge

#31

Post by dragontamer »

glangdale wrote: post #23
jzelinskie wrote: post #20

It seems obvious in retrospect, but persistent memory adds a pretty exciting new advantage for persistent data structures. Another thought: As potentially paradigm changing technology like this becomes available will it ever make sense to redesign the OS?

Seriously, yes. If there was ever a time to rethink OS design, surely this is it. That being said, operating systems like Linux tend to capture most of the value from these kind of advances - often by dint of being able to simply 'get out of the way' if a sufficiently important user space process wants access to the device. But one would suspect that things have changed sufficiently from the 1970s to warrant a ground…

> Seriously, yes. If there was ever a time to rethink OS design, surely this is it.

Why?

Traditional servers are persistent: they never turn off. 500+ days of uptime is typical. And today, with VMs which at worst... hibernate... it seems like "never turning off" might be the norm.

Re: Intel’s Plans for 3DXP DIMMs Emerge

#32

Post by gravypod »

jzelinskie wrote: post #20

It seems obvious in retrospect, but persistent memory adds a pretty exciting new advantage for persistent data structures. Another thought: As potentially paradigm changing technology like this becomes available will it ever make sense to redesign the OS?

Zero serialization. Imagine installing a program and always having it "running". It may be swapped out but littetally everything in it is ready to go when you switch to it's window.

Re: Intel’s Plans for 3DXP DIMMs Emerge

#33

Post by inamberclad »

On a few occasions I've found myself in the presence of a senior engineer at a large defense company who would never stop talking about how persistent memory will change everything forever. Fair enough, but he'd go on about it in the weirdest ways. I think his impression is that the CPU registers would also be nonvolatile. I'm concerned that guy might be a few electrons short of a full orbital.

Re: Intel’s Plans for 3DXP DIMMs Emerge

#34

Post by vbezhenar »

inamberclad wrote: post #33

On a few occasions I've found myself in the presence of a senior engineer at a large defense company who would never stop talking about how persistent memory will change everything forever. Fair enough, but he'd go on about it in the weirdest ways. I think his impression is that the CPU registers would also be nonvolatile. I'm concerned that guy might be a few electrons short of a full orbital.

Saving and restoring CPU registers and flushing caches into non-volatile memory doesn't require much time or energy.

Re: Intel’s Plans for 3DXP DIMMs Emerge

#35

Post by vbezhenar »

gravypod wrote: post #32
jzelinskie wrote: post #20

It seems obvious in retrospect, but persistent memory adds a pretty exciting new advantage for persistent data structures. Another thought: As potentially paradigm changing technology like this becomes available will it ever make sense to redesign the OS?

Zero serialization. Imagine installing a program and always having it "running". It may be swapped out but littetally everything in it is ready to go when you switch to it's window.

Leaking memory would be dangerous.

Re: Intel’s Plans for 3DXP DIMMs Emerge

#36

Post by monocasa »

vbezhenar wrote: post #34
inamberclad wrote: post #33

On a few occasions I've found myself in the presence of a senior engineer at a large defense company who would never stop talking about how persistent memory will change everything forever. Fair enough, but he'd go on about it in the weirdest ways. I think his impression is that the CPU registers would also be nonvolatile. I'm concerned that guy might be a few electrons short of a full orbital.

Saving and restoring CPU registers and flushing caches into non-volatile memory doesn't require much time or energy.

Specifically, you can normally do something like that between when you notice the power dropping and when it drains too much and you have to shut down.

Re: Intel’s Plans for 3DXP DIMMs Emerge

#37

Post by freeone3000 »

mozumder wrote: post #26
jzelinskie wrote: post #20

It seems obvious in retrospect, but persistent memory adds a pretty exciting new advantage for persistent data structures. Another thought: As potentially paradigm changing technology like this becomes available will it ever make sense to redesign the OS?

Probably the optimal use of this technology is databases, since they rely most on random access to large persistent data. Any operating system that's designed around this technology is probably going to look like a database. Basically, boot to Postgres and all "files" are now SQL tables, stored in NVDIMM. Indexes are in DRAM, and critical nodes are in cache. All data (system and user) is organized and opinionated: Al…

Hey, that sounds line a mainframe... I wonder what it'll take to get zOS running on commodity.

Re: Intel’s Plans for 3DXP DIMMs Emerge

#38

Post by stouset »

dragontamer wrote: post #31
glangdale wrote: post #23

Earlier quoted context omitted.

Seriously, yes. If there was ever a time to rethink OS design, surely this is it. That being said, operating systems like Linux tend to capture most of the value from these kind of advances - often by dint of being able to simply 'get out of the way' if a sufficiently important user space process wants access to the device. But one would suspect that things have changed sufficiently from the 1970s to warrant a ground…

> Seriously, yes. If there was ever a time to rethink OS design, surely this is it. Why? Traditional servers are persistent: they never turn off. 500+ days of uptime is typical. And today, with VMs which at worst... hibernate... it seems like "never turning off" might be the norm.

On the contrary, as a security professional I’d be thrilled if servers had a lifespan of hours instead of weeks or months. Reimaging VMs/containers/machines from scratch frequently gives so many advantages.

When OS, system, or library updates happen, you can easily launch replacement servers on the updated stack, put them in the rotation, and decommission the old ones. This is so much simpler than trying to run OS upgrades in-place across an entire fleet. The longer a machine has been running between reboots, the lower my belief in its odds of upgrading and restarting cleanly.

Further, this regularly tests your load balancing setup and pretty much fundamentally gives you capacity to scale up and down as load permits. Problems will be discovered early on, instead of during crunch time when you have to scale or when a few of your machines go offline during peak hours.

Security-wise, you don’t just get the benefit of fast, regular updates. But you also get assurances that users haven’t left stale data like unencrypted database exports, PII dumps, etc. lying around. Go on a long-lived machine some day and check out users’ home directories. That shit is a gold mine if someone who wants to do harm gets on your systems.

Not to mention regular reimaging makes it harder for an attacker to establish a permanent foothold in your infra.

None of this has anything to do with fast persistent storage, but I sincerely hope the era of 500-day uptimes is waning.

Re: Intel’s Plans for 3DXP DIMMs Emerge

#39

Post by zeusk »

inamberclad wrote: post #33

On a few occasions I've found myself in the presence of a senior engineer at a large defense company who would never stop talking about how persistent memory will change everything forever. Fair enough, but he'd go on about it in the weirdest ways. I think his impression is that the CPU registers would also be nonvolatile. I'm concerned that guy might be a few electrons short of a full orbital.

Shouldn't be hard, all they have to do is a light context switch to idle thread on power loss interrupt and make the idle thread externally re-entrable.

Re: Intel’s Plans for 3DXP DIMMs Emerge

#40

Post by mycall »

stouset wrote: post #38
dragontamer wrote: post #31

Earlier quoted context omitted.

> Seriously, yes. If there was ever a time to rethink OS design, surely this is it. Why? Traditional servers are persistent: they never turn off. 500+ days of uptime is typical. And today, with VMs which at worst... hibernate... it seems like "never turning off" might be the norm.

On the contrary, as a security professional I’d be thrilled if servers had a lifespan of hours instead of weeks or months. Reimaging VMs/containers/machines from scratch frequently gives so many advantages. When OS, system, or library updates happen, you can easily launch replacement servers on the updated stack, put them in the rotation, and decommission the old ones. This is so much simpler than trying to run OS up…

You forgot, frequent rebuilds kill off any intrusion as the world reflashes -- unless they get into IoT or microcontroller packages.
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