I'd like to see clearly explained Linux boot code that does not invoke a prayer to Satan.
Reworking 30 lines of Linux code could cut power use by up to 30 percent
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Re: Reworking 30 lines of Linux code could cut power use by up to 30 percent
#92The flip side of this is meta having a hack that keeps their GPUs busy so that the power draw is more stable during llm training (eg don't want a huge power drop when synchronizing batches)
Have a link to an article talking about them doing this?
I tried desperately to source this even before seeing your request.
My current guess is that I heard it on a podcast (either a Dwarkesh interview or an episode of something else - maybe transistor radio? - featuring Dylan Patel).
I'll try to re listen to top candidates in the next two weeks (a little behind on current episodes because I'm near the end of an audiobook) and will try to ping back if I find it.
If too long has elapsed, update your profile so I can find out how to message you!
Re: Reworking 30 lines of Linux code could cut power use by up to 30 percent
#93The flip side of this is meta having a hack that keeps their GPUs busy so that the power draw is more stable during llm training (eg don't want a huge power drop when synchronizing batches)
I thought of this too. Iirc it was bigger problem because surging spikes in power and cooling were harder and more costly to account for. I'm not au fait with network data centres though, how similar are they in terms of their demands?
I think the issue is exactly the spikiness because of how AC electricity works (whereas if the data centered were DC - eg wired through a battery - it wouldn't be an issue)
I expect you're right that GPU data centers are a particularly extreme example
Re: Reworking 30 lines of Linux code could cut power use by up to 30 percent
#94Key paragraph: "This energy savings comes with a caveat. “It is sort of a best case because the 30 percent applies to the network stack or communication part of it,” Karsten explains. “If an application primarily does that, then it will see 30 percent improvement. If the application does a lot of other things and only occasionally uses the network, then the 30 percent will shrink to a smaller value.”"
I'd suggest a submission title change to "...cut networking software power use..."
Not so sexy. But as a force multiplier that's still a lot of carbon probably.
Re: Reworking 30 lines of Linux code could cut power use by up to 30 percent
#95Earlier quoted context omitted.
Year ago, I posted here that there should be some sort of ongoing Green X-Prize for this style of Linux kernel optimization. It's still crazy to me that this doesn't exist.
I would hope that the hyperscalers have sufficient economic incentive to optimize this without an X-prize.
It's a public good where the biz that creates it captures very little of the value it generates, so investment in this kind of optimization is likely far below optimal.
Re: Reworking 30 lines of Linux code could cut power use by up to 30 percent
#96Earlier quoted context omitted.
I was curious how much this would be applicable to home routers. I confess I'm dubious on major savings for most home users, though? At least, at an absolute level. 30% of less than five percent is still not that big of a deal. No reason not to do it, but don't expect to really see the results there.
Practically none of it would be applicable (if using a commercial router). They all use hardware offloading, and traffic seldom touches the CPU. Only "logical" tasks are raised to the CPU, like ARP resolution and the likes (what’s called "trap to cpu"). If you’re doing custom routing with a NUC or a basic Linux box, however, this would gain massive power savings because that box pretty much only does networking.
if you run a VPN server, i assume all the traffic will come to CPU to decrypt, right?
Re: Reworking 30 lines of Linux code could cut power use by up to 30 percent
#97Linux added a busy polling feature for high performance networking. Most Linux software does not use it, but software used in datacenters (e.g. by CDNs) that does use it makes the system very energy inefficient when things are not busy. This patch gives the the kernel the ability to turn that off when not busy to regain energy efficiency until things become busy again. The article name is somewhat misleading, since i…
> The article name is somewhat misleading, since it makes it sound like this would also apply to desktop workloads.
The article name is, Data Centers Can Slash Power Needs With One Coding Tweak: Reworking 30 lines of Linux code could cut power use by up to 30 percent
The article says, “It is sort of a best case because the 30 percent applies to the network stack or communication part of it,” Karsten explains. “If an application primarily does that, then it will see 30 percent improvement. If the application does a lot of other things and only occasionally uses the network, then the 30 percent will shrink to a smaller value.”
It seems you only read the HN title? If so, why bother to critique the article's title?
Re: Reworking 30 lines of Linux code could cut power use by up to 30 percent
#98Linux added a busy polling feature for high performance networking. Most Linux software does not use it, but software used in datacenters (e.g. by CDNs) that does use it makes the system very energy inefficient when things are not busy. This patch gives the the kernel the ability to turn that off when not busy to regain energy efficiency until things become busy again. The article name is somewhat misleading, since i…
But linux use outside datacenters and server farms is irrelevant in terms of power use anyways I don't think anybody would be confused in the context of power usage.
Re: Reworking 30 lines of Linux code could cut power use by up to 30 percent
#99Linux added a busy polling feature for high performance networking. Most Linux software does not use it, but software used in datacenters (e.g. by CDNs) that does use it makes the system very energy inefficient when things are not busy. This patch gives the the kernel the ability to turn that off when not busy to regain energy efficiency until things become busy again. The article name is somewhat misleading, since i…
It’s a lot more nuanced than that. Being in a data center doesn’t imply heavy network utilization. The caveat is clearly outlined in the article being workload based not deployment based. If you have a home machine doing network routing it would absolutely benefit from this. In fact I would say probably the vast majority of Linux installs are home network devices, just people don’t know it. Embedded Linux machines do…
> I would say probably the vast majority of Linux installs are home network devices
I'm expect there are many, but the vast majority are likely massive datacenters with hundreds of thousands of machines each running multiple instances, and also Android phones are probably more common than home equipment. Edit: Also IoT, as someone else points out.
Re: Reworking 30 lines of Linux code could cut power use by up to 30 percent
#100Earlier quoted context omitted.
you don’t have to say “in datacenters” when talking about linux, that is the obvious context in the vast majority of cases
I'm reading this on an Android phone. The phone OS that has over 70% market share.
Linux is a tiny tiny part of the OS on phones. Power usage is most certainly not handled by android or linux in the vast majority of cases.
Who in their right mind would leave something so critical to the success of their product to a general purpose OS designed for mainframes and slightly redesigned for PCs?