←back to thread

A friendly tour of process memory on Linux

(www.0xkato.xyz)
226 points 0xkato | 7 comments | 03 Nov 25 23:04 UTC | HN request time: 1.427s | source | bottom
Show context
drbig ◴[03 Nov 25 23:43 UTC] No.45805856[source]▶
Instruction pipelining and this is exactly why I wish we still have the time to go back to "it is exactly as it is", think the 6502 or any architecture that does not pretend/map/table/proxy/ringaway anything.

That, but a hell lot of it with fast interconnect!

... one can always dream.

replies(4): >>45806429 #>>45806633 #>>45806856 #>>45809893 #
taeric ◴[04 Nov 25 01:03 UTC] No.45806429[source]▶
I'm curious how this dream is superior to where we are? Yes, things are more complex. But it isn't like this complexity didn't buy us anything. Quite the contrary.
replies(1): >>45806570 #
harry8 ◴[04 Nov 25 01:30 UTC] No.45806570[source]▶
> ...buy us anything.

Totally depends on who "us" and isn't. What problem is being solved etc. In the aggregate clearly the trade off has been beneficial to the most people. If what you want to do got traded, well you can still dream.

replies(1): >>45811661 #
1. taeric ◴[04 Nov 25 14:52 UTC] No.45811661[source]▶
Right, but that was kind of my question? What is better about not having a lot of these things?

That is, phrasing it as a dream makes it sound like you imagine it would be better somehow. What would be better?

replies(1): >>45814134 #
2. layer8 ◴[04 Nov 25 18:17 UTC] No.45814134[source]▶
Things would be simpler, more predictable and tractable.

For example, real-time guarantees (hard time constraints on how long a particular type of event will take to process) would be easier to provide.

replies(1): >>45814454 #
3. taeric ◴[04 Nov 25 18:42 UTC] No.45814454[source]▶
But why do we think that? The complexity would almost certainly still exist. Would just now be up a layer. With no guarantees that you could hit the same performance characteristics that we are able to hit today.

Put another way, if that would truly be a better place, what is stopping people from building it today?

replies(1): >>45814562 #
4. layer8 ◴[04 Nov 25 18:51 UTC] No.45814562{3}[source]▶
Performance wouldn’t be the same, and that’s why nobody is manufacturing it. The industry prefers living with higher complexity when it yields better performance. That doesn’t mean that some people like in this thread wouldn’t prefer if things were more simple, even at the price of significantly lower performance.

> The complexity would almost certainly still exist.

That doesn’t follow. A lot of the complexity is purely to achieve the performance we have.

replies(1): >>45814628 #
5. taeric ◴[04 Nov 25 18:58 UTC] No.45814628{4}[source]▶
I'm used to people arguing for simpler setups because the belief is that they could make them more performant. This was specifically the push for RISC back in the day, no?

To that end, I was assuming the idea would be that we think we could have faster systems if we didn't have this stuff. If that is not the assumption, I'm curious what the appeal is?

replies(1): >>45815032 #
6. layer8 ◴[04 Nov 25 19:36 UTC] No.45815032{5}[source]▶
That’s certainly not the assumption here. The appeal is, as I said, that the systems would be more predictable and tractable, instead of being a tarpit of complexity. It would be easier to reason about them, and about their runtime characteristics. Side-channel attacks wouldn’t be a thing, or at least not as much. Nowadays it’s rather difficult to reason about the runtime characteristics of code on modern CPUs, about what exactly will be going on behind the scenes. More often than not, you have to resort to testing how specific scenarios will behave, rather than being able to predict the general case.
replies(1): >>45815485 #
7. taeric ◴[04 Nov 25 20:23 UTC] No.45815485{6}[source]▶
I guess I don't know that I understand why you would dream of this, though? Just go out and program on some simpler systems? Retro computing makes the rounds a lot and is perfectly doable.