4 ms·

Fuck this guy gets on my nerves, acting like he's the only person in the world who knows what virtual memory is or that paging is some kind of dark magic only u

by smegel 14y ago

Fuck this guy gets on my nerves, acting like he's the only person in the world who knows what virtual memory is or that paging is some kind of dark magic only understood by kernel developers, rather than standard subject matter for any intro to computer architecture/OS concepts course.

PeterisP 14y ago
It did feel useful, as many new programs actually do manage much of their data exactly as he warns not to - keeping an in-memory cache of something they're (re)reading from disk.
peterhajas 14y ago
Whoa! Why the hostility? This article seems interesting, not arrogant.
- jspthrowaway2 14y ago
  You'll often see comments like OP on articles or comments from Kamp. I've left some. Poul-Henning Kamp is a polarizing figure. I sympathize with the sentiment on occasion, and I'm occasionally annoyed by his writing style ("everything but Varnish is written poorly" is evident in this one). Another one that bothered me was You're Doing it Wrong[1]; great information, offensive tone -- most of his publications in Queue are the same way. That said, I can also disregard most of that annoyance as he's a genuinely smart guy, and I want to know what he's trying to tell me. Put it this way: I'd listen to anything PHK has to say, but I'd (probably) never hire him because I need to foster a team environment, and PHK can be divisive when he communicates. I'm sure the commenters you see commit karma suicide like this feel the same way and are just quite poor at communicating what I have. OP dug in on a detail, but reading the rest of his comment another way, it's a criticism of the writing style and tone (in my reading). [1]: http://queue.acm.org/detail.cfm?id=1814327 http://queue.acm.org/detail.cfm?id=1814327
  - gruseom 14y ago
    I am impressed with how deftly you reframed (and redeemed) the GGP's bilious outburst. That was charitable of you, and makes me wish more people would do it.
cskau 14y ago
It might be a subject matter for most, but how many can honestly say they make use of, and eventually even remember, it after years of programming in high level programming languages on modern OSs?
gliese1337 14y ago
Consider: what proportion of programmers have taken an OS course? Specifically OSes, 'cause I know that virtual memory was not covered in any of the computer architecture courses I've taken. Now, how many of those programmers who know about virtual memory (larger than the number who have taken a course on operating systems, but still far from 100%, I'd wager) have actually realized "hey, virtual memory can make it so that I never have to explicitly write stuff to disk?" I certainly hadn't. Just because you expect people to know basic concepts, doesn't mean that an article explaining what they're useful for is useless. Quite the opposite, in fact.
- LnxPrgr3 14y ago
  My experience has been that most programmers are more or less clueless about how virtual memory works. At best, they understand it as letting you swap out memory to disk when memory runs low. Even ignoring Kamp's "mmap the world" approach, if I brought up any of his other ideas in a meeting with most programmers, there'd be immediate cries of premature optimization (and reinventing the wheel, in the case of using a single malloc'd chunk for workspaces). Never mind what we're talking about building or what we already know about the performance of different approaches, and never mind that a lot of important performance decisions are architectural and are a lot harder to change later on. These ideas just aren't on most programmers' radar—it's all evil voodoo to be avoided at all costs to them. How many programmers know the effect of a write from one CPU on the next read from another CPU on the same cache line? How many programmers know the relative cost of a syscall vs. a function call? How many programmers ever think about optimizing their use of CPU cache? Most of the time they get away with ignoring these things because they really don't matter in context. But sometimes they don't get away with it because these things do matter, and in those moments I wish more programmers had a better understanding of their machines and their operating systems.
deleted 14y ago
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by smegel 14y ago

PeterisP 14y ago

It did feel useful, as many new programs actually do manage much of their data exactly as he warns not to - keeping an in-memory cache of something they're (re)reading from disk.

peterhajas 14y ago

Whoa! Why the hostility? This article seems interesting, not arrogant.

jspthrowaway2 14y ago
You'll often see comments like OP on articles or comments from Kamp. I've left some. Poul-Henning Kamp is a polarizing figure. I sympathize with the sentiment on occasion, and I'm occasionally annoyed by his writing style ("everything but Varnish is written poorly" is evident in this one). Another one that bothered me was You're Doing it Wrong[1]; great information, offensive tone -- most of his publications in Queue are the same way. That said, I can also disregard most of that annoyance as he's a genuinely smart guy, and I want to know what he's trying to tell me. Put it this way: I'd listen to anything PHK has to say, but I'd (probably) never hire him because I need to foster a team environment, and PHK can be divisive when he communicates. I'm sure the commenters you see commit karma suicide like this feel the same way and are just quite poor at communicating what I have. OP dug in on a detail, but reading the rest of his comment another way, it's a criticism of the writing style and tone (in my reading). [1]: http://queue.acm.org/detail.cfm?id=1814327 http://queue.acm.org/detail.cfm?id=1814327
- gruseom 14y ago
  I am impressed with how deftly you reframed (and redeemed) the GGP's bilious outburst. That was charitable of you, and makes me wish more people would do it.

cskau 14y ago

It might be a subject matter for most, but how many can honestly say they make use of, and eventually even remember, it after years of programming in high level programming languages on modern OSs?

gliese1337 14y ago

Consider: what proportion of programmers have taken an OS course? Specifically OSes, 'cause I know that virtual memory was not covered in any of the computer architecture courses I've taken. Now, how many of those programmers who know about virtual memory (larger than the number who have taken a course on operating systems, but still far from 100%, I'd wager) have actually realized "hey, virtual memory can make it so that I never have to explicitly write stuff to disk?" I certainly hadn't. Just because you expect people to know basic concepts, doesn't mean that an article explaining what they're useful for is useless. Quite the opposite, in fact.

LnxPrgr3 14y ago
My experience has been that most programmers are more or less clueless about how virtual memory works. At best, they understand it as letting you swap out memory to disk when memory runs low. Even ignoring Kamp's "mmap the world" approach, if I brought up any of his other ideas in a meeting with most programmers, there'd be immediate cries of premature optimization (and reinventing the wheel, in the case of using a single malloc'd chunk for workspaces). Never mind what we're talking about building or what we already know about the performance of different approaches, and never mind that a lot of important performance decisions are architectural and are a lot harder to change later on. These ideas just aren't on most programmers' radar—it's all evil voodoo to be avoided at all costs to them. How many programmers know the effect of a write from one CPU on the next read from another CPU on the same cache line? How many programmers know the relative cost of a syscall vs. a function call? How many programmers ever think about optimizing their use of CPU cache? Most of the time they get away with ignoring these things because they really don't matter in context. But sometimes they don't get away with it because these things do matter, and in those moments I wish more programmers had a better understanding of their machines and their operating systems.

deleted 14y ago

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