Live data from Hacker News

An Unbelievable Demo

brendangregg.com

211–220 of 478 posts

Re: An Unbelievable Demo

#211
post #6

Can someone elaborate on why he takes a weird detour in the middle of the post to discourage forks? Is there some particular issue with supporting bpf tooling forks? As someone who has spent a lot of time in open source, forks are not a problem, they are indicative of a problem. Don’t cry when people fork and go a different direction, try to figure out why and see if you’re willing to change the project to accommodat…

Yes, there can be good reasons to fork (especially after making a fair effort to have things fixed), and bad reasons. But also yes: There are two particular issues with bpf tooling forks. 1) They look deceptively simple, but those that are kprobes-based are really kernel-specific and brittle, and need ongoing maintenance to match the latest changes in the kernel. One ftrace(/kprobe) tool I wrote has already been port…

> They look deceptively simple, but those that are kprobes-based are really kernel-specific and brittle, and need ongoing maintenance to match the latest changes in the kernel

It seems like there is a missing formal interface here if this is so brittle, no? If it’s hitting a bunch of internal kernel stuff shouldn’t this stuff just live with the kernel itself?

Re: An Unbelievable Demo

#212
post #67

Earlier quoted context omitted.

Why? If someone wants more control their interests already aren’t aligned with the community. Developer resources aren’t just some faucet easily redirected. It’s worse to have people trying to jam shit into the main project if they don’t actually care about the main project. That’s how you get contributions that are huge hacks and require more work to review and iterate on than is worth it to the community. If some c…

> That’s how you get contributions that are huge hacks and require more work to review and iterate on than is worth it to the community. And yet the author here is saying please work together. Presumably he or the community is okay with picking apart those huge hacks. I'm not sure why you should care what that community is willing to accept, unless you're part of it. > If some company forks for an observability produ…

> If I had to paraphrase the part of the post you're critiquing, I would do so as "If you're using these tools, don't feel like you have keep any stuff you do separate. We'd like to build something better for everyone, so feel free to contribute to the project rather than keeping it separate and we can all build on each other's work." That's pretty standard open source ideals IMO.

Sure, that’s just a completely different writing of what’s actually there. The original post is an instruction not to do something. Your interpretation is a much more open “pull requests accepted”.

His reply clarifies that he doesn’t want broken shit out there so your reading is incorrect. He does want to discourage forks because they are subtle to get correct and doesn’t want shit out their sullying bpf’s reputation.

Re: An Unbelievable Demo

#213
post #202

Is the "D" prefix in things like DTrace a Sun standard/convention? What does it mean, for example in the JVM arguments start with "D" as well. Any history to this?

TL;DR: DTrace uses a minimalistic C dialect called D to write it's probes, hence the name. In order to trace arbitrary code, it has to inject these into the code site that you want inspected. If you could just inject arbitrary C, you'd get the issue of potentially adding probes which change the behaviour of your code under test to a degree where new bugs/behaviours are introduced or old bugs/behaviours are masked. DT…

>DTrace uses a minimalistic C dialect called D

Which is completely unrelated to the other language called D, also known as DLang. (which was released 4 years earlier than DTrace by the way)

Re: An Unbelievable Demo

#214
post #196

My stories are very minor. I did my PhD in a reasonably well regarded mechanical engineering lab. My area is experimental fluid mechanics. I ended up writing a lot of Matlab code while there and even worked with a spin out company from the lab in the biotech sector for a while. I'd get a lot of other students coming to me for coding help. Most just wanted me to do their job for them and I was too naive to say no. One…

> I'd get a lot of other students coming to me for coding help. Most just wanted me to do their job for them and I was too naive to say no. One wanted to count cells in a microfluidic device using image processing. I sat down with them for a couple of hours and walked them through a few methods they could look into to get started collecting all the examples in a script. Basic stuff so they wouldn't feel overwhelmed. A few months later I see he published my simple introduction as a paper with zero modifications. He had the good grace to at least thank me in the acknowledgments.

That can't be the whole story, surely? You verbally suggested a couple of possibilities for what might work and wrote down a couple of lines of code, and then I imagine the student tried out all of those possibilities and reported what did and didn't work? I mean, what academic journal would want to publish half-working examples with unstudied properties?

Mind you, I agree about your broader point that (especially in academia) a lot of people don't really understand and respect code authorship.

Re: An Unbelievable Demo

#215

Earlier quoted context omitted.

The article says the story was from 2005. Open source was very much widely known at that time. Linux was 13 years old by then, and Sun themselves open sourced both DTrace and Solaris that same year.

Widely known... by a few techies. Well, certainly many more than in 1995, right? But can't compare those times to these days.

More than a few "techies", around here at that point software licenses were already part of the mandatory undergraduate "computer literacy" course...

Re: An Unbelievable Demo

#216

Earlier quoted context omitted.

I was in shock, and a bit furious at being ripped off, but didn't feel there was a lot I could do about it. I edited this bit out (I was trimming the post): "You might wonder why I didn't talk about this first case publicly at the time. I'd already informed them of the problem privately and how to fix it, so there wasn't more to say. Also, Sun was the number one employer in town, and to be publicly critical could be…

Sun was the number one employer in town in Australia? What?!

[deleted]

Re: An Unbelievable Demo

#217
post #60

Earlier quoted context omitted.

But there are consequences; Belarus is now cut off from air travel except with Russia. Flights are avoiding their airspace. They are a pariah.

Have you seen the coverage of the interview of Roman Protasevich? The visible injuries on his wrist and his recently adjusted attitude are alarming. https://www.bbc.com/news/world-europe-57353413

That's why it's so disappointing that the plane ended up diverting.

For Roman there is no way back after that. It's an atrocity, but ultimately Belarus authorities are responsible for those and the torturing.

Europe needs to ensure its planes are not hijacked mid-air like this in the future, to protect all of us and foremost journalists and activists.

Re: An Unbelievable Demo

#218

Earlier quoted context omitted.

Sun was the number one employer in town in Australia? What?!

Sorry, should have said "tech" employer, and this is referring to Sun and its ecosystem. A few years earlier I gave a talk to a local University about the job market and asked the comp sci students to have a showing of hands as to whether they thought they'd work on Windows or Solaris when they graduated. Most hands went for Windows. Then I showed the local job statistics: Sun Solaris was number one.

I come from Melbourne and know that there are several rather large multimational engineering centers in Melbourne around this time period. Ericsson, NEC and Robert Bosch comes to my mine..

Perhaps largest in Sydney...Great article btw!

Re: An Unbelievable Demo

#219

Earlier quoted context omitted.

Serious question, how does that hurt the original project? This has never been a concern in the projects I’ve worked on. Getting mad every time some developer writes code that didn’t go to your project is a good way to be mad all of the time.

Just a couple of example scenarios: - Someone sells you BPF observability that's buggy and dissapointing, and you avoid BPF in the future. So in that case it's hurt the BPF community. - Funding goes to a project that gives nothing back, instead of funding a project that does. Again, it hurts the community as funding isn't infinite.

> Someone sells you BPF observability that's buggy and dissapointing, and you avoid BPF in the future. So in that case it's hurt the BPF community.

Ok, so someone sells me closed source tooling that uses BPF and it’s buggy and disappointing, so I avoid BPF in the future. This association problem exists regardless of closed source vs a fork vs an old release.

> Funding goes to a project that gives nothing back, instead of funding a project that does. Again, it hurts the community as funding isn't infinite.

This only hurts if it’s a closed/hidden fork. This also presumes that the fork isn’t just stripping out tons of upstream features (I’ve had to do this for clients because “security”).

My view is that forks of open source (GPL in particular) should be encouraged and done in public. Iterating on central projects only is just so slow and stifling.

Maybe your projects have very little churn so lots of people experimenting in parallel doesn’t make sense, but this has been my experience with larger infrastructure projects. Let a thousand flowers bloom.

Re: An Unbelievable Demo

#220
post #203

Earlier quoted context omitted.

If that's what you took from the article, then you got completely the wrong end of the stick. The problem was the removal of the author's attribution and illegal relicensing. He says himself he was glad when Apple later included his tools in macOS with correct attribution and licensing.

Exactly. That was the problem that he saw. The problem he should have noticed was that the Sun was selling the code he wrote for hundreds of thousands of dollars and not passing any of that on to him. Step one shouldn't have been to worry about putting his header comment back in place and getting them the latest version of his code to sell to their customers. It should have been negotiating a redistribution license f…

No, the problem was the licensing change and removal of attribution. I would strongly suggest reading what Brendan says in the article.

On this topic, I work for Red Hat where we made $3.4 billion in revenues in the last published year (before being acquired), making exclusively open source software which you can download yourself for no cost.

Post reply on HN