bmenrigh

A friend of mine got me on Gentoo in 2004. He spent all of his time tweaking compiler flags like -O3 -ffast-math -fomit-frame-pointer -funroll-loops and running into so many issues in the process. I think he only lasted about 9 months on Gentoo. To this day, he's the only person I've ever met that was there for performance.

I'm still on Gentoo 22 years later.

I doubt this oft-repeated stereotype was every particularly accurate. I'm not aware of any current Gentoo users on the distro specifically for performance reasons. Gentoo users are in it for control over their system and customization.

The “convex hull of ideas” is a very interesting framing.

My own suspicion/guess is that AI can break out of the bounds of the convex hull in math, and that’s going to become apparent soon.

At least 1/3rd of these predictions aren't clear enough to determine exactly what is being claimed/predicted. Even after reading the full comment multiple times, on a lot of them I couldn't tell where the author had set the goalposts well enough to say whether we've crossed it or not.

I’m doing all my CPU measurements with ‘perf stat’ on Linux.

Entirely in C. Compilers are pretty good these days. Almost every time I try to outsmart them I make things worse.

It’s a backtracking search program looking for integer solutions to a specific problem. I’ve tuned a series of bloom filters to fill my L2 cache so that I rarely have to touch main memory (this alone took my IPC from 0.1-0.3 to 3.0 per thread). Without SMT it’s 4.6 IPC/core.

I think it’s only able to exceed 4.0/thread with SMT off because of a uops cache? From what I’ve read the Zen5 front end only had a 4-wide instruction decode per thread.

I was recently able to get a workload of mine optimized enough on Zen 5 to hit a sustained 6.0 IPC/core (3.0 / thread) at 5.1 GHz. Seeing the a > 99.8% branch prediction rate and a > 99.99% L2 cache hit rate retiring > 1T instructions every 3 seconds feels amazing.

Zen5 is incredible when you're able to make the most of it. I’m super excited about Zen6.

For a long time (probably 2002-2010) I really wanted to do LFS. But I've been on Gentoo since 2004 which, over the last ~22 years, has probably exposed me to almost everything LFS would have, plus a lot more it wouldn't have. I still wish I'd did it way back when. I probably would stumbled through fewer issues had I.

This is why the checking doors / neighborhood analogy isn't a good one.

Having one person with poor computer security negatively impacts everyone. Hacked sites turn into phishing landing pages, exploit kit hosting, stolen data dumps, and launching off points for attacks on everyone else. The vuln scanning ShadowServer is doing is meant to be a public good, which is why they share the info with ISPs and governments.

Security is too intertwined to stand by and say other people's vulnerabilities aren't your problem.

If the neighborhood was constantly being canvased by criminals checking doorknobs, so your concerned neighbor went over to your house to check your doorknob, and then let you know if you accidentally left it open, would you also accuse your neighbor of being a criminal trying to break in?

Calling vuln scanning from a non-profit a felony is a bit of a stretch. Many for-profit companies do similar vuln scanning and then threaten companies with security "scorecards". That is borderline extortion.

I just checked my own webserver logs (I also run a sever in the ntp pool) and I too see some hits in my webserver logs.

They look to all be log4j vuln scanning activity (CVE-2021-44228), and the volume isn't that high (a few a day, and not every day). They just have some overzealous vuln scanning. And yes, they shouldn't have the NTP pool under their DNS name.

I've had all sorts of strange things happen because of my ntp pool membership, this one is pretty far on the benign end of things.

If someone wants to beat me to either a solution, or proving no solutions exists, then by all means :-)

I think it's an extraordinarily hard problem computationally, even with exceptional theoretical backing.

Where people may be able to beat me is if no solution exists-- there may be some highly nontrivial, but findable unsatisfiability argument.

Well I’m first exhausting some promising regions of the search space which should complete in less than 2 weeks. After that I strongly suspect a solution doesn’t exist (for the column grouped space I’m searching).

If it were just a matter of a few thousand dollars of computer time (say, less than $5000) the money would already be spent and I’d have an answer.

We’ll see, I may build the tooling to distribute the search and enlist help from others interested.

It’s only been about 2 weeks since I was able to drop the runtime from “age of the universe” levels to just decades.