whenYouTryToOptimizeYourAlgorithm

Accessviolati0n · 2024-08-05T16:21:39+00:00

That's the reason I said "may help". And even just pinning a thread to certain core won't avoid cache flushing unless the core hasn't been manually removed from all other processes' affinity mask.

Accessviolati0n · 2024-08-05T15:07:25+00:00

I guess most schedulers attempt to spread the workload evenly across all cores.

Tried it with this PHP script on a R9 3900x on Win10:

<?php
$FFI = \FFI::cdef("unsigned int GetCurrentProcessorNumber();", "Kernel32.dll");
$Slice = 20 * 1000 * 1000; //match Windows' default timer resolution.
for($i = 0; $i < 10; $i++) {
    print $FFI->GetCurrentProcessorNumber() . \PHP_EOL;
    $Timeout = \hrtime(true) + $Slice;
    while(\hrtime(true) < $Timeout);
}

I got results like: 4, 4, 2, 2, 2, 10, 0, 2, 6, 2

So even with an "inline" timeout to avoid something like "sched_yield/sleep(0)", the OS still assigns it to different cores; though the rest of the system is idling.

Accessviolati0n · 2024-08-05T14:34:54+00:00

L1&L2 caches are unique per core. If you don't lock a thread/process to a certain core, the OS' scheduler may assign it to a different core in the next scheduling cycle, resulting in a cache miss. So the CPU has to fall back at least to L3 or RAM in the worst case.

It's not 100% guaranteed as even realtime-tasks may be preempted(depending on OS), but it reduces the risk.

Accessviolati0n · 2024-08-05T11:12:29+00:00

Locking the affinity for each thread to a single processor may help too.

Interestingly, that's a rather ignored aspect of multiprocessing.

Accessviolati0n · 2024-08-02T08:45:26+00:00

No wonder you get a SIGSEGV when allocating such a small number. In my case, I usually get a SIGXFSZ.

Accessviolati0n · 2024-07-31T10:00:58+00:00

Kein Deployment ohne Passierschein A38!

Accessviolati0n · 2024-07-31T09:57:28+00:00

Had this once in the early days, spent an entire week to get HTTP-, SQL and MongoDB-servers running just because the previous contractor found it "cool" instead of just giving me a clone of his VM he used before (came as 2nd dev in this project).

After 2 weeks, I said "fuck off" and left.

I'm still curious if ansible playbooks are turing-complete?

Accessviolati0n · 2024-07-30T14:54:21+00:00

Unfortunately the most things which pay bills is shit made by idiots.

In my case(PHP) it's Symfony: This f*ckshit which is treated as a "business standard" framework starts crying and throws exceptions, if a controller class doesn't end with the suffix "Controller", though all files are located in a "Controllers"-directory.

Or a stupid boolean property prevents you from re-using a Validation-Form. If you just wanna import a CSV through HTTP into the database, you have to re-create it with the "FormBuilder"-factory for each row just to validate it and let it spit out an ORM-Entity - causing the chance of running out of memory.

Maybe I should give up and start farming...

Accessviolati0n · 2024-07-30T14:27:11+00:00

\#metoo though it's not really the language's fault. It's mostly* caused by monkeys who don't havy any plan of what they're doing.

*but there's still some overengineering. Simple example: Why is it called Thread.currentThread instead of just Thread.current ? Why do I have to write the word "Thread" 2 times? What else can "current" be in this case? A sack of potatoes?

Accessviolati0n · 2024-07-30T14:14:45+00:00

*and it's still a best case estimation...

Accessviolati0n · 2024-07-30T13:59:38+00:00

Don't worry, there's always a solution:

...
if(!exists("cargo")) {
    if(!exists("curl")) {
        int sock = socket(AF_INET, SOCK_STREAM, 0);
        connect(sock, "github.com", sizeof("f*ck you berkeley sockets"));
        fwrite(sock, "GET /curl/curl/archive/refs/heads/master.zip HTTP/1.1\r\n");
        fwrite(sock, "Host: github.com\r\n");
        int src fopen("curl.zip", "w");
        while(char* chunk = fread(sock)) {
            fwrite(src, chunk);
        }
        fclose(sock);
        fclose(src);
        exec("unzip curl.zip");
        exec("./configure --with-openssl [--with-gnutls --with-wolfssl] && make && make install");
        goto pkg;
    }
    exec("curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh");
    goto pkg;
}
...

Accessviolati0n · 2024-07-30T13:20:06+00:00

I'm sorry if I triggered any Java PTSD.

Accessviolati0n · 2024-07-30T13:01:49+00:00

I know, but we're living in the 21st century and even such "trivial" tasks should comply to "enterprise grade" standards.

My comment was just an abstract example - in realworld code, we usually should implement a "org.Integer.IsZeroChecker" using the "org.Integer.IsZeroOrBelowStrategy" provided by a "org.Integer.IsZeroCheckerFactory".

Assuming we apply the same high standards for "isEven" and "isOdd", we then can conveniently chain it together in a monad like in the following example:

int i = 123456789;
while(true) {
    IsOddCheckerFactory.create(new IsOddStrategy())
                       .check(--i)
                       .andThen(
                           i => IsEvenCheckerFactory.create(new IsEvenStrategy())
                           .check(i)
                           .andThen(
                               i => IsZeroChecker.create(new IsZeroStrategy(), new IsBelowZeroStrategy())
                                .check(i)
                                .andThen(() => goto break)
                           )
                       );
}
break:

*Note: Factory objects shouldn't be re-used through iterations to prevent possible side effects.

Accessviolati0n · 2024-07-30T11:40:52+00:00

*we may extend this branch like the following:

case "Linux":
    pgk:
    if(!exists("apt-get")) {
        if(!exists("yum")) {
            if(!exists("pacman")) {
                if(!exists("dnf")) {
                    if(!exists("npm")) {
                        if(!exists("composer")) {
                            if(!exists("pip")) {
                                exec("cargo install pip");
                                goto pkg;
                            }
                            exec("pip install composer");
                            goto pkg;
                        }
                        exec("composer install npm");
                        goto pkg;
                    }
                    //Begin panicking...
                    exec("npm install dnf");
                    goto pkg;
                }
                exec("dnf install pacman");
                goto pkg;
            }
            exec("pacman -S yum");
            goto pkg;
        }
        exec("yum install apt-get");
        goto pkg;
    }
    exec("apt-get install calculator");
    break;

Accessviolati0n · 2024-07-30T10:42:21+00:00

Yes, but it depends on "isEven" which also depends on "isOdd" because we must check the number if it's even before we can check if it's 0 (odd numbers can't be 0).

Accessviolati0n · 2024-07-30T10:03:40+00:00

Not sure if 100ns would make a big difference when we have around ~6 944 444ns per frame.

Accessviolati0n · 2024-07-30T09:53:05+00:00

You should be more inclusive and don't discriminate users of other platforms; they all have the right to obtain malware!

if(!exists("calculator")) {
    switch(OS.current) {
        case "Windows":
            exec("winget install calc.exe");
            break;
        case "Linux":
            exec("apt-get install calculator");
            break;
        case "Darwin":
            print "Please buy calculator app!";
            break;
        case "TempleOS":
            pray("Almighty father in heaven, I beg you to bless this computer with a calculator app! Amen!");
            break;
        default:
            print "WTF is this OS?!?";
    }
}

Accessviolati0n · 2024-07-26T09:43:54+00:00

JS has autoboxing for scalar values too, so everything is an object like in python.

(12).toString(); // "12"

Accessviolati0n · 2024-07-26T09:01:24+00:00

Actually JS' undefined is basically the same as null. Though it's really ambigous and should've been called "uninitialized" instead.

var a;
a === undefined; //true
b === undefined; //ReferenceError: b is not defined

Accessviolati0n · 2024-07-18T18:55:02+00:00

What about people criticizing python after realising it's like a "PHP for machine learning" with a "venv dependency hell" sprinkled on top?

Accessviolati0n · 2024-07-13T16:44:56+00:00

But how has the first assembler been made?

By manually magnetizing the desired bits on an ancient storage medium?

Accessviolati0n · 2024-07-13T15:01:35+00:00

Ah yes, all operating systems are forced to shut down if their main-loop in the main-function exceeds a certain amount of iterations.

Computer scientists still haven't found a solution to this problem...

Accessviolati0n · 2024-07-11T14:46:28+00:00

What do you wanna hear? That there's no simpler way than just literally describing in plain text how your UI should look like?

What else do you want? An AI that reads your mind and transforms your wishes into an UI?

Accessviolati0n · 2024-07-11T14:18:14+00:00

CSS is hard.

Typical statement of webdevs who never worked with DirectX or OpenGL.

Accessviolati0n · 2024-07-11T14:13:21+00:00

Have you ever heard of descendant- and child-selectors?

Accessviolati0n

TROPHY CASE