I mean no harm.

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Joined 1 year ago
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Cake day: July 4th, 2023

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  • The https://ektoplazm.com/ is still up, though with archive mode and a rate-limit. Please clone it. One day I’ll start a process that I’ll not regret, while I/you can.

    I have a puny 30GiB slice of it, and it’s the best thing that I have. All for free. Non-pirated. (the owner has reported the total space consumed is multiple a 1TB)

    Btw, Infected is making a gig in my town. And I’m struck with disbelief of the absurdity of it. Here? no way. Bust a move will be my vain. If I could inhale it I would.



  • A dum question: if both candidates are unable to function, then what happens? (Trump for his crimes, Biden for getting dementia…)

    Meanwhile in Finland: the Finnish version of “build the wall”:

    Parliament’s Administrative Committee will not resume its discussion of the Refoulement Act until after the weekend. The committee is still so far behind schedule that it could not complete its work today. The debate on the bill continued during the committee meeting, which started at 5 p.m. but ended quickly. Peltokangas says there was no drama at the meeting. yle.fi

    The bill needs 5/6 parliamentary approval and politicians are already sweating over it because it touches too many international treaties + constitution. Debate is mostly: is it ready yet? is it ready yet? is it ready yet? (While the committees checking the bill are getting more uneasy by the bill’s content…)

    Also you got link text and url backwards.

    Oops, fixed.





  • I agree that UI should always take priority. I shouldn’t have to do anything to guarantee this.

    I have HZ_1000, tickless kernel with nohz_full set up. This all has a throughput/bandwidth cost (about 2%) in exchange for better responsiveness by default.

    But this is not enough, because the short burst UI tasks need near-zero wake-up latency… By the time the task scheduler has done its re-balancing the UI task is already sleeping/halted again, and this cycle repeats. So the nice/priorities don’t work very well for UI tasks. Only way a UI task can run immediately is if it can preempt something or if the system has a somewhat idle CPU to put it on.

    The kernel doesn’t know any better which tasks are like this. The on-going EEVDF, sched_ext scheduler projects attempt to improve the situation. (EEVDF should allow specifying the desired latency, while sched_ext will likely allow tuning the latency automatically)


  • No, I definitely want it to use as many resources it can get.

    taskset -c 0 nice -n+5 bash -c 'while :; do :; done' &
    taskset -c 0 nice -n+0 bash -c 'while :; do :; done'
    

    Observe the cpu usage of nice +5 job: it’s ~1/10 of the nice +0 job. End one of the tasks and the remaining jumps back to 100%.

    Nice’ing doesn’t limit the max allowed cpu bandwidth of a task; it only matters when there is contention for that bandwidth, like running two tasks on the same CPU thread. To me, this sounds exactly what you want: run at full tilt when there is no contention.


  • The kernel runs out of time to solve the NP-complete scheduling problem in time.

    More responsiveness requires more context-switching, which then subtracts from the available total CPU bandwidth. There is a point where the task scheduler and CPUs get so overloaded that a non-RT kernel can no longer guarantee timed events.

    So, web browsing is basically poison for the task scheduler under high load. Unless you reserve some CPU bandwidth (with cgroups, etc.) beforehand for the foreground task.

    Since SMT threads also aren’t real cores (about ~0.4 - 0.7 of an actual core), putting 16 tasks on a 16/8 machine is only going to slow down the execution of all other tasks on the shared cores. I usually leave one CPU thread for “housekeeping” if I need to do something else. If I don’t, some random task is going to be very pleased by not having to share a core. That “spare” CPU thread will be running literally everything else, so it may get saturated by the kernel tasks alone.

    nice +5 is more of a suggestion to “please run this task with a worse latency on a contended CPU.”.

    (I think I should benchmark make -j15 vs. make -j16 to see what the difference is)




  • JATth@lemmy.worldtoLemmy Shitpost@lemmy.worldrollin' coal
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    6 months ago

    Especially now that they’ve started releasing tritiated water into the ocean for the next 20-50 years or whatever the fuck the plan is supposed to be.

    the tritiated water is no-more concentrated than what other power plants around the world release. (the latter may be surprising to know) In addition, tritium has a half-life of only 12.3 years and is diluted in a literal sea, which is an extremely good radiation shield.


  • I put too way too much effort in this reply… Yes… it’s nerve racking, especially if you are resorting to BIOS flashback to boot the CPU on an older (new) board.

    Can’t get visuals (except maybe leds/indicators on the motherboard itself) when your CPU is incapable of accessing the ram or the devices yet. All external devices normally communicate through the RAM. (And by external, I mean not on the CPU package) Yet, the CPU has to solve out this chicken-and-egg problem of how to progress from the cold-boot without knowing what external RAM is installed. There are plethora of timing/clock-cycle/voltage settings for one stick of ram, which are tested on POST. Establishing sane DDR5/4 parameters is non-trivial. (I think it is order of +20!, twenty factorial: 2432902008176640000, if there were no starting point of XMP, JEDEC etc.)

    I use hand tuned settings for DDR4, and on cold boot, the BIOS adjust the settings which I didn’t forbid it to do. Unless I unplug the PSU from the wall, the BIOS won’t retrain the memory again. I suspect my settings still aren’t 100% stable. (over period of years) Non-cold-boot assumes the ram works 100% same on each power up. If some OC setting drifts past a threshold once the system is heat soaked or receives more EMI interference, this could provoke a crash/BSOD etc. in absurd theory having a busy wifi router next the ram could cause the bios to select more robust/conservative settings to counter the EMI interference. Would be fun to know, if this would be true.


  • NO.

    I watched YT channel that had rescue toucans and they belong to the wild. Every 5mins the owner reminds (and I believed he was/is a good owner) of this fact.

    Funniest thing was the velociraptor mode and pure chaos. Saddest thing was seeing them die to health complications, despite the good care.