Why Fast PCs Stutter (Interrupts Explained)

Learn about interrupts and how they can slow down even high-end computers.

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[mehzera]

I feel like the explanation on how to avoid it was cut out and replaced by the story of how it happened on a Mars rover in '97.

[Dexiray]

NGL was expecting a solution. Came out feeling like I went on Mars...

[SixManXV]

Priority inversion: when the ad prioritizes itself over the entire point of the video

[jotjakubjot]

4:34 Actually, debugging a rover on Mars isn’t the “most remote of remote debugging”—that title belongs to the Voyager spacecraft, which are nearly 20 billion kilometers away! Just recently, engineers had to fix a data issue on Voyager 1 by sending a command that took over 20 hours to travel one way. Imagine troubleshooting a computer by sending commands that take almost a day to arrive, and then waiting another day for feedback. In comparison, debugging on Mars is like fixing something across town, while Voyager is like trying to fix it from another planet entirely!

[jesus]

remember you can buy the best spec PC with the latest upgrades but you cannot upgrade your brain so it will bottleneck

[privacyvalued]

0:38 "If the processor accepts the request." Wait. CPUs can reject interrupts? [Does a bunch of research.] Well, I learned something new today. There are three types of interrupts: Maskable, non-maskable, and spurious. It's not so much as to whether the CPU rejects an interrupt so much as it can just choose to ignore it. Rejection implies a response. Firewalls, for example, can be configured to drop (no response) or reject (NACK response) packets. Spurious interrupts are the oddball. I'm not sure how those happen and couldn't find any examples.

[joshuaderosa]

the ad got into the way of how to avoid this.

[MayankJairaj]

One way i use to fix this while gaming:
1. Set all gaming related tasks to a high or very high priority (not realtime)
2. Remove CPU 0 from the CPU Affinity of these above tasks, aka all cores except CPU 0 should be ticked.
3. Disable dynamic tick for the gaming application (google how to)
4. Enable highest performance mode from windows and OEM settings
5. End Process Trees for heavy applications that arent being used.
6. Decrease priority of ur game distribution software (example steam to low) dont end it, u need it for playing the game.

[joshuaLLM]

That's great! I never really understood the whole interruption thing. Has anyone tried cleaning up Windows? They say it helps, but I'm not sure if it's a myth. By the way, does anyone know where I can get a license for Windows 10?

[BlueHasia]

I feel this really needs a part two. Never really heard of this, was not really explained well for me and steps to try to trouble shoot this issue left out

[HimitsuPOWER]

That was a great explanation, but where is the solution?!

[HerbaMachina]

Interrupt routines shouldn't cause your PC to stutter unless someome has implemented some really poor coding practices in that interrupt routine. Interrupt routines should execute in sub single milliseconds and shouldn't even be perceivable to you the user.

[theorphanobliterator]

thrashing doesn't have to go with interrupts, it's segmentation faults which occur due to multiple processes running at the same time. the phenomenon you're referring to is "interrupt storm", not to be confused with thrashing.

[NepuniLokhoInst]

I like your channel! I get educated on important topics related to computers and get a pinch of nostalgia everytime I watch it. All the best!

[microbuilder]

Jokes on you, my computer is so slow I cant tell the difference between an interrupt, hanging, or just regular operation lol

[KibbleWhite]

This brings back memories, one of the first thing learnt in my first job where the difference in interrupt timings with systems with and without a GUI.

[Bassquake]

Think you forgot the part about how to avoid it. I use LatencyMon to see what might be causing stutter. Often its drivers that needs updating (or downgrading) or some annoying windows process hogging the system.

[kourkoutas]

The Mars Pathfinder is an interesting one. Their software was actually capable for priority inheritance (this is when a task using a shared resource gets a priority bump while using that resource), which the solution to the priority inversion problem. The problem is that it was misconfigured to not use priority inheritance for that resource.

There's a bit of a terminology mix-up in the video between "criticality" and "priority". For real-time systems like what was running on the Pathfinder, this is an important distinction. Priority is a measure of "urgency" as in "this needs to happen first". Criticality is a measure of importance; this definitely needs to happen; often high criticality things can be of low priority when it comes to the schedule design of this type of system.

[marclevine]

I've been using computers for a long time. My 1st computer was a TI 99/4 I soon added an expansion box with a 32K memory expansion, Floppy disk controller, floppy disk drive and RS232 card (i'm 77). This was in the early 80's. When the system was writing to disk it would issue a system interupt. BTW, my 1st modem was a 300 baud where you would dial a number listen for a tone and then flip a switch.

[TheBzz]

Man, I thought my computer was just channeling its inner sloth, but it turns out it's just busy prioritizing its own existential crisis over actually doing what I tell it to do.