Ask HN: What are the little freezes while typing normally on a laptop?

[themodelplumber]

This is an issue I'm having on a Latitude 7490 i7-8650U, 64GB RAM, SSD, currently running Manjaro...

While typing into Chrome every once in a while (ctrl-l, type search term) the input freezes for a couple seconds, like in the middle of typing the word Germany, it's like G-e-r (freeze) m-a-n-y

This seems off for "system capability" reasons, because A) none of my other laptops do this, even the old Lenovo T420 doesn't do this and B) I guess all it's doing is looking through my Chrome history.

The pauses also happen at other times when using different typing tasks in other apps. But I haven't found a good way to replicate this so far.

I made a 70GB swap file on the off chance that it had something to do with it, but the pauses still happen.

What might be some good places to start in troubleshooting? Is there some system caching mechanism or something else I should look into?

I'd be interested if this leads to more understanding of what's going on behind the scenes, so thought I'd ask here. Thanks.

[ofalkaed]

How is your touchpad setup? Depending on its settings it could be getting confused when you palm brushes it during typing, it pauses keyboard entry while it waits for your to to see what you are doing with the cursor. Probably set with synclient but I have not used Manjaro since it was brand new so I don't know. Lockeddrag/timeout, palmdetect, singletaptimeout and probably a few other settings could cause this, simple test is just to disable the touchpad and see if it keeps happening. If you only notice it while typing this is a good bet.

Edit: No, singletaptimeout could not cause this, was not thinking straight.

[themodelplumber → ofalkaed]

Ah, that's interesting too, I'll look into the possibility it's the touchpad.

[PaulHoule]

I don’t know if it your problem but those Dell power bricks sometimes fail to communicate how much power they supply which can cause a machine to feather the CPU and act sluggish. I’ve had many bricks (at least 4) go bad and I think some of the counterfeit Dell bricks last longer than real Dell bricks.

Check your CPU frequency.

[themodelplumber → PaulHoule]

That's interesting, I ran `cpupower frequency-info` a bunch of times and it reports a range from 900 MHz to 2.1 GHz, with the brick plugged in. It says the processor supports a range of 400 MHz to 4.8 GHz.

How can I check to see if this is a power brick problem?

[ofalkaed → themodelplumber]

Use the userspace governor and set the speed too something like 2ghz and see if the problem happens, read the manpage for cpufreq-set if you need help.

Edit: you would probably be fine just setting the governor to performance and doing so would be a good thing to do as well as the userspace governor, if you have issues on performance but not userspace that means there is something up when it switches speeds, kernel/driver issue most likely. Maybe microcode?

[themodelplumber → ofalkaed]

Is there a recommended userspace governor?

[ofalkaed → themodelplumber]

There is only one, it allows you to set an explicit frequency from userspace. The cpufreq-set man will answer all your questions. Not all CPUs support userspace, cpufreq-info will list the available governors.

[themodelplumber → ofalkaed]

OK, thanks, I see it has quite a few options.

Edit: I installed and enabled laptop-mode-tools (per Manjaro Wiki) and I see the average frequency is now in the 2-4 GHz range, still on AC power. So maybe this changes things, will see.

Edit 2: Also installed thermald and started the service in case it's needed. But of course baloo just started indexing, so I'm not sure if my CPU freq is now higher by default or if it's just temporary...

[ofalkaed → themodelplumber]

Another thing which comes to mind, you can try enabling or disabling p-states, intel_pstate=enable/disable in the kernel parameters for grub. If memory serves if cpu-freqinfo gives you a list of governors that means pstates are disabled, if they are enabled you will just get two governors at most. P-states work well with some configurations and cause issues with others. Been awhile since I have had to deal with this but I have one laptop that did have issues with p-states enabled, things would run hot and I would get glitches and laptop would just crash under very heavy loads, disabling p-states solved it. My other laptop would never get to speed and was very sluggish unless p-states was enabled.

I have not had to deal with this sort of thing since I gave up rolling release distro so I do not remember the exact details.