8 ms·

Try charging on the right and not on the left

204 points by spectaclepiece 5y ago

causi 5y ago
high CPU usage by kernel_task is caused by high Thunderbolt Left Proximity temperature, which is caused by charging and having normal peripherals plugged in at the same time. Did anyone ever figure out why exactly the temperature sensor was making kernel_task go crazy?
- mkl 5y ago
  The comment by jksoegaard may explain it: "the purpose of the thread is to force idleness". I guess it uses up all the CPU without actually making the CPU do anything, so other processes can't use the CPU and produce more heat than it can handle.
  - neogodless 5y ago
    Wow! This brings back memories. I don't remember which generation of CPUs this was.. maybe Pentium III or AthlonXP. But there was an issue in Windows where the chip would overheat when idle. There was an app called Rain that you could download and it would just keep the idle process from running away and causing heat. I may need to research this on my lunch break and report back. EDIT: Here's a related thread: https://arstechnica.com/civis/viewtopic.php?f=8&t=1060257 https://arstechnica.com/civis/viewtopic.php?f=8&t=1060257
    - vikingerik 5y ago
      That wasn't exactly an issue, more like a feature that didn't exist yet. The Pentium IIIs were the first CPUs that could consume enough power to cause heat problems if not throttled. OSes didn't yet anticipate that; they didn't yet have the concept of issuing halt instructions when there was no application work to do, they just let the CPU spin faster on a waiting-for-message loop. The OS makers soon recognized the need, and halting the CPU became built in to the OS by the time of either Windows 98 or 2000, so yeah, in the interim, tools like Rain were what you used.
  - causi 5y ago
    That's very interesting. I didn't know it was possible for a process to use the CPU without using the CPU, as it were. Rather I thought the CPU usage was more or less a direct measurement.
    - vnorilo 5y ago
      From [1] On processors that have a halt instruction that stops the CPU until an interrupt occurs, such as x86's HLT instruction, it may save significant amounts of power and heat if the idle task consists of a loop which repeatedly executes HLT instructions. -- I don't know how it is implemented in darwin, HLT is a privileged instruction, then again it's kernel_task. 1: https://en.m.wikipedia.org/wiki/Idle_(CPU) https://en.m.wikipedia.org/wiki/Idle_(CPU)
    - remram 5y ago
      I would expect that the CPU frequency would throttle down, rather than regularly running halt instructions.
  - shrx 5y ago
    Documented here: https://support.apple.com/en-us/HT207359 https://support.apple.com/en-us/HT207359
    - wongarsu 5y ago
      > One of the functions of kernel_task is to help manage CPU temperature by making the CPU less available to processes that are using it intensely. In other words, kernel_task responds to conditions that cause your CPU to become too hot If it's about CPU temperature, why does Apple schedule a task instead of just downclocking the CPU, like everyone else? This question predates the release of M1 Macbooks, and everyone else does thermal management of Intel Core processors via clock speed, not artificial idle load.
      - p_l 5y ago
        The high cpu usage is essentially the evidence for running certain power-saving measures that "look" like the task is using a lot of CPU time (it does, sleeping the cpu). There's similar behaviour on linux but it shows as specific kernel threads related to intel power throttling, so it's more obvious what's happening.
      - majou 5y ago
        It would reduce latency of tasks to do it this way.
      - spuz 5y ago
        They almost certainly do adjust CPU frequency as well (although I don't have a 2020 Mac to check this). Lowering the frequency would mean fewer instructions can be processed per second which means you are more likely to see a higher CPU usage for all tasks. What you see is probably the combination of both of these effects. It's annoying that the process monitor does not provide any way to distinguish high CPU load due to demand and high CPU load due to a low clock frequency but there is software that can display a CPU frequency chart which can give some insight: https://pietschsoft.com/post/2020/02/15/macos-monitor-cpu-usage-info https://pietschsoft.com/post/2020/02/15/macos-monitor-cpu-us...
xgbi 5y ago
This doesn't make sense, and I'm a bit worried: I "cheaped" out and have a "left side only USB-C" MBPro from 2019. Should I understand that having any kind of load on the measly 2 ports I have on my 1600€ computer will lead to abysmal performance? Like, attaching a USB hub to add basic necessity like HDMI or USB A?
- WA 5y ago
  Attach an LG Ultrafine 5K and you can fry an egg on your €3,300 laptop and use the white noise from the fan to sleep well.
  - danlugo92 5y ago
    Attach the same monitor to both an M1 and an Intel Laptop, you can fry chicken on the latter.
    - gambiting 5y ago
      Can you? My i5-10300H equipped laptop drives two external monitors daily and the fans don't even start in normal use. Maybe specify which laptop? The M1 can't even support two monitors plugged in directly, which is a joke for a machine this expensive.
      - deleted 5y ago
        [deleted]
      - formerly_proven 5y ago
        I've had dual-head on 12? 13? year old laptops - no problem (not HiDPI, which was not a thing then, obviously, but FHD or WQHD). Currently doing the same with an i5-8350U, runs passively most of the time.
      - deleted 5y ago
        [deleted]
      - ansible 5y ago
kuu 5y ago
How does something like this happen without QA knowing and Apple fixing it? I mean, it's happening cause charging it, that's something all users will do :S Sounds a lot like the antennagate
- whywhywhywhy 5y ago
  They spotted it and made the trade off that it wasn’t worth fixing
  - nkozyra 5y ago
    Or alternately, spotted it and decided to make their own chip.
    - millzlane 5y ago
      Or no one has ever submitted a bug report. :-) https://tidbits.com/2020/06/17/how-to-report-bugs-to-apple-so-they-get-fixed/ https://tidbits.com/2020/06/17/how-to-report-bugs-to-apple-s...
Pelam 5y ago
I have set up several macs to spin up the fans more aggressively. Subjectively this seems to help a lot. And the noise is not much worse, because eventually they spin at full blast anyway; just a bit too late when presumably thermal throttling is already hitting.
- officeplant 5y ago
  yep, started using smcfancontrol in 2008 due to Jobs insistence on silent horrible stock fan curves. Only stopped due to M1 Mini's not needing my input on fan speed.
ordiel 5y ago
Apple hardware quality and the design decisions have gone to shit since jobs died. The folks thet were feed up with the hype of his return to a diying company (and with a good reason, since the company really improved) are the ones keeping the company alive... In my opinion unless something changes it wont take long for it to be the dying company they use to be... They have a grat "body" but they lack the "heart" (and apparently the brain also)
- drclau 5y ago
  Yeah, Apple hardware may be worse than it used to be. But as far as I can tell, it's still at the top. Can you point out a company that consistently makes better hardware than Apple does?
  - jimmaswell 5y ago
    Literally any random gaming laptop on Amazon probably won't have any of these problems, while also having ethernet ports etc.
    - zepolen 5y ago
      They'd also cost half as much and allow you to upgrade disk and ram.
YXNjaGVyZWdlbgo 5y ago
On my HP Envy x360 (2020 - AMD Ryzen) I got the same problem if the power is going through a USB-C Hub. My thermals are 10 degrees higher while charging through USB-C than when charging through the barrel connector.
lewisjoe 5y ago
This is the reason I have a couple of monitors lying uselessly on my table. Everytime I connect an external monitor, it makes the GPU go crazy and overheats the Macbook enough to summon this kernel_task demon. Couldn't comprehend why one of the best laptops on the planet cannot handle one external monitor.
- Tagbert 5y ago
  When you attach an external monitor, that switches from using the Intel integrated GPU to the AMD discrete GPU which uses a lot more power.
thrower123 5y ago
At least Apple realized USB-C only was a stupid idea after a couple of years and reverted...
throwaway2077 5y ago
how the fuck was that problem not caught very early on into development?
- millzlane 5y ago
  I could imagine like 5 ways.
  - throwaway2077 5y ago
    it is a product notorious for severe heat dissipation issues, so I'm picturing extensive tests being done in development, and yet nobody noticing it
millzlane 5y ago
Strange. The proprietary software you run after you perform a repair has a specific port requirement and you can only use the left side ports. I always wondered what was so special about these ports.
throwawaymanbot 5y ago
the 2019 MBP 13" is garbage. All sorts of wacky issues with it. I did read that they made the chassis for a different chip that was delayed, and thus anyone who owns one of these, ends up with a chassis that struggles to cool a completely different chip than what was planned. (Im not sure this causes all the other issues however)
somedude895 5y ago
Before I found this solution, my MBP would basically hang up with the fan going crazy whenever I'd have an MS Teams call. It still feels ridiculous when it happens and I switch plugs. It feels like such a strange thing to have to do on a pricey device like this.
cwoolfe 5y ago
I noticed my 2019 MacBook Pro physically hot to touch even after being idle for 8 hours at night. Now I unplug my USB-C monitor and USB-C-to-USB-A adapter at the end of the day and that has solved the problem. Now when I come to the machine in the morning, it is nice and cool, and I plug-in my peripherals again. It seems Apple has noticed this sub-par pro performance and moved back to the MagSafe charger in the latest pro models. Also, for the cynical among us, I would like to point out that each issue I've had with a MacBook, Apple has fixed for free. Don't assume they wont fix it until you take it to the Apple Store and ask.
- counternotions 5y ago
  Was there an Apple Store response for the overheating / overnight-charging problem?
  - cwoolfe 5y ago
    I didn't ask them about the heat issue since I attributed the issue to my cheap non-Apple adapters. Issues they've fixed for me for free: broken back-plate on the old 2010 white unibody macbook, as well as a stuck key on keyboard of 2018 Macbook Pro.
- jjav 5y ago
  > I noticed my 2019 MacBook Pro physically hot to touch even after being idle for 8 hours at night. My late-2020 MacBook Pro also stays warm (even hot, sometimes) while supposedly sleeping. It can also no longer charge on the right side, that just stopped working. Had to rearrange my desk to satisfy the power bugs on the laptop. Quality has gone way down, I don't quite see myself ever getting a Mac laptop again, after being on OSX laptops ever since OSX 10.0 came out.
mzzter 5y ago
Non-obvious debugging involving a mental model of the physical world reminds me somewhat of “the case of the 500 mile email” [0] [0] https://www.ibiblio.org/harris/500milemail.html https://www.ibiblio.org/harris/500milemail.html
hammock 5y ago
I run a displayport hub connected to a M1 MacBook pro and i noticed it crashes sometimes when in the back port. So i have to keep it in the front port.
19h 5y ago
Previous discussion: https://news.ycombinator.com/item?id=28733467 https://news.ycombinator.com/item?id=28733467 Also why is that submission now marked as a dupe? It doesn't even point to the one that it is supposed to be a dupe of.
CRConrad 5y ago
And here I thought this was about charging electric cars: "Audi thoughtfully put charging points in both fenders, but only the right one is suitable for high-speed use." -- https://www.cnet.com/roadshow/reviews/2022-audi-rs-e-tron-gt-review/ https://www.cnet.com/roadshow/reviews/2022-audi-rs-e-tron-gt... (Picture caption, about pic #4 from the top.)
telesilla 5y ago
Earlier this year, suddenly had my 2017 MacBook pro freak out and freeze on using the camera or screenshare: fans would go nuts and cpu meters were completely loaded. After reinstalling and upgrading the OS with no luck it occurred to me to check for dust. Indeed, there was much dust and after a good proper clean all is normal again. I used compressed air for best results.
bob229 5y ago
The build quality of macs are actually abysmal

high CPU usage by kernel_task is caused by high Thunderbolt Left Proximity temperature, which is caused by charging and having normal peripherals plugged in at the same time. Did anyone ever figure out why exactly the temperature sensor was making kernel_task go crazy?

mkl 5y ago
The comment by jksoegaard may explain it: "the purpose of the thread is to force idleness". I guess it uses up all the CPU without actually making the CPU do anything, so other processes can't use the CPU and produce more heat than it can handle.
- neogodless 5y ago
  Wow! This brings back memories. I don't remember which generation of CPUs this was.. maybe Pentium III or AthlonXP. But there was an issue in Windows where the chip would overheat when idle. There was an app called Rain that you could download and it would just keep the idle process from running away and causing heat. I may need to research this on my lunch break and report back. EDIT: Here's a related thread: https://arstechnica.com/civis/viewtopic.php?f=8&t=1060257 https://arstechnica.com/civis/viewtopic.php?f=8&t=1060257
  - vikingerik 5y ago
    That wasn't exactly an issue, more like a feature that didn't exist yet. The Pentium IIIs were the first CPUs that could consume enough power to cause heat problems if not throttled. OSes didn't yet anticipate that; they didn't yet have the concept of issuing halt instructions when there was no application work to do, they just let the CPU spin faster on a waiting-for-message loop. The OS makers soon recognized the need, and halting the CPU became built in to the OS by the time of either Windows 98 or 2000, so yeah, in the interim, tools like Rain were what you used.
- causi 5y ago
  That's very interesting. I didn't know it was possible for a process to use the CPU without using the CPU, as it were. Rather I thought the CPU usage was more or less a direct measurement.
  - vnorilo 5y ago
    From [1] On processors that have a halt instruction that stops the CPU until an interrupt occurs, such as x86's HLT instruction, it may save significant amounts of power and heat if the idle task consists of a loop which repeatedly executes HLT instructions. -- I don't know how it is implemented in darwin, HLT is a privileged instruction, then again it's kernel_task. 1: https://en.m.wikipedia.org/wiki/Idle_(CPU) https://en.m.wikipedia.org/wiki/Idle_(CPU)
  - remram 5y ago
    I would expect that the CPU frequency would throttle down, rather than regularly running halt instructions.
- shrx 5y ago
  Documented here: https://support.apple.com/en-us/HT207359 https://support.apple.com/en-us/HT207359
  - wongarsu 5y ago
    > One of the functions of kernel_task is to help manage CPU temperature by making the CPU less available to processes that are using it intensely. In other words, kernel_task responds to conditions that cause your CPU to become too hot If it's about CPU temperature, why does Apple schedule a task instead of just downclocking the CPU, like everyone else? This question predates the release of M1 Macbooks, and everyone else does thermal management of Intel Core processors via clock speed, not artificial idle load.
    - p_l 5y ago
      The high cpu usage is essentially the evidence for running certain power-saving measures that "look" like the task is using a lot of CPU time (it does, sleeping the cpu). There's similar behaviour on linux but it shows as specific kernel threads related to intel power throttling, so it's more obvious what's happening.
    - majou 5y ago
      It would reduce latency of tasks to do it this way.
    - spuz 5y ago
      They almost certainly do adjust CPU frequency as well (although I don't have a 2020 Mac to check this). Lowering the frequency would mean fewer instructions can be processed per second which means you are more likely to see a higher CPU usage for all tasks. What you see is probably the combination of both of these effects. It's annoying that the process monitor does not provide any way to distinguish high CPU load due to demand and high CPU load due to a low clock frequency but there is software that can display a CPU frequency chart which can give some insight: https://pietschsoft.com/post/2020/02/15/macos-monitor-cpu-usage-info https://pietschsoft.com/post/2020/02/15/macos-monitor-cpu-us...

xgbi 5y ago

This doesn't make sense, and I'm a bit worried: I "cheaped" out and have a "left side only USB-C" MBPro from 2019. Should I understand that having any kind of load on the measly 2 ports I have on my 1600€ computer will lead to abysmal performance? Like, attaching a USB hub to add basic necessity like HDMI or USB A?

WA 5y ago
Attach an LG Ultrafine 5K and you can fry an egg on your €3,300 laptop and use the white noise from the fan to sleep well.
- danlugo92 5y ago
  Attach the same monitor to both an M1 and an Intel Laptop, you can fry chicken on the latter.
  - gambiting 5y ago
    Can you? My i5-10300H equipped laptop drives two external monitors daily and the fans don't even start in normal use. Maybe specify which laptop? The M1 can't even support two monitors plugged in directly, which is a joke for a machine this expensive.
    - deleted 5y ago
      [deleted]
    - formerly_proven 5y ago
      I've had dual-head on 12? 13? year old laptops - no problem (not HiDPI, which was not a thing then, obviously, but FHD or WQHD). Currently doing the same with an i5-8350U, runs passively most of the time.
    - deleted 5y ago
      [deleted]
    - ansible 5y ago

kuu 5y ago

How does something like this happen without QA knowing and Apple fixing it? I mean, it's happening cause charging it, that's something all users will do :S Sounds a lot like the antennagate

whywhywhywhy 5y ago
They spotted it and made the trade off that it wasn’t worth fixing
- nkozyra 5y ago
  Or alternately, spotted it and decided to make their own chip.
  - millzlane 5y ago
    Or no one has ever submitted a bug report. :-) https://tidbits.com/2020/06/17/how-to-report-bugs-to-apple-so-they-get-fixed/ https://tidbits.com/2020/06/17/how-to-report-bugs-to-apple-s...

Pelam 5y ago

I have set up several macs to spin up the fans more aggressively. Subjectively this seems to help a lot. And the noise is not much worse, because eventually they spin at full blast anyway; just a bit too late when presumably thermal throttling is already hitting.

officeplant 5y ago
yep, started using smcfancontrol in 2008 due to Jobs insistence on silent horrible stock fan curves. Only stopped due to M1 Mini's not needing my input on fan speed.

ordiel 5y ago

Apple hardware quality and the design decisions have gone to shit since jobs died. The folks thet were feed up with the hype of his return to a diying company (and with a good reason, since the company really improved) are the ones keeping the company alive... In my opinion unless something changes it wont take long for it to be the dying company they use to be... They have a grat "body" but they lack the "heart" (and apparently the brain also)

drclau 5y ago
Yeah, Apple hardware may be worse than it used to be. But as far as I can tell, it's still at the top. Can you point out a company that consistently makes better hardware than Apple does?
- jimmaswell 5y ago
  Literally any random gaming laptop on Amazon probably won't have any of these problems, while also having ethernet ports etc.
  - zepolen 5y ago
    They'd also cost half as much and allow you to upgrade disk and ram.

YXNjaGVyZWdlbgo 5y ago

On my HP Envy x360 (2020 - AMD Ryzen) I got the same problem if the power is going through a USB-C Hub. My thermals are 10 degrees higher while charging through USB-C than when charging through the barrel connector.

lewisjoe 5y ago

This is the reason I have a couple of monitors lying uselessly on my table. Everytime I connect an external monitor, it makes the GPU go crazy and overheats the Macbook enough to summon this kernel_task demon. Couldn't comprehend why one of the best laptops on the planet cannot handle one external monitor.

Tagbert 5y ago
When you attach an external monitor, that switches from using the Intel integrated GPU to the AMD discrete GPU which uses a lot more power.

thrower123 5y ago

At least Apple realized USB-C only was a stupid idea after a couple of years and reverted...

throwaway2077 5y ago

how the fuck was that problem not caught very early on into development?

millzlane 5y ago
I could imagine like 5 ways.
- throwaway2077 5y ago
  it is a product notorious for severe heat dissipation issues, so I'm picturing extensive tests being done in development, and yet nobody noticing it

millzlane 5y ago

Strange. The proprietary software you run after you perform a repair has a specific port requirement and you can only use the left side ports. I always wondered what was so special about these ports.

throwawaymanbot 5y ago

the 2019 MBP 13" is garbage. All sorts of wacky issues with it. I did read that they made the chassis for a different chip that was delayed, and thus anyone who owns one of these, ends up with a chassis that struggles to cool a completely different chip than what was planned. (Im not sure this causes all the other issues however)

somedude895 5y ago

Before I found this solution, my MBP would basically hang up with the fan going crazy whenever I'd have an MS Teams call. It still feels ridiculous when it happens and I switch plugs. It feels like such a strange thing to have to do on a pricey device like this.

cwoolfe 5y ago

I noticed my 2019 MacBook Pro physically hot to touch even after being idle for 8 hours at night. Now I unplug my USB-C monitor and USB-C-to-USB-A adapter at the end of the day and that has solved the problem. Now when I come to the machine in the morning, it is nice and cool, and I plug-in my peripherals again. It seems Apple has noticed this sub-par pro performance and moved back to the MagSafe charger in the latest pro models. Also, for the cynical among us, I would like to point out that each issue I've had with a MacBook, Apple has fixed for free. Don't assume they wont fix it until you take it to the Apple Store and ask.

counternotions 5y ago
Was there an Apple Store response for the overheating / overnight-charging problem?
- cwoolfe 5y ago
  I didn't ask them about the heat issue since I attributed the issue to my cheap non-Apple adapters. Issues they've fixed for me for free: broken back-plate on the old 2010 white unibody macbook, as well as a stuck key on keyboard of 2018 Macbook Pro.
jjav 5y ago
> I noticed my 2019 MacBook Pro physically hot to touch even after being idle for 8 hours at night. My late-2020 MacBook Pro also stays warm (even hot, sometimes) while supposedly sleeping. It can also no longer charge on the right side, that just stopped working. Had to rearrange my desk to satisfy the power bugs on the laptop. Quality has gone way down, I don't quite see myself ever getting a Mac laptop again, after being on OSX laptops ever since OSX 10.0 came out.

mzzter 5y ago

Non-obvious debugging involving a mental model of the physical world reminds me somewhat of “the case of the 500 mile email” [0] [0] https://www.ibiblio.org/harris/500milemail.html https://www.ibiblio.org/harris/500milemail.html

hammock 5y ago

I run a displayport hub connected to a M1 MacBook pro and i noticed it crashes sometimes when in the back port. So i have to keep it in the front port.

19h 5y ago

Previous discussion: https://news.ycombinator.com/item?id=28733467 https://news.ycombinator.com/item?id=28733467 Also why is that submission now marked as a dupe? It doesn't even point to the one that it is supposed to be a dupe of.

CRConrad 5y ago

And here I thought this was about charging electric cars: "Audi thoughtfully put charging points in both fenders, but only the right one is suitable for high-speed use." -- https://www.cnet.com/roadshow/reviews/2022-audi-rs-e-tron-gt-review/ https://www.cnet.com/roadshow/reviews/2022-audi-rs-e-tron-gt... (Picture caption, about pic #4 from the top.)

telesilla 5y ago

Earlier this year, suddenly had my 2017 MacBook pro freak out and freeze on using the camera or screenshare: fans would go nuts and cpu meters were completely loaded. After reinstalling and upgrading the OS with no luck it occurred to me to check for dust. Indeed, there was much dust and after a good proper clean all is normal again. I used compressed air for best results.

bob229 5y ago

The build quality of macs are actually abysmal