5 ms·

> This was caused by a software upgrade of the Linux kernel, which increased the average power use of the server from 1.19 to 1.49 watts I wonder what change i

> This was caused by a software upgrade of the Linux kernel, which increased the average power use of the server from 1.19 to 1.49 watts I wonder what change in the linux kernel caused the increased load. Someone out there is responsible for this crime!

deleted 5y ago
[deleted]
ralph84 5y ago
This is an area where Apple is way ahead of everyone else. A code change that increases power usage 25% wouldn’t make it past CI at Apple.
- jolux 5y ago
  That's incredible. How do they measure that? Does their CI somehow measure power impact on a set of real devices?
  - ruffrey 5y ago
    Apple is designing much of the silicon. Measuring power usage is a core competency.
- CraigJPerry 5y ago
  How many more hardware configurations is Linux deployed on than MacOS? Would it be in the region of 3-4 orders of magnitude more hardware configurations? How long has there been a power consumption focus in the linux kernel? The efforts to reduce power usage by the linux kernel pre-date PowerTOP’s first release and wiki tells me that was 2006. Is Apple way ahead or is it just less popular?
  - jolux 5y ago
    > Is Apple way ahead or is it just less popular? They're definitely solving a narrower problem but they do appear to have it solved. Is there even a subset of hardware configurations for which this is the case with Linux? (if there is I would love to know about it)
    - r-w 5y ago
      > Is there even a subset of hardware configurations for which this is the case with Linux? That's not how cross-platform, cross-application software works. Linux is used for everything. Every other change for power efficiency will get balanced out by another change for raw performance.
      - jolux 5y ago
        Well sure but there are vendors that advertise Linux computers.
- goodpoint 5y ago
  On the contrary. Linux runs on any Android or FLOSS phone, almost every car and plane, TV, router, and plenty of industrial devices. The amount of testing that Linux goes through is staggering. This has to be a specific bug on that platform in its specific configuration.
- user_7832 5y ago
  Sorry, what does CI stand for?
  - TobTobXX 5y ago
    Continuous integration -- Software development practice based on frequent submission of granular changes https://en.wikipedia.org/wiki/Continuous_integration https://en.wikipedia.org/wiki/Continuous_integration ... basically check every small commit, ideally end-to-end.
    - user_7832 5y ago
      Thanks!
- jshier 5y ago
  I find that hard to believe considering everything else that makes it past not only Apple's CI, but their automatic and manual QA testing, their beta process, and multiple public releases. I know they have to do something in their CI, but I'd like to see any evidence of your claim.
- driverdan 5y ago
  [citation needed]
davidcuddeback 5y ago
Perhaps Spectre/Meltdown mitigations?
nijave 5y ago
Could be a scheduler change. I think the default scheduler doesn't try too hard to be power efficient on the assumption servers/desktops generally aren't optimizing for a single watt or less On Android, the scheduler can have a decent impact battery life

deleted 5y ago

[deleted]

ralph84 5y ago

This is an area where Apple is way ahead of everyone else. A code change that increases power usage 25% wouldn’t make it past CI at Apple.

jolux 5y ago
That's incredible. How do they measure that? Does their CI somehow measure power impact on a set of real devices?
- ruffrey 5y ago
  Apple is designing much of the silicon. Measuring power usage is a core competency.
CraigJPerry 5y ago
How many more hardware configurations is Linux deployed on than MacOS? Would it be in the region of 3-4 orders of magnitude more hardware configurations? How long has there been a power consumption focus in the linux kernel? The efforts to reduce power usage by the linux kernel pre-date PowerTOP’s first release and wiki tells me that was 2006. Is Apple way ahead or is it just less popular?
- jolux 5y ago
  > Is Apple way ahead or is it just less popular? They're definitely solving a narrower problem but they do appear to have it solved. Is there even a subset of hardware configurations for which this is the case with Linux? (if there is I would love to know about it)
  - r-w 5y ago
    > Is there even a subset of hardware configurations for which this is the case with Linux? That's not how cross-platform, cross-application software works. Linux is used for everything. Every other change for power efficiency will get balanced out by another change for raw performance.
    - jolux 5y ago
      Well sure but there are vendors that advertise Linux computers.
goodpoint 5y ago
On the contrary. Linux runs on any Android or FLOSS phone, almost every car and plane, TV, router, and plenty of industrial devices. The amount of testing that Linux goes through is staggering. This has to be a specific bug on that platform in its specific configuration.
user_7832 5y ago
Sorry, what does CI stand for?
- TobTobXX 5y ago
  Continuous integration -- Software development practice based on frequent submission of granular changes https://en.wikipedia.org/wiki/Continuous_integration https://en.wikipedia.org/wiki/Continuous_integration ... basically check every small commit, ideally end-to-end.
  - user_7832 5y ago
    Thanks!
jshier 5y ago
I find that hard to believe considering everything else that makes it past not only Apple's CI, but their automatic and manual QA testing, their beta process, and multiple public releases. I know they have to do something in their CI, but I'd like to see any evidence of your claim.
driverdan 5y ago
[citation needed]

davidcuddeback 5y ago

Perhaps Spectre/Meltdown mitigations?

nijave 5y ago

Could be a scheduler change. I think the default scheduler doesn't try too hard to be power efficient on the assumption servers/desktops generally aren't optimizing for a single watt or less On Android, the scheduler can have a decent impact battery life