Windows Task Manager is lying to you, and I don't know how to make it stop

By -

If you use Windows, you might be intimately familiar with Windows Task Manager, which has a performance tab that shows the utilization percentage of various hardware in your system. Today, we're looking at CPU utilization. It looks a bit like this:

The problem is that the meaning of the word utilization is very tricky. There can be multiple meanings:

  1. At the current time, with the current settings, what fraction of time is it executing instructions vs lying idle?
  2. At any time, with the most optimum settings, this CPU could practically complete a number a instructions at a certain rate. What percentage of that rate is it currently working at?
I think the Windows Task Manager is currently using definition #1 above. This is useful for a person to look at the graph and understand "is there a runaway process on my system that is pegging my CPU"? However, consider the alternate use-cases:
  • I am trying to run a long-running program, am I getting my money's worth out of this CPU?
  • I am trying to run a difficult to run program, are there some settings I should change to make this go faster?
  • Is my program optimized properly for the architecture of the CPU I am running it on?
These questions cannot be answered by Task Manager the way it is currently displaying information. I would argue, using definition #2 above would provide a much better answer for these use-cases.

In order to create a UI that effectively displays the utilization according to definition #2 above, it will have to consider the following things:
  • What is the current idle time for each core? (This is common for all definitions).
  • What is the current clock frequency for each core?
  • What is the maximum base clock frequency that each core can sustain long-term?
  • What is the maximum clock frequency that each core can achieve when the CPU decides to Turbo?
  • What is the maximum clock frequency that you can realistically achieve with a stable system if you chose to overclock?
  • Which cores are of what type, distinguishing between performance and efficiency cores?
  • If the CPU supports hyperthreading, which logical cores are actually part of the same physical core?
This is quite difficult, but with a UI that carefully displays this information, I think we can help people make the most of their CPUs.

Comments

Post a Comment

Popular posts from this blog

Laptop Surprises: Lenovo Yoga Slim 7i

By -
I recently bought a Lenovo Yoga Slim 7i (Model 14ITL05). I really like it. I am trying to write down everything that surprised me about the laptop in here. These are mostly things that did not understand about the machine from the product page on Lenovo when ordering. I'll start off with the pleasant surprises: There is some sort of radar sensor on the top on the screen, in the webcam area. When I come and sit on my chair in front of the laptop, it wakes the screen and then Windows Hello logs me in with face ID. This is great! There is a feature called Battery Conservation Mode . What it does is: it pauses charging the battery when it reaches somewhere between 55 and 60%. So you can get the full performance out the CPU without adding a lot of wear on the battery. It allows the CPU to go to full performance with all the wattage coming from the AC adapter without worrying about battery wear. However, I would like to know more about this, and exactly why the battery percent...
Read more

Trouble installing KB2881553

By -
EDIT: The error is back :( These instructions did not help. EDIT 2: The error is mysteriously gone :) I think Microsoft did some magic on their end. I am back on automatic updates! For a long time, I was having trouble installing KB2881553: Update for the English Input Personalization Dictionary on Windows 8.1. These are rough notes on how I resolved it . The problem: KB2881553 is supposed to be only offered on machines that have a touch keyboard with lots of usage. I think it was offered on my desktop accidentally, because I also use a tablet PC with touch on the same Microsoft Account. If you hide the update, it doesn't go away, because a new version of the file is offered on Windows Update within a few days, on the same KB number. The error code was 6B2. The solution: I was mostly guided by this very helpful post . The gist of the problem is that the previous update .msi cannot be found, so you have to convince Microsoft that either (i) your package is up to...
Read more