4 ms·

Try to compile ATLAS and you will become intimately familiar with this problem. It refuses to compile if you have any kind of throttling or scaling enabled beca

Try to compile ATLAS and you will become intimately familiar with this problem. It refuses to compile if you have any kind of throttling or scaling enabled because it relies on benchmarking all of the alternative compute kernels to determine which is best for your specific hardware. Just following the instructions in the README to set the governor from userspace is not nearly enough. I had to completely re-compile my kernel with the default governor set to performance, on-demand enabled, and all thermal throttling not even available as an option. The basic issue is consumer kernels are all general-purpose and have to work on laptops and mobile devices, so a whole lot of options are set that make no sense on workstations, and you end up throttling when it isn't necessary, i.e. you're not on battery and you have plenty of fan power or a water loop to prevent actual damage. Heck, in many cases, you may even need to disable throttling in the BIOS, which is doubly disappointing because a desktop BIOS definitely doesn't need settings that work on laptops and mobile.

zinekeller 5y ago
> Heck, in many cases, you may even need to disable throttling in the BIOS, which is doubly disappointing because a desktop BIOS definitely doesn't need settings that work on laptops and mobile. For you, probably, but companies in Asia (due to shareholder and regulatory reasons) needs to power manage their systems hard and only will disable power management when really required. That option exists not for you but for them.
- nonameiguess 5y ago
  Honestly, I had no idea that was the case, but it explains a lot, so thanks.
- mcint 5y ago
  Can you say more? I’m not even sure how I’d search for more information about this. Because of the large and dense population centers, and therefore power requirements, governments require aggressive power management settings on computers??
zekrioca 5y ago
I understand why ATLAS would need to do something like this maybe up until 10 years ago. I also understand the time and performance hard constraints the library needs to provide applications with, specially in some scientific experiments. However, this type of static linking is very weird in today's architectures, specially when considering that an application can run anywhere, from a light bulb to a top notch server hosted in the cloud and elsewhere. It specially bugs me to think that people leading some of these projects are so stubborn to the point of not accepting the new reality imposed by today's software and system architectures.
- sharikone 5y ago
  I agree that refusing to compile is stubborn on their part. But tailoring the build to your system is very valuable, at least as an option. And a big part of the blame lies with the CPU and OS manufacturers that fail to provide good consistent performance measurement options that traverse all the endless layers of abstraction that extend from the transistors to a user space program nowadays
  - genewitch 5y ago
    On the face it seems like CPU manufacturers should be able to put actual performance numbers out; until we realize that the temperature characteristics - and therefore performance - are non-deterministic. This fact allows hardware RNG from thermal emissions on consumer grade CPUs to output at least 3 megabits of 'entropy' per second. The same as 3,000,000 coin flips. I may be misunderstanding what is going on, though.
toast0 5y ago
I certainly understand the need for consistency, but the default throttling regime does offer some benefits. On modern system, the peak speed is usually higher than the consistent speed, so if you're running software with short CPU peaks, you can have better results with throttling than not. Also, if your software doesn't use all the cores, you may be able to run those it does use faster than the consistent speed. Power savings are still useful even when the power comes from the wall, and thermal savings often lead to less noise and can have secondary benefits in conditioned environments. (Of course, there are environments where computers make a good replacement for electrical resistance heaters)
jareklupinski 5y ago
wow you weren't kidding > If ATLAS's configure detects that CPU throttling is enabled, it will kill itself. http://math-atlas.sourceforge.net/atlas_install/node5.html http://math-atlas.sourceforge.net/atlas_install/node5.html a little dramatic but ok

zinekeller 5y ago

> Heck, in many cases, you may even need to disable throttling in the BIOS, which is doubly disappointing because a desktop BIOS definitely doesn't need settings that work on laptops and mobile. For you, probably, but companies in Asia (due to shareholder and regulatory reasons) needs to power manage their systems hard and only will disable power management when really required. That option exists not for you but for them.

nonameiguess 5y ago
Honestly, I had no idea that was the case, but it explains a lot, so thanks.
mcint 5y ago
Can you say more? I’m not even sure how I’d search for more information about this. Because of the large and dense population centers, and therefore power requirements, governments require aggressive power management settings on computers??

zekrioca 5y ago

I understand why ATLAS would need to do something like this maybe up until 10 years ago. I also understand the time and performance hard constraints the library needs to provide applications with, specially in some scientific experiments. However, this type of static linking is very weird in today's architectures, specially when considering that an application can run anywhere, from a light bulb to a top notch server hosted in the cloud and elsewhere. It specially bugs me to think that people leading some of these projects are so stubborn to the point of not accepting the new reality imposed by today's software and system architectures.

sharikone 5y ago
I agree that refusing to compile is stubborn on their part. But tailoring the build to your system is very valuable, at least as an option. And a big part of the blame lies with the CPU and OS manufacturers that fail to provide good consistent performance measurement options that traverse all the endless layers of abstraction that extend from the transistors to a user space program nowadays
- genewitch 5y ago
  On the face it seems like CPU manufacturers should be able to put actual performance numbers out; until we realize that the temperature characteristics - and therefore performance - are non-deterministic. This fact allows hardware RNG from thermal emissions on consumer grade CPUs to output at least 3 megabits of 'entropy' per second. The same as 3,000,000 coin flips. I may be misunderstanding what is going on, though.

toast0 5y ago

I certainly understand the need for consistency, but the default throttling regime does offer some benefits. On modern system, the peak speed is usually higher than the consistent speed, so if you're running software with short CPU peaks, you can have better results with throttling than not. Also, if your software doesn't use all the cores, you may be able to run those it does use faster than the consistent speed. Power savings are still useful even when the power comes from the wall, and thermal savings often lead to less noise and can have secondary benefits in conditioned environments. (Of course, there are environments where computers make a good replacement for electrical resistance heaters)

jareklupinski 5y ago

wow you weren't kidding > If ATLAS's configure detects that CPU throttling is enabled, it will kill itself. http://math-atlas.sourceforge.net/atlas_install/node5.html http://math-atlas.sourceforge.net/atlas_install/node5.html a little dramatic but ok