New Intel Patch Series To Further Help Alder Lake / Hybrid CPUs On Linux

[phoronix]

Phoronix: New Intel Patch Series To Further Help Alder Lake / Hybrid CPUs On Linux

In the year since Intel announced 12th Gen Core "Alder Lake" processors there have been a number of patches tuning the Linux kernel's scheduler and other code to better deal with the mix of the performance and efficient cores. While that looked to be all buttoned up for a number of months now with Alder Lake CPUs performing well on Linux, another patch series further adjusting the Linux sched/fair code was published to help with these Intel hybrid processor designs...

https://www.phoronix.com/news/Intel-ITM3-Sched-More-Hybrid

[MadCatX]

I love how none of the Linux patches for ADL scheduling posted so far mention the supposedly invaluable Thread Director thingy. Almost gives you the feeling that it's useless.

Sorry, I had to...

[birdie]

Looks like in a year or two the Linux kernel will finally properly and fully support ADL's hybrid architecture. Oh, wait, no one has even begun to work on userspace support.

[MadCatX]

Looks like in a year or two the Linux kernel will finally properly and fully support ADL's hybrid architecture. Oh, wait, no one has even begun to work on userspace support.

And the tragic impact of that is that Linux beats Win11 on ADL in almost every benchmark (https://www.phoronix.com/review/wind...nux-mid22adl/7)

[MorrisS.]

How many bugs affect Intel CPUs? Is there a list?

[Volta]

And the tragic impact of that is that Linux beats Win11 on ADL in almost every benchmark (https://www.phoronix.com/review/wind...nux-mid22adl/7)

With newer kernel and performance CPU governor it will be even more drastic for winboys.

[birdie]

How many bugs affect Intel CPUs? Is there a list?

What bugs? Transient execution vulnerabilities? Erratas? Do you imply that AMD CPUs are without issues? Well, sorry to break it to you but all AMD CPUs are affected by Spectre-class vulnerabilities and then some of their own.

Here's a nice overview, though it's a tad incomplete because it's grown out of control: https://en.wikipedia.org/wiki/Transi...ulnerabilities

Here's a list of CVEs related to Intel but very few of them are CPU specific: https://www.cvedetails.com/vendor/238/

An Intel's own list of various vulnerabilities: https://www.intel.com/content/www/us...cpu-model.html

The most recent Retbleed vulnerability affects only quite old Intel CPU uArchs (with Skylake released in 2015 being the last) but it affects both Zen 1(+) and Zen 2 (uArchs)

[Solid State Brain]

I love how none of the Linux patches for ADL scheduling posted so far mention the supposedly invaluable Thread Director thingy. Almost gives you the feeling that it's useless.

They already gave support to it (i.e. what they call the Intel HFI / Hardware Feedback Interface), but it seems it needs to be put into actual work via user-space tools that haven't been written yet. Integration into the kernel scheduler seems unlikely.

[skeevy420]

I love how none of the Linux patches for ADL scheduling posted so far mention the supposedly invaluable Thread Director thingy. Almost gives you the feeling that it's useless.

Sorry, I had to...

And ACTION

To be 20

Or GOTO 10

That is the question.

CUT!!!

[birdie]

They already gave support to it (i.e. what they call the Intel HFI / Hardware Feedback Interface), but it seems it needs to be put into actual work via user-space tools that haven't been written yet. Integration into the kernel scheduler seems unlikely.

Just like with userspace OOM managers (earlyoom, systemd-oomd, etc.) such a thing doesn't belong to the kernel. It needs to be easilily manageable and updateable.