4 ms·

Twice the cores leads me to think we're getting ecores

_hypx_ 3y ago
I think so too.
0cf8612b2e1e 3y ago
Does Linux have mechanisms in place to properly utilize ecores? Specifically tagging background services so they never jump in priority? Or would it be up to me to manually assign affinity? I read somewhere that part of what makes the iOS experience better is tight control over how much CPU background jobs can steal.
- lights0123 3y ago
  Linux has had support for cores with different capabilities for ~a decade, when arm introduced big.LITTLE. systemd puts background services in "slices", which can have properties set in bulk. systemctl set-property system.slice AllowedCPUs=16-19 Would set the "system" slice to certain pinned cores, but there's nothing automatic.
  - 0cf8612b2e1e 3y ago
    That’s interesting and easy enough to experiment. While I do not have mixed performance cores, I have been curious if pinning processes results in any noticeable smoothness. I get annoyed at various Gnome garbage that occasionally thrashes.
  - noir_lord 3y ago
    also has taskset which just lets you say "this PID can run on cores 0 through 13". Not the friendliest mechanism for defining what runs on what but it's what I use to make sure that server software I really want on the P cores stays on the P cores.
- garaetjjte 3y ago
  https://docs.kernel.org/scheduler/sched-capacity.html https://docs.kernel.org/scheduler/sched-capacity.html https://docs.kernel.org/scheduler/sched-energy.html https://docs.kernel.org/scheduler/sched-energy.html
scheme271 3y ago
I don't think it's e-cores so much as a Zen 5 version of the Zen 4c cores. So smaller L3 (the 4c has half the L3 that the Zen 4 has) and slower clocks. But the compact cores are half of the size of the regular cores and about 75% of the power. The key point is that the cores are otherwise the same so you don't have the weird intel situation where the e-cores don't support the same instructions as the p-cores.
- skavi 3y ago
  > the weird intel situation where the e-cores don't support the same instructions as the p-cores Intel didn’t have this problem. They simply disabled instructions available on P and not on E. They did face the scheduling issues inherent in heterogenous systems. But so will AMD.
cjbgkagh 3y ago
I'm happy so long as it can score really high in Cinebench, which is probably the most relevant benchmark for my work.
mlyle 3y ago
From the article: > We don't know yet what types of cores these new Zen 5 core clusters will have. Half of Zen 5's core count could be dedicated entirely to Zen 5c efficiency cores, or the entire stack could be vanilla Zen 5 performance cores. It could be a mix of both since AMD's slides suggest that there will be different models featuring FP-512 support and some models with low-power cores.

I think so too.

Does Linux have mechanisms in place to properly utilize ecores? Specifically tagging background services so they never jump in priority? Or would it be up to me to manually assign affinity? I read somewhere that part of what makes the iOS experience better is tight control over how much CPU background jobs can steal.

lights0123 3y ago
Linux has had support for cores with different capabilities for ~a decade, when arm introduced big.LITTLE. systemd puts background services in "slices", which can have properties set in bulk. systemctl set-property system.slice AllowedCPUs=16-19 Would set the "system" slice to certain pinned cores, but there's nothing automatic.
- 0cf8612b2e1e 3y ago
  That’s interesting and easy enough to experiment. While I do not have mixed performance cores, I have been curious if pinning processes results in any noticeable smoothness. I get annoyed at various Gnome garbage that occasionally thrashes.
- noir_lord 3y ago
  also has taskset which just lets you say "this PID can run on cores 0 through 13". Not the friendliest mechanism for defining what runs on what but it's what I use to make sure that server software I really want on the P cores stays on the P cores.
garaetjjte 3y ago
https://docs.kernel.org/scheduler/sched-capacity.html https://docs.kernel.org/scheduler/sched-capacity.html https://docs.kernel.org/scheduler/sched-energy.html https://docs.kernel.org/scheduler/sched-energy.html

scheme271 3y ago

I don't think it's e-cores so much as a Zen 5 version of the Zen 4c cores. So smaller L3 (the 4c has half the L3 that the Zen 4 has) and slower clocks. But the compact cores are half of the size of the regular cores and about 75% of the power. The key point is that the cores are otherwise the same so you don't have the weird intel situation where the e-cores don't support the same instructions as the p-cores.

skavi 3y ago
> the weird intel situation where the e-cores don't support the same instructions as the p-cores Intel didn’t have this problem. They simply disabled instructions available on P and not on E. They did face the scheduling issues inherent in heterogenous systems. But so will AMD.

cjbgkagh 3y ago

I'm happy so long as it can score really high in Cinebench, which is probably the most relevant benchmark for my work.

mlyle 3y ago

From the article: > We don't know yet what types of cores these new Zen 5 core clusters will have. Half of Zen 5's core count could be dedicated entirely to Zen 5c efficiency cores, or the entire stack could be vanilla Zen 5 performance cores. It could be a mix of both since AMD's slides suggest that there will be different models featuring FP-512 support and some models with low-power cores.