We found the Missing Performance: Zen 5 Tested with SMT Disabled

https://www.techpowerup.com/review/amd-ryzen-9-9700x-performance-smt-disabled/

133 points · 11 comments · view on lemmy.world

11 Comments

conciselyverbose@sh.itjust.works · 71 pts · 2y (8 replies)

During the course of our testing, we observed that Windows 11 was scheduling workloads on the 9700X in a manner that would try to saturate a single core first, by placing workloads on each of its logical threads.

🤦‍♀️

jlh@lemmy.jlh.name · 58 pts · 2y

it's obviously a scheduler/p-state bug in windows, look at the Linux performance

https://www.phoronix.com/review/ryzen-9600x-9700x

adarza@lemmy.ca · 31 pts · 2y (6 replies)

so, basically, the os isn't tuned for the new chips yet.

the 2nd threads on smt-enabled cores are supposed to get hit last.

conciselyverbose@sh.itjust.works · 25 pts · 2y (3 replies)

It's an easy fix, sure.

But there are 3 manufacturers for them to schedule for. It should be ready way before anything ships.

ag10n@lemmy.world · 63 pts · 2y (2 replies)

Copilot and ads taking up development cycles

catloaf@lemm.ee · 15 pts · 2y (1 reply)

Actually, yeah, probably. CPU scheduling isn't the shiny new thing, nor something that gets that sweet, sweet monthly recurring revenue. So, it doesn't get prioritized.

floofloof@lemmy.ca · 2 pts · 2y

Microsoft always operates like this. Whatever bullshit management demands for marketing purposes takes the resources away from basic stability and quality improvements. Sometimes this results in quite predictable disaster:

Microsoft Chose Profit Over Security and Left U.S. Government Vulnerable to Russian Hack, Whistleblower Says

SomeoneSomewhere@lemmy.nz · 13 pts · 2y

There should be no need for tuning, tweaking, or optimizing on functionality this basic.

If you ask the processor, it will spit out a graph like this telling you what threads/cores share resources, all the way up to (on large or server platforms) some RAM or PCIe slots being closer to certain groups of cores.

barsoap@lemm.ee · 3 pts · 2y

For values of "new chips" that include 20 year old ones. Foster was released 2001, the chips were single-core but you could have up to eight on a board so it's still multi-core SMT. First on-die multi-core SMT seemed to have been Paxville, 2005.

Or maybe Windows server has a proper scheduler and they never bothered bringing it to desktops?

schizo@forum.uncomfortable.business · 64 pts · 2y

This is shockingly stupid. SMT has been a thing on x86 long enough for it to be able to buy it's own alcohol and yet somehow the windows scheduler STILL can't fucking deal with it?

I'm not a kernel-level developer or anything but I mean, at some point you have to wonder how fucking trash windows kernel internals are that this problem keeps happening over and over and over and.....

JRepin@lemmy.ml · 35 pts · 2y (1 reply)

Or they just found out that Windows process scheduler is still broken beyond repair. If you look at the benchmarks on GNU/Linux performance is all there. For example see Phoronix benchmark

MishMash@lemm.ee · 0 pts · 2y
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drbluefall@toast.ooo · 1 pts · 2y
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