AMD Ryzen and the Windows 10 Scheduler - No Silver Bullet

[Presbytier]

It depends on whether we interpret the discussion of the "core/cache topology" to refer to that issue. Also fb, was actually just about to post that community update

So according to AMD it will take targeted optimizations, so maybe better in new games coming out, but don't expect to much improvement from released games.

 

[-PK-]

I read a nice discussion that the windows scheduler is not actually multi-thread aware. Multi-threading is handled by core parking under power management. Basically, when a thread is in use/parked on a core, it will unpark an idle core ready for use. I believe it then tests if this core is needed by splitting the thread to the unparked core and seeing if the cpu usage increases. This migration happens frequently. This means that windows will split threads and attempt to unpark about twice as many cores as there are full time threads. If a core affinity is set, once all affinity cores are in use/parked, it will ignore the affinity and unpark idle cores for use. I think core parking algorithm is numa (Non-Uniform Memory Access) aware when the cpu identifier identifies itself as such. It could still have a couple issues and not be a windows scheduler problem.

 

[zalazin]

another over hyped AMD product......

 

[Presbytier]

I read a nice discussion that the windows scheduler is not actually multi-thread aware. Multi-threading is handled by core parking under power management. Basically, when a thread is in use/parked on a core, it will unpark an idle core ready for use. I believe it then tests if this core is needed by splitting the thread to the unparked core and seeing if the cpu usage increases. This migration happens frequently. This means that windows will split threads and attempt to unpark about twice as many cores as there are full time threads. If a core affinity is set, once all affinity cores are in use/parked, it will ignore the affinity and unpark idle cores for use. I think core parking algorithm is numa (Non-Uniform Memory Access) aware when the cpu identifier identifies itself as such. It could still have a couple issues and not be a windows scheduler problem.

All you have to do is change windows power settings to max and it won't park cores

 

[tybert7]

So it looks like when you cross a cluster of 4 processors for a task, there's some sort of cache thrash going on here. (The 144 ns latency is likely the result of cache cleanups as it crosses the fabric...which you can think of as a highway going from one large city to another) This was a similar problem when vista was running scheduling which they fixed in windows 7. Threads getting thrown across processors each swap-in caused large penalties. However this is the result of trying to access a similar block of memory across cores. (Such situations include mutexes, context locks, and thread locks)

Am I interpreting this correctly?

It's interesting they are worried about Naples. If it's a server and the data is largely static, then cache thrash from concurrent access should be a minimum. (No concurrent db access row locks in read only mode)

This video was far more useful in highlighting what is going on, even if some of his logical core terminology might be a bit off.



There is a performance hit when you are using multiple cores across ccx's for some computation task. That probably needs to be fixed up in the game engine. If it can be done via some windows update, even better.

 

[ManofGod]

AMD posted this update in their community site today stating that they don't believe their is any scheduler issue in Windows 10.

It seems to ignore the issue with cross cluster communication demonstrated by PCPer.

Now I understand why my 1700x seems to be running 20C higher than my 1700, it is not! They add 20C, for some reason that I do not entirely understand, on top of the correct temp in the 1700x and 1800x. The 1700 has real temp readings but, the bios of my mainboard needs to be fixed to read the 1700x real temps instead. Otherwise, the fans run higher sooner than they need too.

 

[Presbytier]

Now I understand why my 1700x seems to be running 20C higher than my 1700, it is not! They add 20C, for some reason that I do not entirely understand, on top of the correct temp in the 1700x and 1800x. The 1700 has real temp readings but, the bios of my mainboard needs to be fixed to read the 1700x real temps instead. Otherwise, the fans run higher sooner than they need too.

yeah i could not figure out what they where saying about temps either but it is clearly a bios bug.

 

[-PK-]

All you have to do is change windows power settings to max and it won't park cores

True. The high performance power profile will set the cpu to always run at it's maximum clock and disables the XFR single core boost as well.

 

[allenpan]

wasnt it few years back AMD has same excuse? can someone refresh my memory? i think was one of the Quad or Octa-Core APU that has windows scheduler issues as well?

 

[Deleted whining member 223597]

wasnt it few years back AMD has same excuse? can someone refresh my memory? i think was one of the Quad or Octa-Core APU that has windows scheduler issues as well?

That was bulldozer, and that still hasn't changed to this day. The 2500K still destroys it in most games with the 2600K just walking away with it. Their GPUs have the same excuse, "wait for DX12". With AMD you always seem to have to wait to get all the performance promised.

 

[trparky]

another over hyped AMD product......

Then again, for those like me that are heavy multi-taskers that push our machines to the edge of the proverbial edge... AMD Ryzen is an excellent chip.

 

[Allynm]

If anything, the article brings good news for a 4-core Ryzen:

But there are some other important differences standing out here. Pings within the same physical core come out to 26 ns, and pings to adjacent physical cores are in the 42 ns range (lower than Intel, which is good), but that is not the whole story. Ryzen subdivides by what is called a "Core Complex", or CCX for short. Each CCX contains four physical Zen cores and they communicate through what AMD calls Infinity Fabric. That piece of information should click with the above chart, as it appears hopping across CCX's costs another 100 ns of latency, bringing the total to 142 ns for those cases.

That only means the core to core pings of a Ryzen quad core will beat those of an 8 core 5960X. I don't have complete figures to post here, but quad core Intel parts will also have pings on par with a single AMD CCX (quad core).

 

[DeathFromBelow]

That was bulldozer, and that still hasn't changed to this day. The 2500K still destroys it in most games with the 2600K just walking away with it. Their GPUs have the same excuse, "wait for DX12". With AMD you always seem to have to wait to get all the performance promised.

What is with these nasty Intel troll posts? Yes, the FX chips had a lot of cores with poor IPC. For less than the cost of an i5 you got a chip that was 'good enough' for 1080p gaming (especially if overclocked to the 4.2+ GHz range) and i7-level performance on multithreaded workloads. They can still keep up with the i7's in well-optimized games like Doom 2016. Mainboards using the 990FX chipset and it's derivatives were a lot cheaper and had more features (like 6x SATA 6GBs) than Intel did at the time, too. I'm still running an FX-8320 @ 4.8 GHz on a Gigabyte 990FX-UD3 in one box today.

Now with Ryzen we have what they originally set out to do: lots of cores with near-Intel IPC. These chips are a tremendous value.

 

[ChadD]

That was bulldozer, and that still hasn't changed to this day. The 2500K still destroys it in most games with the 2600K just walking away with it. Their GPUs have the same excuse, "wait for DX12". With AMD you always seem to have to wait to get all the performance promised.

What is with these nasty Intel troll posts? Yes, the FX chips had a lot of cores with poor IPC. For less than the cost of an i5 you got a chip that was 'good enough' for 1080p gaming (especially if overclocked to the 4.2+ GHz range) and i7-level performance on multithreaded workloads. They can still keep up with the i7's in well-optimized games like Doom 2016. Mainboards using the 990FX chipset and it's derivatives were a lot cheaper and had more features (like 6x SATA 6GBs) than Intel did at the time, too. I'm still running an FX-8320 @ 4.8 GHz on a Gigabyte 990FX-UD3 in one box today.

Now with Ryzen we have what they originally set out to do: lots of cores with near-Intel IPC. These chips are a tremendous value.

They are upset that Intel seems to be in a bit of trouble for the first time in a long time. They are about to suffer the same sort of fall poor MS has been in the midst of for the last few years.

AMD with Ryzen attacking their consumer base.
AMD shortly with Naples attacking their performance server base.
Qualcomm now with Centriq about to decimate in the massive data center server market.

If all that isn't scary enough for Intel and their investors... Qualcomm has partnered with the Chinese Gov in Huaxintong Semiconductor Technology. China is now no longer buying high end Intel chips for their servers, and likely they will stop buying their chips for a great number of other products shortly. AMD has also partnered with China to make x86 chips... and the Chinese are even making their own PowerPC chips, China wants away from Intel. That has to worry them, unless they are completely asleep.

Intel laid off nearly 20% of their workforce last year and lost a lot of high end talent. Its a very good time to cash in any Intel stock you may be holding on to. They won't go bust or anything just as MS hasn't, the good ole days of owning 90% (99% if you believe Intels numbers) of the market are likely over in the developed world. In the developing world their seems to be a real push by the Chinese Gov to rid themselves of American CPUs. There must be some great stories behind the scenes. Intel threatening to build Fabs in the US then backing off then restarting ect... there is more going on.

 

[ZeroBarrier]

They are upset that Intel seems to be in a bit of trouble for the first time in a long time. They are about to suffer the same sort of fall poor MS has been in the midst of for the last few years.

AMD with Ryzen attacking their consumer base.
AMD shortly with Naples attacking their performance server base.
Qualcomm now with Centriq about to decimate in the massive data center server market.

If all that isn't scary enough for Intel and their investors... Qualcomm has partnered with the Chinese Gov in Huaxintong Semiconductor Technology. China is now no longer buying high end Intel chips for their servers, and likely they will stop buying their chips for a great number of other products shortly. AMD has also partnered with China to make x86 chips... and the Chinese are even making their own PowerPC chips, China wants away from Intel. That has to worry them, unless they are completely asleep.

Intel laid off nearly 20% of their workforce last year and lost a lot of high end talent. Its a very good time to cash in any Intel stock you may be holding on to. They won't go bust or anything just as MS hasn't, the good ole days of owning 90% (99% if you believe Intels numbers) of the market are likely over in the developed world. In the developing world their seems to be a real push by the Chinese Gov to rid themselves of American CPUs. There must be some great stories behind the scenes. Intel threatening to build Fabs in the US then backing off then restarting ect... there is more going on.

Your logic is very flawed. The PC desktop market is primarily propped up by gaming, which is a market that's just shy of $100 billion. Intel still reins supreme in this segment by quite a sizable margin. If you somehow think that Intel's sales in the mainstream will be affected by Ryzen by any noticeable margin, you are sadly mistaken.

Also, telling people to sell their Intel stock? Are you demented? Intel stock is actually undervalued ATM and smart investors will be buying stock, not selling. They reported record $16.4 billion in sales last quarter and $59.4 billion in annual revenue of which $32.9 billion was client computing sales (up 2%); those are not numbers to sneeze at.

 

[Deleted whining member 223597]

What is with these nasty Intel troll posts? Yes, the FX chips had a lot of cores with poor IPC. For less than the cost of an i5 you got a chip that was 'good enough' for 1080p gaming (especially if overclocked to the 4.2+ GHz range) and i7-level performance on multithreaded workloads. They can still keep up with the i7's in well-optimized games like Doom 2016. Mainboards using the 990FX chipset and it's derivatives were a lot cheaper and had more features (like 6x SATA 6GBs) than Intel did at the time, too. I'm still running an FX-8320 @ 4.8 GHz on a Gigabyte 990FX-UD3 in one box today.

Now with Ryzen we have what they originally set out to do: lots of cores with near-Intel IPC. These chips are a tremendous value.

When you have to start your post with "Intel troll" you've already lost, but I'll go ahead and ignore it for now. I didn't realize an i5 cost $500+? The 8150 launched at $245, the 8320 at $170. Let's not go around changing history again. If 'good enough' is 80% of most of Intel's performance in most games, then good for you. Oh and I'm glad it can keep up in a few games, except I don't only play Doom. I'm not sure why you are trying to make Bulldozer look any better than it really was. It might have performed better in X tasks, but then it performed horribly in Y tasks. Oh and let's not start on the amount of heat they dumped, it was basically as bad as my W3520 when I OC'ed that to 4ghz.

They are upset that Intel seems to be in a bit of trouble for the first time in a long time. They are about to suffer the same sort of fall poor MS has been in the midst of for the last few years.

AMD with Ryzen attacking their consumer base.
AMD shortly with Naples attacking their performance server base.
Qualcomm now with Centriq about to decimate in the massive data center server market.

If all that isn't scary enough for Intel and their investors... Qualcomm has partnered with the Chinese Gov in Huaxintong Semiconductor Technology. China is now no longer buying high end Intel chips for their servers, and likely they will stop buying their chips for a great number of other products shortly. AMD has also partnered with China to make x86 chips... and the Chinese are even making their own PowerPC chips, China wants away from Intel. That has to worry them, unless they are completely asleep.

Intel laid off nearly 20% of their workforce last year and lost a lot of high end talent. Its a very good time to cash in any Intel stock you may be holding on to. They won't go bust or anything just as MS hasn't, the good ole days of owning 90% (99% if you believe Intels numbers) of the market are likely over in the developed world. In the developing world their seems to be a real push by the Chinese Gov to rid themselves of American CPUs. There must be some great stories behind the scenes. Intel threatening to build Fabs in the US then backing off then restarting ect... there is more going on.

Holy speculation batman! You think I care if Intel gets rekt by AMD or vice versa? No, I don't give a shit which is better unlike some of you. I just don't go around sugar coating everything.

The whole thing on Intel vs AMD stock, just lol.

 

[DuronBurgerMan]

Your logic is very flawed. The PC desktop market is primarily propped up by gaming, which is a market that's just shy of $100 billion. Intel still reins supreme in this segment by quite a sizable margin. If you somehow think that Intel's sales in the mainstream will be affected by Ryzen by any noticeable margin, you are sadly mistaken.

Also, telling people to sell their Intel stock? Are you demented? Intel stock is actually undervalued ATM and smart investors will be buying stock, not selling. They reported record $16.4 billion in sales last quarter and $59.4 billion in annual revenue of which $32.9 billion was client computing sales (up 2%); those are not numbers to sneeze at.

Honestly, Intel has been kind of stupid in recent years. Maybe this is because AMD was putting out such sh*tty products, like Bulldozer. Or maybe Intel has bad leadership. Whatever. All I know is I have a 6 year old 2600k box, and neither Intel nor AMD gave me any incentive to upgrade it until *very* recently. And even then, partly because this box is dying now. It used to be I could upgrade every 2 or 3 years, and gain nearly double the performance. 6 years, and the best Intel can do is give me a 7700k that's *maybe* 50% faster, stock vs stock. And until Ryzen, AMD couldn't even *match* the 2600k.

I don't care to fanboy over either brand. As far as I'm concerned, they've both f'ed up, just in very different ways.

 

[ZeroBarrier]

Honestly, Intel has been kind of stupid in recent years. Maybe this is because AMD was putting out such sh*tty products, like Bulldozer. Or maybe Intel has bad leadership. Whatever. All I know is I have a 6 year old 2600k box, and neither Intel nor AMD gave me any incentive to upgrade it until *very* recently. And even then, partly because this box is dying now. It used to be I could upgrade every 2 or 3 years, and gain nearly double the performance. 6 years, and the best Intel can do is give me a 7700k that's *maybe* 50% faster, stock vs stock. And until Ryzen, AMD couldn't even *match* the 2600k.

I don't care to fanboy over either brand. As far as I'm concerned, they've both f'ed up, just in very different ways.

I fully agree with you, but the only difference in my opinion is that Intel had no incentive to push CPU tech forward hard enough with no competition and I do not blame them. If they had, AMD would likely not exist today and that would have been worse for everyone, including Intel.

We also have to remember that there will eventually be a barrier we won't be able to push through with passed/current CPU tech until something drastically different becomes known ad more common place such as quantum computing or any other technologies that are discovered down the road.

 

[kac77]

AMD posted this update in their community site today stating that they don't believe their is any scheduler issue in Windows 10.

It seems to ignore the issue with cross cluster communication demonstrated by PCPer.

That's lawyer speak through and through, Do you know how much crap would be started if Windows 7 was found to perform better? MS is trying to phase that OS out. AMD has a crap ton of business with MS. They aren't going to jeopardize that. Personally Windows 8/10 in particular brought with it all sorts of weird performance problems.

 

[ChadD]

Your logic is very flawed. The PC desktop market is primarily propped up by gaming, which is a market that's just shy of $100 billion. Intel still reins supreme in this segment by quite a sizable margin. If you somehow think that Intel's sales in the mainstream will be affected by Ryzen by any noticeable margin, you are sadly mistaken.

Also, telling people to sell their Intel stock? Are you demented? Intel stock is actually undervalued ATM and smart investors will be buying stock, not selling. They reported record $16.4 billion in sales last quarter and $59.4 billion in annual revenue of which $32.9 billion was client computing sales (up 2%); those are not numbers to sneeze at.

Holy speculation batman! You think I care if Intel gets rekt by AMD or vice versa? No, I don't give a shit which is better unlike some of you. I just don't go around sugar coating everything.

The whole thing on Intel vs AMD stock, just lol.

No AMD isn't going to factor much into Intels financial fortunes this year. I wouldn't be buying AMD stock either right now... although it may have been a good time to get in a few months back and out in the next quarter or two. lol

The real threat comes from Qualcomm and a host of Chinese firms that are no longer purchasing Intel product. The Chinese for the last number of years have been the major sales driver in that market. Intel was the vendor selling to Chinese companies like Tencent Alibaba and Baidu (the # 4 5 and 6th largest internet companies in the world). The last year or so every single one of them have announced plans as per their Gov to move to NON US made computing solutions. They have already started replacing their Intel powered systems with Chinese made ARM, Power, and even X86 (with AMD help) solutions. The worlds fastest Super Computer right now at 125 petaflops is the Sunway TaihuLight which runs on ShenWei SW26010 processors. China is going to beat the US to exaflop computing by about 4 years if current plans hold in both countries. The US Gov screwed Intel over in April 2015 when they decided Intel had to stop selling its chips to China for its super computers. The Result was the Chinese Gov increasing spending on their own semi conductor industry. (there current plan went from 10 billion to 150 Billion in response) China buys 145 billion a year in silicon... Chinas response to the US gov is very bad news for both Intel and Nvidia.

So will the Intel good times hit a wall this year ? Hard to say... they may still have 4 more quarters of reasonable steady performance. However half the worlds server market is about to move away from them for sure. That is a done deal, and has nothing to do with AMD. For the last 20 quarters running Intel has shown flat growth in the consumer sector, and growth in the server area has flat lined. They haven't dropped a ton... the market also hasn't grown for them. They have expanded everywhere they could. Now for the first time US and Euro costumers have actual options... at the same time China is about to largely cut Intel out of the picture. So I don't think I am to far off the mark. At some point that is going to start translating into actual year to year down ward numbers that Intel isn't going to be able to easily hide. They are likely going to have to eat into their own margins to attempt and maintain revenue numbers. Investors that don't understand what is happening are going to react when Intel is forced to go from 60% margin numbers to 52-55% to retain some large server wins. (revenue aside a lot of the large margin comes from the server side).

So I listed AMD sure... but the real issue for Intel is Qualcomm and the Chinese surge in Gov R&D. It was laughable 5 years ago when the Chinese started making serious homegrown CPU designs. I don't think anyone is laughing now that they have taken the #1 super computer spot by a LARGE margin. Tianhe-2 the previous Intel powered #1 hits 33 tflops... since the Sunway TaihuLight you read far fewer news articles about super computing (ok that is subjective but I swear the last 6 months I have read very little). Anyway ya AMD is an irritant sure... the CPU industry sifting to China though, ya that is happening and its not going to be good for Intel. At some point in the next few years major internet companies that American Citizens have actually heard of are going to be eyeing some of the impressive work being done in China... and they are going to buy in even if it comes from companies like Qualcomm instead of through more direct Chinese joint ventures or out of the Jiāngnán Computing Lab.

Not to sound completely insane... but China out manufactured the west and upended our economies. They now have their eyes set on doing the same to the semi conductor industry.