Monday, October 8th 2018

AMD Introduces Dynamic Local Mode for Threadripper: up to 47% Performance Gain

AMD has made a blog post describing an upcoming feature for their Threadripper processors called "Dynamic Local Mode", which should help a lot with gaming performance on AMD's latest flagship CPUs.
Threadripper uses four dies in a multi-chip package, of which only two have a direct access path to the memory modules. The other two dies have to rely on Infinity Fabric for all their memory accesses, which comes with a significant latency hit. Many compute-heavy applications can run their workloads in the CPU cache, or require only very little memory access; these are not affected. Other applications, especially games, spread their workload over multiple cores, some of which end up with higher memory latency than expected, which results in a suboptimal performance.

The concept of multiple processors having different memory access paths is called NUMA (Non-uniform memory access). While technically it is possible for software to detect the NUMA configuration and attach each thread to the ideal processor core, most applications are not NUMA aware and the adoption rate is very slow, probably due to the low number of systems using such a concept.
In ThreadRipper, using Ryzen Master, users are free to switch between "Local Memory Access" mode or "Distributed Memory Access" mode, with the latter being the default for ThreadRipper, resulting in highest compute application performance. Local Mode on the other hand is better suited to games, but switching between the modes requires a reboot, which is very inconvenient for users.

AMD's new "Dynamic Local Mode" seeks to abolish that requirement by introducing a background process that continually monitors all running applications for their CPU usage and pushes the more busy ones onto the cores that have direct memory access, by adjusting their process affinity mask, which selects which processors the application is allowed to be scheduled on. Applications that require very little CPU are in turn pushed onto the cores with no memory access, because they are not so important for fast execution.
This update will be available starting October 29 in Ryzen Master, and will be automatically enabled unless the user manually chooses to disable it. AMD also plans to open the feature up to even more users by including Dynamic Local Mode as a default package in the AMD Chipset Drivers.
Source: AMD Blog Post
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86 Comments on AMD Introduces Dynamic Local Mode for Threadripper: up to 47% Performance Gain

#76
Nephilim666
Weird that someone would care about my post count or join date.
I am posting because I am a software engineer and had particular insight into why this couldn't be a driver solution.
My system specs are a Sandy Bridge and gtx980 not an AMD fanboy but since they're competitive for most things now I'm interested since I also prefer their business ethics.
Sorry for disturbing your chest-beating, I'll go back to lurking
Posted on Reply
#77
qubit
Overclocked quantum bit
Nephilim666Sorry for disturbing your chest-beating, I'll go back to lurking
No man don't do that! I for one appreciated your insight. :)
Posted on Reply
#78
jigar2speed
qubitAMD is still, what, 10% slower on IPC? That's still a win for Intel. Also, notice that I said Intel would win, not by how much. That depends on specific cases which is outside the scope of my comment.
Who told you AMD is 10% slower on IPC compared to Intel ? Got any link ?
Posted on Reply
#79
qubit
Overclocked quantum bit
jigar2speedWho told you AMD is 10% slower on IPC compared to Intel ? Got any link ?
I took that off the top of my head. You can tell by the way I've written it. Do you know what the exact difference is?
Posted on Reply
#80
jigar2speed
qubitI took that off the top of my head. You can tell by the way I've written it. Do you know what the exact difference is?
Below is the chart with IPC results via Guru3d

Posted on Reply
#81
qubit
Overclocked quantum bit
@jigar2speed That's quite close really, much more than I'd have expected, which is great to see. No wonder it's unsettling Intel.

By the looks of it, IPC performance has been isolated by locking all the CPUs at 3.5GHz. I think it will be interesting to see how well the 2700X does against its upcoming competition, the 9900K.

Have you got a link to the article, for the full picture?

Of course, when buying a product, what ultimately matters is how it performs at stock settings compared to the competition, along with the price. Overclocking matters too, but less so, as it's not a guaranteed result and much fewer people overclock.
Posted on Reply
#82
jigar2speed
qubit@jigar2speed That's quite close really, much more than I'd have expected, which is great to see. No wonder it's unsettling Intel.

By the looks of it, IPC performance has been isolated by locking all the CPUs at 3.5GHz. I think it will be interesting to see how well the 2700X does against its upcoming competition, the 9900K.

Have you got a link to the article, for the full picture?

Of course, when buying a product, what ultimately matters is how it performs at stock settings compared to the competition, along with the price. Overclocking matters too, but less so, as it's not a guaranteed result and much fewer people overclock.
I agree overclocking matters and Intel wins big time in that department.

Link to article - www.guru3d.com/articles_pages/amd_ryzen_threadripper_2950x_review,10.html
Posted on Reply
#83
qubit
Overclocked quantum bit
jigar2speedI agree overclocking matters and Intel wins big time in that department.

Link to article - www.guru3d.com/articles_pages/amd_ryzen_threadripper_2950x_review,10.html
Check out the 2600K in some of the gaming benchmarks - it's bottom fo the pile by some margin, lol. I've got the 2700K, so it pretty much performs the same. I really need to upgrade and I've noticed how it can't hit those really high framerates in modern games lol. If I can get the 9900K it will probably be a full twice as fast.
Posted on Reply
#84
EasyListening
gorillacookiesSaying, "Jim Keller is a Genius." might be an understatement.
Keller's over at Intel these days, chopping it up with Koduri. Imagine what those two are going to do with nigh-unlimited resources courtesy of Daddy Chipzilla... brings a smile to my face...
Posted on Reply
#85
bug
EasyListeningKeller's over at Intel these days, chopping it up with Koduri. Imagine what those two are going to do with nigh-unlimited resources courtesy of Daddy Chipzilla... brings a smile to my face...
Is Raja on the same level with Jim? I mean, where Jim built Zen, Raja built Vega?
Posted on Reply
#86
EasyListening
bugIs Raja on the same level with Jim? I mean, where Jim built Zen, Raja built Vega?
Raja was S3, ATI, Apple, AMD, and now Intel. Koduri, Keller, and Papermaster were together for iPhone3-4. Intel dropped it's entire iGPU program into Raja's lap, and there probably is noone else in the world who you could entrust more with the kind of insane task Intel is asking of him: please make our iGPU not suck. Raja's opening act was to throw their silicon out and replace it with AMD tech.
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