Investigating Performance of Multi-Threading on Zen 3 and AMD Ryzen 5000

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• Holliday75 - Thursday, December 3, 2020 - link

  As usage for modern users changes I wonder how this could be better tested/visualized.
  
  I am not looking at a 5900x to run any advanced tools. I am looking to game, run mutiple browsers with a few dozen tabs open, stream, download, run Plex (transcoding), security tools, VPN, and the million other applications a normal user would have running at any given point in time. While no two users will have the same workload at any given time, how could we quantify SMT versus no SMT for the average user?
  
  In the not to distance future we could be seeing the average PC running 32 cores. I am talking your run of the mill office machine from Dell that costs $800. Or will we? Is there a point where it does not matter anymore?

• realbabilu - Thursday, December 3, 2020 - link

  Simple. At average user 4 core 8gen u series have more core than the generation before. It has more strength, but it's rarely got 100 percent cpu utilized for those normal you doing.
  To get 8 threads or 4 cores work 100 percent need killer applications that programmed by man know how to extract every juice of it processor, know how to program multithread, or using optimized math kernel.library / optimized compiler switch like FEM, Render, math applied science.
  Other than those app, maybe you could expense it to gpu for gaming.

• schujj07 - Thursday, December 3, 2020 - link

  Or you just have multiple tabs open. I regularly hit 100% usage on my work i5-6400 with 4c/4t having 10-12 tabs open. It gets quite annoying as on a normal day I might need up to double that open at any given time. That means that 20 tabs would peg a 4c/8t CPU pretty easily.

• evilpaul666 - Friday, December 4, 2020 - link

  You need an ad blocker unless those tabs are all very busy doing something. I mean, it sounds like they're mining Monero for somebody else, I mean what they're *supposed* to be doing for you.

• schujj07 - Friday, December 4, 2020 - link

  I use an ad blocker and nothing is being mined. However, ads are an example of things that will destroy your performance in web browsing quite quickly and suck up a lot of CPU cycles. While right now 4c/8t is enough for an office machine, it will not be long before 6c/12t is the standard.

• marrakech - Tuesday, December 15, 2020 - link

  15 cores are the futureeeeee

• Hulk - Thursday, December 3, 2020 - link

  Wouldn't high SMT performance be an indication of bad software design rather than bad core design?
  While SMT performance is changing in these tests the core is not. Only the software is changing. It seems as though an Intel CPU in this comparison would have provided additional insights to these questions.

• BillyONeal - Thursday, December 3, 2020 - link

  The situations that create high SMT performance are generally outside the software in question's control. For example, a program might have 1 thread that's doing all divides and another that's doing all multiplies. The thread that only has multiplies or divisions aren't poorly designed, they just aren't using units on the chip that don't help their respective workloads.
  
  There are also cache effects. If you have 2 threads working on data bigger than the CPU's caches while one is waiting for that data to come back from memory the other can make unrelated progress and vice versa, but the data being big isn't necessarily an indicator of poor software design. Some problem domains just have big data sets there's no way around.

• WaltC - Thursday, December 3, 2020 - link

  Exactly. Some software is written to utilize a lot of threads simultaneously, some is not. Running software that does not make use of a lot of simultaneous threads tells us really nothing much about SMT CPU hardware, imo, other than "this software doesn't support it very well."

• Elstar - Thursday, December 3, 2020 - link

  SMT24? Ha. Try SMT128: https://en.wikipedia.org/wiki/Cray_XMT#Threadstorm...