Linus Torvalds: Too many cores = too much BS

[ninaholic37]

The future is tons of cores. I mean if I were to predict the CPU's in 10 years I'd say its 64+ cores.

2020 is probably where we reach 16 cores and 2025 where we reach 64+ cores

That will drive Linus mad... he will probably become Amish. :awe:

 

[TheELF]

The future is tons of cores. I mean if I were to predict the CPU's in 10 years I'd say its 64+ cores.

2020 is probably where we reach 16 cores and 2025 where we reach 64+ cores.

2030 I expect quantum computers to be available on a wider market, I think 2025 we see quantum computer breakthroughs and being used in big servers and supercomputers and 2030 reaching a more mainstream audience.

http://forums.anandtech.com/showthread.php?t=1042338
Sure this will happen,just like we got 10Ghz cpu's...
More than 4 cores is stupid for main stream since you have to make them slower/smaller to fit into the die/TDP.

 

[Ramses]

Nobody said that,what people said was that more cores don't give the end user any benefits if single core doesn't get a boost too.
It got so painfully obvious with the new haswell-e cpu's,
http://www.techspot.com/review/875-intel-core-i7-5960x-haswell-e/page8.html
if a programm has to synchronize it's threads than speed depends on single core speed.
http://www.legitreviews.com/powercolor-radeon-r7-250x-1gb-video-card-review_137172/5
It's the same story with all the games in this review(and any other that shows threads) one thread reaches the limit and thous limits all other threads.

I'm open to the idea that I'm just not getting something, but that seems to be the same as saying fewer, faster cores are preferable.

Am I correct in saying that past a certain core/thread count, it's a point of diminishing returns on the desktop because of the effort required to program for it? Maybe four or six?

Having gone from years ago when there were no multi core/HT cpu's, and software that took advantage of multiple CPU's was relatively rare, till now where 4 cores or more is common, there seems to be a real performance advantage with software/games that make an effort to use at least two or four of the available cores. It seems to stand out in games, there are several that are unashamedly single core games and run like crap unless you have a really fast single core for them to use. Then there's something like Crysis3 that I picked up the other day, it seems to put three to six cores to work and manage to run great even on my old FX chip which has notoriously crappy single core performance even before it was years old. I only half jokingly tell people the FX line has actually gotten better with age as more software seems to be able to spread itself across it. I only just checked it for a moment when I first ran it, but I swear I had more even CPU utilization than legitreviews was showing. My assumption was since the core count was rising on Intel CPU's and the performance per-core wasn't getting dramatically higher, developers were finding ways to make use of those cores. My understanding is that there is a penalty performance wise for doing so VS running on one or two very fast cores, but as I said it seems to be what we have to work with for the foreseeable future due to economics and chip manufacturers direction. I completely believe that past a certain core count on the desktop it's pointless, but as I used the selling TV 's analogy earlier, they have to come out with something to move new chips every year, other than a cute name and a new box.

edit: Crysis3 CPU usage.

 

[TheELF]

I'm open to the idea that I'm just not getting something, but that seems to be the same as saying fewer, faster cores are preferable.

No,faster AND more cores are preferable,but if you are on a budget you go for single core speed.

Because not having enough cores might slow down the main game loop below the maximum single core speed,but
if you have half the single core speed to begin with,because you have double(or more) the cores, then the main loop won't loose any speed but it will start at half the speed,
and that's why you often see an I3 being faster than 6-8 cores cpus

Yes if studios start adding needless things to games to bloat them up so more cores will be used than yeah the fast 2core CPU might slow down so much that it will start being slower than a slow 8 core, but looking at current-gen console this will take many years to happen if at all.

The Screenshots you posted might just show thread migration
http://superuser.com/questions/678666/windows-8-1-process-migration-limits-cpu-frequency-scaling

You need a program like process explorer that will show you the actual threads.

 

[Ramses]

Gotcha, I'll look into process explorer. Whatever they are doing seems to work though, after so much talk I expected c3 to run like crap on this thing.

 

[Spungo]

For all the talk about how important single threaded performance is, can anyone name some programs that are single thread CPU bottlenecked?
If you handed me a computer with a super fast SSD and tons of memory, I would have a very hard time telling you if it had a fast CPU or a slow CPU unless I was doing something like playing games, which is something most computer users don't do. Maybe one computer can open Windows Explorer 1 nanosecond faster than another, but I can't tell the difference.

With that in mind, the limitation seems to be how many things you can do at one time, and that's where multicore shines. More cores allows the computer to do more things at one time. One thread is making Windows look pretty, one thread is indexing your files in the background, one thread is checking if the system needs any updates, one thread is playing music, one thread is doing on the fly NTFS compression, one thread is checking drive consistency, and none of these things are affecting the CPU performance of the others. You couldn't really do that in the past. With just 1 or 2 cores, it quickly becomes a zero sum game.

 

[Ramses]

I remember being able to play quake II and listen to mp3's at the same time with one of my early smp systems. It was so awesome compared to any single cpu back then.

 

[SlickR12345]

http://forums.anandtech.com/showthread.php?t=1042338
Sure this will happen,just like we got 10Ghz cpu's...
More than 4 cores is stupid for main stream since you have to make them slower/smaller to fit into the die/TDP.

LOL. There are a ton of applications these days that use 12+ cores, most servers use 12+ cores individually, most server farms use thousands of processors each.

So this is nothing like the GHz hype, which is just the frequency. 64+ cores are going to be standard in 10 years, heck we may even see 128+ core processors.

I'm predicting 16+ cores as mainstream in 2020 and 64+ cores being mainstream in 2025.

 

[ShintaiDK]

LOL. There are a ton of applications these days that use 12+ cores, most servers use 12+ cores individually, most server farms use thousands of processors each.

So this is nothing like the GHz hype, which is just the frequency. 64+ cores are going to be standard in 10 years, heck we may even see 128+ core processors.

I'm predicting 16+ cores as mainstream in 2020 and 64+ cores being mainstream in 2025.

The problem is servers have an entirely different workload. Its concurrency/client-server. We already have server CPUs with 15 or more cores today. However for the mainstream the core count is much lower and that wont change this year either. While the server may get even more cores.

We need something completely revolutionizing on the software side for your prediction to happen. Or simply some kind of consolidation. 1 PC for an entire household that is shared. But I dont think that is what you hope for.

 

[TheELF]

LOL. There are a ton of applications these days that use 12+ cores, most servers use 12+ cores individually, most server farms use thousands of processors each.

Yes they do,but have you ever thought about what kind of workload they have?
Servers are real time systems, they have to reply to thousands of user requests in real time (or as fast as possible) ,in this case it makes sense to have a lot of weak cores since each request is just very simple stuff like a database query or similar which does not need any speed.

 

[TheELF]

With that in mind, the limitation seems to be how many things you can do at one time, and that's where multicore shines. More cores allows the computer to do more things at one time. One thread is making Windows look pretty, one thread is indexing your files in the background, one thread is checking if the system needs any updates, one thread is playing music, one thread is doing on the fly NTFS compression, one thread is checking drive consistency, and none of these things are affecting the CPU performance of the others. You couldn't really do that in the past. With just 1 or 2 cores, it quickly becomes a zero sum game.

All the system threads(and most others too) do nothing most of the time and when they do anything it's such a small percentage of CPU resources that they almost don't count at all.
Lookie here most of them are <0.001 cpu usage.
Look at the bottom of the pic for total thread count and CPU usage,it's ridiculous the amount of threads you can run on a lowly dual core,it's only when you run a number of programs that actually need some grunt where multicore becomes an issue.
Like you said "most computer users don't play games" well most computer users also don't run a lot of heavy stuff at once.

 

[ashetos]

On a 3.3GHz quad core Sandy bridge and Windows 7 64-bit:
- one windows media player window playing mp3
- two firefox tabs, wikipedia(light) + gosugamers(javascript+flash)
- one antivirus scan on system partition (on OCZ Vertex 4)

Task manager->CPU usage 60%

That is, freaking 60%:
-without skype
-without dropbox
-without MS Office
-without any video game
-without thunderbird
-without any Adobe programme
-without any CAD programme
-without some project compilation
-without video playback
-without audio or video processing
-without any backup/sync programme
-without any defragmentation taking place
-without any VMs
-without any emulators
-without windows updates running
-without any program updates/installation running
-without any servers
...

The list goes on...

Do you find that 4 cores are enough for high-end mainstream desktop PCs in 2015? Intel Core 2 Quad was sub-300$ in 2007 already! Some of you people have very low standards for processors.

I can't believe that the desktop segment with a thermal/power budget of 140 Watts per socket uses the same chips that are used at 40 Watts TDP in laptops. Why must we compromise?

 

[ShintaiDK]

Your AV takes what, 40% or more? And its done in what, 2-5mins? With what, weeks till next scan?

Yes 4 cores is plenty.

 

[ashetos]

Yeah, let's just use two firefox tabs and call it a day. Who needs to do more with a desktop computer?

But wait! Even that experience was DESTROYED by an antivirus scan. Now my firefox tab is all choppy.

Next time, I'll wait for the scan to finish, and THEN I'll open the browser.

No, 4 cores are not enough.

See, I copied your style.

 

[ninaholic37]

For all the talk about how important single threaded performance is, can anyone name some programs that are single thread CPU bottlenecked?

Dosbox.

On my Atom N2600 (2C/4T), I could only get about 11000 cycles before it hits the 25% CPU limit (100% on one core). My guess is that someone with a Bay Trail might be able to get 15000, and that no "small-core" can get over 20000. This runs many games very poorly, 6-8fps and choppy as ****. For a completely smooth experience in some games (around 125000 cycles), you pretty much need an i5-4690k, or at least something that isn't Atom or Jaguar based.

 

[Enigmoid]

On a 3.3GHz quad core Sandy bridge and Windows 7 64-bit:
- one windows media player window playing mp3
- two firefox tabs, wikipedia(light) + gosugamers(javascript+flash)
- one antivirus scan on system partition (on OCZ Vertex 4)

Task manager->CPU usage 60%

That is, freaking 60%:
-without skype
-without dropbox
-without MS Office
-without any video game
-without thunderbird
-without any Adobe programme
-without any CAD programme
-without some project compilation
-without video playback
-without audio or video processing
-without any backup/sync programme
-without any defragmentation taking place
-without any VMs
-without any emulators
-without windows updates running
-without any program updates/installation running
-without any servers
...

The list goes on...

Do you find that 4 cores are enough for high-end mainstream desktop PCs in 2015? Intel Core 2 Quad was sub-300$ in 2007 already! Some of you people have very low standards for processors.

I can't believe that the desktop segment with a thermal/power budget of 140 Watts per socket uses the same chips that are used at 40 Watts TDP in laptops. Why must we compromise?

That is using the bulk of the CPU.

Don't kid yourself. How is one person supposed to do that much stuff at once?

Here is an example of your senario. I have specifically ignored things that would use 100% CPU (rendering, transcoding, etc) because they chew up all CPU resources and thus no matter how many cores you have the experience of doing multiple things is poor.

On a 3.2 ghz 3630qm. 8 GB RAM (which IMO is the limit for these tasks, not the CPU).

Active
-itunes music
-720p VLC movie
-virus scan
-torrent
-4K youtube video

Other
-10 chrome tabs
-5 firefox tabs
-Mathematica 8
-Maple 16
-Codeblocks
-PDF
-DJVU file
-Kindle
-Calibre ebook
-3dsmax
-maya
-Origin
-Photoshop
-Paint

Unless I'm running something like rendering/transcoding/compiling I really do not need more CPU (35-60% usage). I need more RAM.

Not to mention the utter insanity of what I have going on (3 audio streams).

 

[III-V]

The future is tons of cores. I mean if I were to predict the CPU's in 10 years I'd say its 64+ cores.

2020 is probably where we reach 16 cores and 2025 where we reach 64+ cores.

2030 I expect quantum computers to be available on a wider market, I think 2025 we see quantum computer breakthroughs and being used in big servers and supercomputers and 2030 reaching a more mainstream audience.

I'd be highly surprised if anything more than 8 were mainstream in 10 years. You need to realize that, at most, that'd be 5 nodes. You think they're going to spend those nodes doubling core counts just about every time?

Unless you're talking about server/HEDT. That's certainly feasible... but I think you're pushing it for HEDT.

 

[TheRyuu]

Servers are real time systems, they have to reply to thousands of user requests in real time (or as fast as possible)

I'm not sure your definition of "real time system" is the same as everybody else's. Servers are about the farthest thing from a real time system. Even your desktop doesn't really qualify as a real time system although is does favor latency over throughput.

Server's care about macro latency (throughput, e.g. no preemption, 100hz kernel tick) while desktop's want micro latency, which is why your desktop OS probably uses hardware preemption.

 

[Ramses]

So no matter how we or Linus or anyone else feels about it, unless Intel and co can find a way to make dramatically faster cores cheaply, cool-running-ly, soon, we're stuck with lots of cores and marginal gains here and there? If it's trickle down from Server CPU developement (more income?) it's even more likely.

I would think the best way to prompt them to do otherwise would for software to require fewer, faster cores to run acceptably and consumers to buy or not buy accordingly. We seem to be at a point where the hardware is ahead of the software though with the number of people happy with relatively old gear.

And at the risk or wearing a conspiracy hat, I'm not convinced they aren't dragging things out on purpose because there just isn't anywhere else to go that's sellable to the average user or enthusiast. 4 core 8+ghz cpu can happen and be amazing pretty soon for enough money, but nobody will buy it if it costs $2-3K a pop right? They will buy next years $300 6 core or the year afters $300 8 core, etc, etc. And they aren't bad, but nor are they leading us into a brave new world of CPU performance either that I can see. It's going to, and is, taking a lot of the wind out of the sails of this as a fun and interesting hobby not having steady upward progress. It's already dramatically slower going than it was not too many years ago. I wish someone would do something interesting, even if it is expensive. Software, hardware, whatever.

 

[Ramses]

You need a program like process explorer that will show you the actual threads.

Ran process explorer, I've actually used it before but it's been a long time. It seems to mirror what I was seeing in Task Manager, lists 70 "threads" for C3, and I'm yet to find a way to track what thread is running on what core. Some google'ing says easier said than done but I'll look further into it.

 

[Cerb]

And at the risk or wearing a conspiracy hat, I'm not convinced they aren't dragging things out on purpose because there just isn't anywhere else to go that's sellable to the average user or enthusiast. 4 core 8+ghz cpu can happen and be amazing pretty soon for enough money, but nobody will buy it if it costs $2-3K a pop right?

That's far from tin foil hat. It has to sell to be able to be offered at a reasonable price. IE, the MSRP (or other OEM-specific prices) are based on recouping costs of development, plus manufacture, plus support, plus profits on top of that. Almost nobody wants to buy a 150W+ CPU. I don't doubt, given OCs, and general process improvements, Intel couldn't tweak their cores and processes to reach such speeds, over a few generations. But, if that would take away from their performance at lower speeds and power envelopes, it would not be worth doing, and it surely would take that.

While we see little each gen on our gaming desktops, corporate and gaming notebooks with Haswell are much superior to IB, due to all the power efficiency built in, and while pretty much saturated, it's not exactly a small market. A full sized notebook w/ IGP can, without a humongous battery, get a light work day of use from a full charge in the morning. Until then, the best I ever saw doing that were Fujitsus with slow ULV chips, crappy screens, and souped up 3rd-party batteries. There's a lot of overlap across what they need to do to make fat cores work on tablets, make them work better on notebooks, and make them work better in servers. The small amount of people that want super fast CPUs that eat a lot of power are just too small to drive the R&D to make it happen. If it wouldn't take compromises on the mobile and server CPUs to do it, they would offer them, just at a premium cost (it's not like that would be a new behavior for either Intel or AMD).

 

[Ramses]

Good point on the laptops. I bought one, actually two, recently and was pretty impressed by the speed and lack of heat and power usage. One was actually an amd a8-6410 (i think) and the one I settled on is an i7-4510u with an 840M GPU. Nothing high end either really, but they were both plenty for daily use given an SSD and enough RAM. Far cry from what they used to be.

 

[TheELF]

Ran process explorer, I've actually used it before but it's been a long time. It seems to mirror what I was seeing in Task Manager, lists 70 "threads" for C3, and I'm yet to find a way to track what thread is running on what core. Some google'ing says easier said than done but I'll look further into it.

You can't find out which thread runs where since windows juggles them around as it sees fit.
What you can see is how much CPU power every single thread needs,by double clicking and then going to the threads tab,this for example could show up as all cores at 50% for a dual or all cores at 25% for a quad, just because they they don't run the same thread on the same core all the time.

 

[Ramses]

I see, will check. Shame one can't tell how threaded a given program is, there's a lot of talk about such these days. Is everyone just looking at task manager and making an educated guess?

 

[SlickR12345]

I'd be highly surprised if anything more than 8 were mainstream in 10 years. You need to realize that, at most, that'd be 5 nodes. You think they're going to spend those nodes doubling core counts just about every time?

Unless you're talking about server/HEDT. That's certainly feasible... but I think you're pushing it for HEDT.

Today is 2015 and the mainstream is 4 cores, you don't think that in 5 years time we would have 16 cores?

And in 10 years time there are enough innovations in the pipeline that even if half made it through we are going to see huge numbers of cores. Doesn't mean its going to be the same type cores as today.