19
votes
Accepted
Is it true that on a modern processor, parallelism is possible on a single core?
It is indeed possible to have parallelism on a superscalar processor. A superscalar processor can execute multiple instructions at the same time by using multiple execution units.
There are certain ...
- 6,177
16
votes
Why do modern processors use few advanced cores instead of many simple ones or some hybrid combination of the two?
Programming for parallelism is difficult, so most things are largely done sequentially which requires more complex processors. The clock limit prevents the processors from getting much more complex so ...
- 57k
15
votes
Why do modern processors use few advanced cores instead of many simple ones or some hybrid combination of the two?
From what I understand a GPU is an extreme version of this, but isn't there some middle ground for certain tasks that needs a density/complexity which is somewhere between the two extremes?
Modern ...
- 98.4k
11
votes
Is it true that on a modern processor, parallelism is possible on a single core?
There are lots of different types of parallelism.
Instruction level parallelism is a feature of any superscalar processor. Multiple instructions are in progress at any point in time. However, those ...
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10
votes
Is it true that on a modern processor, parallelism is possible on a single core?
On some processors this is (sometimes) possible. Since different instructions use different processor resources (ALU, floating point, load, store, etc), it's sometimes possible to parallelize some of ...
- 700
5
votes
Do multi-core processors reduce power consumption?
According to the video starting at 5:05 it's not, as you write
$$ P = P1 + P2 = 2 ( C V^2 f/2 ) $$
but
$$ P_{reduced} = 2.2 C ⋅ (0.6 V)^2 ⋅ f/2 $$
$$ = 2.2C ⋅ 0.36 V^2 ⋅ f/2 $$
$$ = (2.2 ⋅ 0.36 ⋅ 0.5) ...
- 174
4
votes
Accepted
On which core on a multi core CPU is the ISR called?
The answer is that the inbound Interrupt does not connect directly to any core in a multicore architecture (given your question asks about Intel and ARM).
For the Intel CPU architecture models (I don'...
- 21.9k
4
votes
Why do modern processors use few advanced cores instead of many simple ones or some hybrid combination of the two?
I'd like to take the frame challenge further than the other answers here. Until the end of the 20th Century, parallel computing was the domain of specialist servers and supercomputers; general-purpose ...
- 141
3
votes
Why do modern processors use few advanced cores instead of many simple ones or some hybrid combination of the two?
Umm, GPUs are not “an extreme version of a system with many simple cores”. Eg in an Nvidia GPU each SM (streaming multiprocessor) is a highly multithreaded processor. The data path is IIRC 16 lanes, ...
- 319
3
votes
Why do modern processors use few advanced cores instead of many simple ones or some hybrid combination of the two?
Some tasks lend themselves to parallelism, some don’t. Broadly, tasks that tend to be repetitive with lots of time spent in loops can be partitioned into smaller sub tasks, marshaled by the host. ...
- 56.1k
3
votes
CPU (core) all located in close proximity. A coincidence or by design?
I assume you're talking about a multi-core processor such as this one from Intel (source):
As is kind of evident from the picture, the CPU cores themselves have common logic that they all need access ...
- 161
3
votes
CPU (core) all located in close proximity. A coincidence or by design?
CPU cores have high trace count buses connecting them and their shared caches. They're physically arranged close to each other to keep those costly and power-hungry buses as short as possible. ...
- 17.8k
3
votes
Accepted
Multicore ARM how to assign a critical task to one dedicated core
I have worked with NXP LPC4300 series dual core ARM Cortex M chips.
You do not "assign" tasks as you do on a PC. The way you do this is to compile two separate projects, since both cores operate ...
- 23.6k
2
votes
Accepted
Multi-core processor and Real Time
It really depends on the application.
I think however what you are describing is a multi-threaded controller. Where programs are sequenced to one or more processors under the control of some ...
- 46.9k
2
votes
Multi-core processor and Real Time
When designing multitasking real-time systems, you assign each task a priority that allows it to meet its deadline, keeping in mind that it may be preempted by any higher-priority tasks. If you have N ...
- 177k
2
votes
Why do modern processors use few advanced cores instead of many simple ones or some hybrid combination of the two?
TL:DR: Yes, but not for most tasks. That's why the current iteration of this idea is hybrid CPUs with some performance, some efficiency cores, now that we have transistor budgets to throw that many ...
- 1,366
1
vote
Accepted
Multicore CPU design dilemma on reading from/writing to hardware devices
The problem you're describing is called "bus contention". I'm not going to pretend to be able to list all the possible solutions here, but two examples are bus arbitration and dual-port ...
- 46.7k
1
vote
Why disable interrupt is time-consuming in multi-processor computer?
[Note: I read your question too quickly when I started answering, and didn't notice that you specified "multi-processor system". I'm leaving in the first part, which is also relevant to single-...
- 2,294
1
vote
Accepted
multiprocessor programming and memory management
We had a course in college which we program multiprocessors.Here are some sources, which we use:
M.J. Quinn: Parallel programming in C with MPI and OpenMPI, Mc Graw Hill, Boston, 2003 Internet
N. ...
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Only top scored, non community-wiki answers of a minimum length are eligible