CPU
and a short introduction do processors
GPU
vs
WHY a GPU ?
The initial idea of GPUs was to share the load of the main processor
GPUs evolved to excel on the repetitive and block tasks
GPGPU
General-purpose computing on graphics processing units
GPU
CPU
9.6 x faster !
CPUs and GPUs work basically the same way, using different architectures
But How does a CPU WORKs ?
a really quick introduction
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90
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1 1 1 1 1 1 1 1 → 255
8 bit
0 → 0
1 → 1
10 → 2
11 → 3
100 → 4
101 → 5
8bit → 2⁸ → 256
9bit → 2⁹ → 512
10bit → 2¹⁰ → 1024
16bit → 2¹⁶ → 65536
32bit → 2³² → 4294967296
64bit → 2⁶⁴ → 9223372036854775808
The transistor
AND GATE
OR GATE
addition
0
1
0
0
+
0
1
0
1
0
1
+
1
0
Half adder
The half adder adds two single binary digits A and B. It has two outputs, sum (S) and carry (C).
| A | B | C | S | |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | |
| 0 | 1 | 0 | 1 | |
| 1 | 0 | 0 | 1 | |
| 1 | 1 | 1 | 0 |
Full adder
Memory
Reading
10011
Reading
CPU
10011
Reading
CPU
10011
01001
Reading
CPU
Writing
00101
Writing
CPU
00101
11010
Writing
CPU
00101
11010
Writing
CPU
Data on RAM
- Values (numbers, letters etc)
- Addresses (RAM or devices)
- Instructions (load, add, store, jump etc)
Inside the CPU
A
B
inputs
A
B
inputs
RAM
instruction
type of
operation
A
B
inputs
RAM
instruction
type of
operation
A
B
inputs
RAM
instruction
type of
operation
flags
A
B
inputs
RAM
instruction
type of
operation
flags
Instructions & ARCHITECTURES
Regardless of manufacturer or model, processors need to be able to understand the same set of instructions
architectures
micro-architecture - x86
x86
x86-64
ARM
SIMD
Instruction sets - x86
So, What's the difference between CPU and GPU ?
Instruction sets aren't exactly the same. GPUs evolved for graphics and they have, for example, clear instructions for repetitive matrices operations.
CPUs, on the other hand, are able to better handle more complex sets of instructions, using bigger registers and RAM
CONTROL UNIT
ALU
REGISTER & CACHE
CPU
GPU
nVidia Tesla M40
CPU CHART
GPU
GTX 1080
CPU
intel i7
thanks for your attention !
CPUs vs GPUs
By Felipe Delestro
