How many computers in here do you think we've got multiple processors in?
How many computers in here do you think we've got multiple processors in?

Ok, um, yeah, I don't think any of them have got multiple processors in the way that I would think of multiple processors
Ok, um, yeah, I don't think any of them have got multiple processors in the way that I would think of multiple processors

My edit machine has two Intel processors in it, physical chips
My edit machine has two Intel processors in it, physical chips

Ok, so you define a multiprocessor system as having two physical chips?
Ok, so you define a multiprocessor system as having two physical chips?

That's what I'm thinking.
That's what I'm thinking.

Okay, or we could also take multiple cores. Where it's the same thing on the same pieces of the silicon.
Okay, or we could also take multiple cores. Where it's the same thing on the same pieces of the silicon.

Okay, so you've got two physical chips being two physical processors which machine or multiple cores which machines in here do you think are multiprocessor?
Okay, so you've got two physical chips being two physical processors which machine or multiple cores which machines in here do you think are multiprocessor?

We'll just use that term to refer to both of them systems.
We'll just use that term to refer to both of them systems.

Okay. Well, I reckon these new Macs here have got multiple cores.
Okay. Well, I reckon these new Macs here have got multiple cores.

Yup, they're all quad core machines of various types
Yup, they're all quad core machines of various types

Your phone maybe? Yeah the phone will
Your phone maybe? Yeah the phone will

but you've got all these vintage machines around
but you've got all these vintage machines around

So starting over here with the apple macintosh LC 475. Well, let's just say I said, you've got one processor in it. There's also a
So starting over here with the apple macintosh LC 475. Well, let's just say I said, you've got one processor in it. There's also a

PowerPC laptop under there underneath the surface underneath the multi processor motherboard
PowerPC laptop under there underneath the surface underneath the multi processor motherboard

So the surface is real depressed is just sitting under there the Atari ST
So the surface is real depressed is just sitting under there the Atari ST

That one we could count this as we'll say it isn't why? Could we count it out?
That one we could count this as we'll say it isn't why? Could we count it out?

Because the keyboard has got a CPU in it. Okay. Yeah, I've got an intelligent keyboard. So the CPUs got a
Because the keyboard has got a CPU in it. Okay. Yeah, I've got an intelligent keyboard. So the CPUs got a

microcontroller in there which scans the keyboard and then sends over a serial link the key presses to
microcontroller in there which scans the keyboard and then sends over a serial link the key presses to

The main CPU and so on so so proprietor in there. I've got the Atari Falcon under here how many processors?
The main CPU and so on so so proprietor in there. I've got the Atari Falcon under here how many processors?

I'm guessing that there's a trick here. So I'm going for two. Yes got two processors in it. It's got a
I'm guessing that there's a trick here. So I'm going for two. Yes got two processors in it. It's got a

68030 cpu and it's also got a five six zero zero one DSP both motorola
68030 cpu and it's also got a five six zero zero one DSP both motorola

Processors in that don't think any of that acorn stuff which are now relatively. Well. Yep
Processors in that don't think any of that acorn stuff which are now relatively. Well. Yep

So they're all single processor systems. Although the risk PC did have two prices of slots
So they're all single processor systems. Although the risk PC did have two prices of slots

So it could have read a separate 486 put in there and let's say managed to get hold of the one existing Hydra card in
So it could have read a separate 486 put in there and let's say managed to get hold of the one existing Hydra card in

Enable you to have multiple ARM chip so that single processor their original IBM PC
Enable you to have multiple ARM chip so that single processor their original IBM PC

Single processor BBC micro I think if that's a special one then possibly but if just under one man, no
Single processor BBC micro I think if that's a special one then possibly but if just under one man, no

So that is a special one. That's actually got what a Concord they're tube system
So that is a special one. That's actually got what a Concord they're tube system

Which if you watch the videos on Steve Furber?
Which if you watch the videos on Steve Furber?

Talks more about this, but they initially released the second processor not Co prices over the second processor for the system
Talks more about this, but they initially released the second processor not Co prices over the second processor for the system

Which was a complete another computer inside there with a 6502 Ram and so on in their 64k of Ram
Which was a complete another computer inside there with a 6502 Ram and so on in their 64k of Ram

Showed that old it was and that was then connected to the BBC micro which had its
Showed that old it was and that was then connected to the BBC micro which had its

32k of RAM and its 6502 on there the master turbo
32k of RAM and its 6502 on there the master turbo

I've got over there has that built into the motherboard and so that's technically a multiprocessor system. It's got two CPUs in there
I've got over there has that built into the motherboard and so that's technically a multiprocessor system. It's got two CPUs in there

She's got two CPUs at the same time
She's got two CPUs at the same time

Running a slightly different speeds but to CPS at the same time Apple to single processor the acorn and the Amiga and the Atari
Running a slightly different speeds but to CPS at the same time Apple to single processor the acorn and the Amiga and the Atari

Again, the Amiga I think you could possibly make an argument. It was a multiprocessor system, but not in the way
Again, the Amiga I think you could possibly make an argument. It was a multiprocessor system, but not in the way

We're thinking about it. Why have we just done that? Well, it shows that there's there's two ways you can design a multiprocessor system
We're thinking about it. Why have we just done that? Well, it shows that there's there's two ways you can design a multiprocessor system

So your system home your editing system the Macs on here. They have two processes.
So your system home your editing system the Macs on here. They have two processes.

That are of the same design to Intel court or two core. Shall we say or
That are of the same design to Intel court or two core. Shall we say or

multiple cores all of the same design
multiple cores all of the same design

And those purchases are identical and they use pretty much to do any of the tasks of things
And those purchases are identical and they use pretty much to do any of the tasks of things

It's what we call a symmetric multiprocessor system
It's what we call a symmetric multiprocessor system

So each CPU in there can be allocated by the operating system to run programs
So each CPU in there can be allocated by the operating system to run programs

It can answer io and things and just do anything that you need to do. They can split the tasks up
It can answer io and things and just do anything that you need to do. They can split the tasks up

To do different things
To do different things

by comparison the Falcon and the
by comparison the Falcon and the

BBC micro system the BBC master turbo
BBC micro system the BBC master turbo

They have multiple processes in them and you can use them for general purpose tests
They have multiple processes in them and you can use them for general purpose tests

But the general idea is that their processes do different tasks. So it's an asymmetric multiprocessor system
But the general idea is that their processes do different tasks. So it's an asymmetric multiprocessor system

Say for example on the Falcon
Say for example on the Falcon

The idea was at the 68030
The idea was at the 68030

would run you the main system whatever thing is doing and then he fueled you to do some sort of person that would benefit from
would run you the main system whatever thing is doing and then he fueled you to do some sort of person that would benefit from

The DSP chip the five six zero zero one that's in there
The DSP chip the five six zero zero one that's in there

You would offload your processing onto that feed the data and it would president it would feed the data back out
You would offload your processing onto that feed the data and it would president it would feed the data back out

So it's effectively running as a separate
So it's effectively running as a separate

Subsystem and so on
Subsystem and so on

On the BBC micro system. The idea was since that you'd have the 6502 chip
On the BBC micro system. The idea was since that you'd have the 6502 chip

There's in there's normal running the IO
There's in there's normal running the IO

Drawing things on the screen handling the keyboard and so on and then you'd have your main processor
Drawing things on the screen handling the keyboard and so on and then you'd have your main processor

That would do most of the processing work and occasionally would tell the other processor
That would do most of the processing work and occasionally would tell the other processor

to load a file into memory or to tell the other processor to do things so you can design a
to load a file into memory or to tell the other processor to do things so you can design a

Multi-person system in two ways. You can either have it
Multi-person system in two ways. You can either have it

So all the CPUs are working on the same task and in that case
So all the CPUs are working on the same task and in that case

They probably will all connect to the same piece of shared memory and they'd all
They probably will all connect to the same piece of shared memory and they'd all

work on the same task and they'd all talk to the same bit memory and
work on the same task and they'd all talk to the same bit memory and

Communicate along that or you can say now I'm gonna have different processes perhaps of different types different speeds doing different jobs
Communicate along that or you can say now I'm gonna have different processes perhaps of different types different speeds doing different jobs

So multiprocessor systems have been around for quite a while in various different guises
So multiprocessor systems have been around for quite a while in various different guises

There's a sort of suggestion here that the idea of parallel is the more modern way of doing it surely with things like GPUs
There's a sort of suggestion here that the idea of parallel is the more modern way of doing it surely with things like GPUs

Coming we've got hybrids now, right? Well, yeah. Well, yeah, but I mean the GPU is generally being used for a specific task
Coming we've got hybrids now, right? Well, yeah. Well, yeah, but I mean the GPU is generally being used for a specific task

things whether that's graphics processing or Bitcoin mining or whatever it is able to do on it and depending on whether you're wanting to make
things whether that's graphics processing or Bitcoin mining or whatever it is able to do on it and depending on whether you're wanting to make

Money or lose money and I can let you work out which one of that is going to do which and surely we're using
Money or lose money and I can let you work out which one of that is going to do which and surely we're using

Multiple cores purely because we ran out of horsepower on single cores
Multiple cores purely because we ran out of horsepower on single cores

So one reason with 4 cores good question
So one reason with 4 cores good question

So the things you want to fight the problem run as fast as possible and you've got two ways to do that
So the things you want to fight the problem run as fast as possible and you've got two ways to do that

You can either make the computer run faster
You can either make the computer run faster

for example, speak fast you get more words per second and so on and you get it going and you get your computer doing more and more and
for example, speak fast you get more words per second and so on and you get it going and you get your computer doing more and more and

More more and more more more more more more more faster and faster faster faster and faster, the problem with
More more and more more more more more more more faster and faster faster faster and faster, the problem with

Is that is you get to a point where you can't actually push the computer faster. There's a thing called the power wall
Is that is you get to a point where you can't actually push the computer faster. There's a thing called the power wall

That's the point where you can no longer dissipate the heat away from the CPU
That's the point where you can no longer dissipate the heat away from the CPU

We actually hit that quite a while ago what you're able to reduce the voltages used on the chips
We actually hit that quite a while ago what you're able to reduce the voltages used on the chips

which meant you could get a bit more and again, but a Platinum getting to the point now where the voltages are, so
which meant you could get a bit more and again, but a Platinum getting to the point now where the voltages are, so

different is really logic zero and a logic one is so low that
different is really logic zero and a logic one is so low that

Actually, you could take it any lower you'd get a leakage between the transistors on the chip itself. And so it's not possible
Actually, you could take it any lower you'd get a leakage between the transistors on the chip itself. And so it's not possible

So you can push the speed in one way the other way you can make the problem
So you can push the speed in one way the other way you can make the problem

Make the program run faster is to split it up into multiple chunks
Make the program run faster is to split it up into multiple chunks

To do them all at the same time
To do them all at the same time

so one way for example to make sandwiches faster is that you butter the bread faster you put the filling in faster you put the
so one way for example to make sandwiches faster is that you butter the bread faster you put the filling in faster you put the

Bread faster the other person if you get two people doing it
Bread faster the other person if you get two people doing it

And then it takes in the same amount of time to make one summary's but you have two people doing it
And then it takes in the same amount of time to make one summary's but you have two people doing it

So they make twice as many sandwiches each time. They make a sandwich same with the computer
So they make twice as many sandwiches each time. They make a sandwich same with the computer

we can either make the computer processor faster or
we can either make the computer processor faster or

We can have multiple cores each working on part of the problem at the same speed and then we have them produce the problem
We can have multiple cores each working on part of the problem at the same speed and then we have them produce the problem

Produce the result faster to do that
Produce the result faster to do that

We need to be able to break the problem down into multiple chunks and x:q each of those chunks separately
We need to be able to break the problem down into multiple chunks and x:q each of those chunks separately

Which is one problem you need to work out and can you break the problem down can be quite simple if you will say
Which is one problem you need to work out and can you break the problem down can be quite simple if you will say

Processing an image you want to say make it 50% the brightness
Processing an image you want to say make it 50% the brightness

Then you can process the top half process the bottom half separately do them at the same time
Then you can process the top half process the bottom half separately do them at the same time

You have the time it takes to process the whole image
You have the time it takes to process the whole image

But the tasks are harder to break down because you need to work out how you want to break down the algorithm to run over
But the tasks are harder to break down because you need to work out how you want to break down the algorithm to run over

different things asymmetric and symmetric
different things asymmetric and symmetric

Multiprocessors aren't really competing for each other. It's not this is how we used to do it
Multiprocessors aren't really competing for each other. It's not this is how we used to do it

This is how we do it now
This is how we do it now

You would find that there are multi person systems back in the 80s and 90s
You would find that there are multi person systems back in the 80s and 90s

Parallel processing was a big thing in the late 80s early 90s
Parallel processing was a big thing in the late 80s early 90s

People were looking at parallel architectures for doing all sorts of things
People were looking at parallel architectures for doing all sorts of things

In fact, one of the things which describes how parallel systems work Flynn's taxonomy was created in 1966. So
In fact, one of the things which describes how parallel systems work Flynn's taxonomy was created in 1966. So

The ideas have been around for a while
The ideas have been around for a while

I think it's more that for a lot of things when you you've got a task that you want to do in different things
I think it's more that for a lot of things when you you've got a task that you want to do in different things

symmetric multiprocessing makes sense for other things
symmetric multiprocessing makes sense for other things

having an asymmetric system
having an asymmetric system

Whether that's your DSP IO processor a GPU a tensorflow type thing and so on makes more sense like that
Whether that's your DSP IO processor a GPU a tensorflow type thing and so on makes more sense like that

So how we design a multiprocessor system is very much based on what you're wanting to do
So how we design a multiprocessor system is very much based on what you're wanting to do

What are you trying to do with it? I mean Flynn's taxonomy is an interesting thing because you then get some really weird
What are you trying to do with it? I mean Flynn's taxonomy is an interesting thing because you then get some really weird

processor types coming up so you can either have a
processor types coming up so you can either have a

system which has got a single instruction stream or
system which has got a single instruction stream or

Multiple instruction streams and a single data stream or you can have multiple data streams
Multiple instruction streams and a single data stream or you can have multiple data streams

So you'll end up with a single instruction stream single data system or most multiple destruction streams single data system single instruction
So you'll end up with a single instruction stream single data system or most multiple destruction streams single data system single instruction

multiple data system or multiple instruction stream
multiple data system or multiple instruction stream

Multiple data systems so a modern multi-core CPU. Well actually at times
Multiple data systems so a modern multi-core CPU. Well actually at times

behave like a single instruction stream system at times behave like a
behave like a single instruction stream system at times behave like a

SIMD single instruction stream multiple data stream system and
SIMD single instruction stream multiple data stream system and

At times behave like a multiple instruction stream
At times behave like a multiple instruction stream

Multiple data system and we end up with these all being used at different times
Multiple data system and we end up with these all being used at different times

The easiest way I think about it as a single instruction stream
The easiest way I think about it as a single instruction stream

Single data stream price is that that's the sort of classic model of a processor
Single data stream price is that that's the sort of classic model of a processor

you've got a set of instructions that your program is executing and
you've got a set of instructions that your program is executing and

You could think of these flowing through the CPU one after the other okay with the occasional branches
You could think of these flowing through the CPU one after the other okay with the occasional branches

Like water flowing through a stream if you look at one point the water flows through at that point
Like water flowing through a stream if you look at one point the water flows through at that point

That's what these two options are doing. They're flowing through the CPU
That's what these two options are doing. They're flowing through the CPU

And each of those instructions is probably going to be loading a value from memory or doing some processing on the value
And each of those instructions is probably going to be loading a value from memory or doing some processing on the value

That's come from memory and then putting it back out to memory. So if we say you I don't know. Let's say it's rendering
That's come from memory and then putting it back out to memory. So if we say you I don't know. Let's say it's rendering

3d graphics you're going to be doing lots of matrix
3d graphics you're going to be doing lots of matrix

multiplications and things on that that you can then pull the data in do the
multiplications and things on that that you can then pull the data in do the

Calculations and write out the new points and so on now what Intel did around who late 90s they introduced what's called the multimedia extensions
Calculations and write out the new points and so on now what Intel did around who late 90s they introduced what's called the multimedia extensions

MMX and that was followed by
MMX and that was followed by

sse sse2
sse sse2

AMD's 3d now and those other things that do different things which basically add one Accord single instruction multiple data instructions
AMD's 3d now and those other things that do different things which basically add one Accord single instruction multiple data instructions

So these instructions are still a single stream of instructions that so we're going to add something. We're going to multiply something
So these instructions are still a single stream of instructions that so we're going to add something. We're going to multiply something

But rather just acting on one piece of data at a time
But rather just acting on one piece of data at a time

They can act on multiple pieces of data and if you think back to that 3d graphics
They can act on multiple pieces of data and if you think back to that 3d graphics

You for example will have your X Y Z coordinates for
You for example will have your X Y Z coordinates for

Say your shape and you normally actually store that as four coordinates because you have the x y&z and then you have a
Say your shape and you normally actually store that as four coordinates because you have the x y&z and then you have a

1 in the vetch because it makes the map slightly simpler. And so you might actually then call that
1 in the vetch because it makes the map slightly simpler. And so you might actually then call that

You need to multiply that by a matrices and with us SIMD type instruction. You can read those four values and
You need to multiply that by a matrices and with us SIMD type instruction. You can read those four values and

Read the four values from one column of your matrix
Read the four values from one column of your matrix

And multiply them all together, which is four separate operations
And multiply them all together, which is four separate operations

But if you can use an SIMD instruction, you can do that in one operation working on four separate bits of data
But if you can use an SIMD instruction, you can do that in one operation working on four separate bits of data

So it multiplies the first player together the second pair together the third player together and the four pair together all in one instruction
So it multiplies the first player together the second pair together the third player together and the four pair together all in one instruction

so they added extra bits new al use new designs for doing things that and they will them to have
so they added extra bits new al use new designs for doing things that and they will them to have

These instructions if your data restricts the data, your pricing is such that you can take advantage of that
These instructions if your data restricts the data, your pricing is such that you can take advantage of that

you can get some significant speed boost because rather than doing four instructions you have to do one and
you can get some significant speed boost because rather than doing four instructions you have to do one and

but you take advantage of what's called data level parallelism the data the pricing you want to do enables you to
but you take advantage of what's called data level parallelism the data the pricing you want to do enables you to

Do those instructions on multiple data options at the same time and you get some sort of speed-up
Do those instructions on multiple data options at the same time and you get some sort of speed-up

It works for some tasks 3d graphics. For example, for other tasks. It's less useful and so you don't benefit from them
It works for some tasks 3d graphics. For example, for other tasks. It's less useful and so you don't benefit from them

but the other thing our CPUs can do is that they have a multiple cores and modern CPUs the intel i7
but the other thing our CPUs can do is that they have a multiple cores and modern CPUs the intel i7

AMD's and so on
AMD's and so on

are all
are all

Multiple instruction multiple data things so they have separate calls each of richer running their own stream of instructions
Multiple instruction multiple data things so they have separate calls each of richer running their own stream of instructions

So they're on different bits of the program or different programs altogether
So they're on different bits of the program or different programs altogether

processing different bits of data still a single stream per processor instance
processing different bits of data still a single stream per processor instance

But unless it's an SIMD bit and so you can have multiple data streams
But unless it's an SIMD bit and so you can have multiple data streams

and
and

So you have them?
So you have them?

Running all of these things and that is pretty much what people think of as parallel processing multi processing of things is you've got multiple
Running all of these things and that is pretty much what people think of as parallel processing multi processing of things is you've got multiple

CPU cores running their own programs processing their own set of data
CPU cores running their own programs processing their own set of data

So we can build up different things
So we can build up different things

So they've been around for years and we've had various different types symmetric asymmetric the different ones of Flynn's Tessa Nanami you've been around
So they've been around for years and we've had various different types symmetric asymmetric the different ones of Flynn's Tessa Nanami you've been around

For a while that leaves us with this weird one in the top right corner of the diagram, which is the multiple instruction stream
For a while that leaves us with this weird one in the top right corner of the diagram, which is the multiple instruction stream

So got multiple streams of instructions
So got multiple streams of instructions

acting on a single data stream
acting on a single data stream

Yeah, they're weird. Not many of them exist these days
Yeah, they're weird. Not many of them exist these days

I think the most prominent example that I've heard of I've never actually had to program it more's the pity is
I think the most prominent example that I've heard of I've never actually had to program it more's the pity is

the space shuttle guidance computer
the space shuttle guidance computer

Left our flowers probably the Space Shuttle guidance computer used a multiple instruction stream single data stream machine
Left our flowers probably the Space Shuttle guidance computer used a multiple instruction stream single data stream machine

And that's one of the reasons you might want to do that. Is that enables you to say do?
And that's one of the reasons you might want to do that. Is that enables you to say do?

Multiple calculations and then get some sort of fault tolerance, perhaps out of it touchdown so you can build parallel processing in different ways
Multiple calculations and then get some sort of fault tolerance, perhaps out of it touchdown so you can build parallel processing in different ways

but the one that we're perhaps most familiar with is that we've got
but the one that we're perhaps most familiar with is that we've got

multiple of CPUs in our computer whether they're physical chips physical cores as it happens to be all their
multiple of CPUs in our computer whether they're physical chips physical cores as it happens to be all their

Multiple cores on the same piece of silicon and if we're doing that we need to make those
Multiple cores on the same piece of silicon and if we're doing that we need to make those

Multiple processors do useful things. So the simplest thing we could do is get the operating system to schedule multiple
Multiple processors do useful things. So the simplest thing we could do is get the operating system to schedule multiple

Programs multiple processes across each of the different CPUs, but that enables had to run multiple programs really good
Programs multiple processes across each of the different CPUs, but that enables had to run multiple programs really good

but it doesn't really give us any speed-up in terms of
but it doesn't really give us any speed-up in terms of

Running a single program to solve a single task and to do that
Running a single program to solve a single task and to do that

we actually need to break the problem down into multiple chunks and
we actually need to break the problem down into multiple chunks and

Execute a chunk of each of that problem on each of the different processes. We've got available to us. Whether that's 2 4 6 8
Execute a chunk of each of that problem on each of the different processes. We've got available to us. Whether that's 2 4 6 8

32
32

However many we've actually got to deal with so we need to break our problem down
However many we've actually got to deal with so we need to break our problem down

Into multiple what often refer to with threads of execution and run them on different?
Into multiple what often refer to with threads of execution and run them on different?

CPU cores
CPU cores

Is that same a1 so that he can decrypt the message and read it? Right? So Alice maybe wants to send another one
Is that same a1 so that he can decrypt the message and read it? Right? So Alice maybe wants to send another one

So she's going to tick this KDF function again
So she's going to tick this KDF function again

She's going to produce a new key and a2 I she's going to send that to Bob
She's going to produce a new key and a2 I she's going to send that to Bob

He's going to take this receiving function a2 now. Bob wants to send a message. So he's going to tick
He's going to take this receiving function a2 now. Bob wants to send a message. So he's going to tick