9:59:59.000,9:59:59.000
So Hi there, everyone.

9:59:59.000,9:59:59.000
My name is Chandler Carruth.

9:59:59.000,9:59:59.000
I work for Google

9:59:59.000,9:59:59.000
I work on our C++ language platform

9:59:59.000,9:59:59.000
I work on our C++ compilers

9:59:59.000,9:59:59.000
specifically the Clang and ?

9:59:59.000,9:59:59.000
And I'm here to talk to you a little about performance.

9:59:59.000,9:59:59.000
and efficiency, and making code fast,

9:59:59.000,9:59:59.000
and all the different things that go into that.

9:59:59.000,9:59:59.000
But before I do too much

9:59:59.000,9:59:59.000
I want to give actually give you guys a little bit of a

9:59:59.000,9:59:59.000
one might say are expectations.

9:59:59.000,9:59:59.000
Because I have been reading the twitter feed

9:59:59.000,9:59:59.000
from all these folks, that talk about all these crazy good questions

9:59:59.000,9:59:59.000
I just want you guys to essentially know this is my view

9:59:59.000,9:59:59.000
of what Performance 101 should be.

9:59:59.000,9:59:59.000
Okay? This is going to be kind of an intro talk.

9:59:59.000,9:59:59.000
You guys are hard core, really deep performance nuts.

9:59:59.000,9:59:59.000
You may be a little bit bored, and please be kind,

9:59:59.000,9:59:59.000
because I'm going to gloss over some things

9:59:59.000,9:59:59.000
you could go into thoroughly if you really want to

9:59:59.000,9:59:59.000
We're going to talk about efficiency, performance,

9:59:59.000,9:59:59.000
algorithms and data structures.

9:59:59.000,9:59:59.000
And the first thing we are going to do is we're not going to talk about them.

9:59:59.000,9:59:59.000
We're going to talk about why anyone cares about them.

9:59:59.000,9:59:59.000
How many folks here think it's really important to have high performance in C++? Like certain that it's super important?

9:59:59.000,9:59:59.000
Everyone thinks it's important!

9:59:59.000,9:59:59.000
And the folks here have a really clear idea why performance is important.

9:59:59.000,9:59:59.000
Now, all the people who didn't raise their hands the second time,

9:59:59.000,9:59:59.000
Please reconsider raising your hand the first time.

9:59:59.000,9:59:59.000
We actually need to understand why performance is important in C++,

9:59:59.000,9:59:59.000
before we actually decide it's important, we're going to care a lot about it.

9:59:59.000,9:59:59.000
I'm going to tell you why I care about performance in C++.

9:59:59.000,9:59:59.000
Most of it comes down to a quote from Nicolas Werth.

9:59:59.000,9:59:59.000
Which I will try to pronounce correctly but fail miserably.

9:59:59.000,9:59:59.000
I actually really like a lot of our stuff,

9:59:59.000,9:59:59.000
I think he really encapsulates a lot of my thoughts about the philosophy of software here.

9:59:59.000,9:59:59.000
The software is getting slower more rapidly than (1:58)

9:59:59.000,9:59:59.000
But that's what happened

9:59:59.000,9:59:59.000
We now have to care about

9:59:59.000,9:59:59.000
And we essentially

9:59:59.000,9:59:59.000
You have to choose one

9:59:59.000,9:59:59.000
We're going to choose small

9:59:59.000,9:59:59.000
The other problem

9:59:59.000,9:59:59.000
What do we do about the battery

9:59:59.000,9:59:59.000
How many folks here have charged their phone today

9:59:59.000,9:59:59.000
That's a problem.

9:59:59.000,9:59:59.000
That's not a feature, that's a bug.

9:59:59.000,9:59:59.000
How many

9:59:59.000,9:59:59.000
We've entered

9:59:59.000,9:59:59.000
Power became relevant

9:59:59.000,9:59:59.000
Power efficient instructions

9:59:59.000,9:59:59.000
Optimizing for power usage

9:59:59.000,9:59:59.000
Because this is mostly total junk science.

9:59:59.000,9:59:59.000
Here is the number one

9:59:59.000,9:59:59.000
Finish running the program

9:59:59.000,9:59:59.000
The faster your software runs, the lest

9:59:59.000,9:59:59.000
If I run

9:59:59.000,9:59:59.000
But it's not, okay?

9:59:59.000,9:59:59.000
Here's the thing.

9:59:59.000,9:59:59.000
We've only

9:59:59.000,9:59:59.000
We figured out how to turn them off.

9:59:59.000,9:59:59.000
if you have a

9:59:59.000,9:59:59.000
the way it conserves power is by turning itself off

9:59:59.000,9:59:59.000
The more

9:59:59.000,9:59:59.000
So we actually want to make code faster

9:59:59.000,9:59:59.000
There are some extreme exceptions to it

9:59:59.000,9:59:59.000
But 99.999999% of the time

9:59:59.000,9:59:59.000
But batteries aren't the only

9:59:59.000,9:59:59.000
You'll note that

9:59:59.000,9:59:59.000
The only thing it is doing is taking electricity and turning it into heat.

9:59:59.000,9:59:59.000
That is it's job

9:59:59.000,9:59:59.000
And unfortunately, electricity costs a lot of money

9:59:59.000,9:59:59.000
And so power becomes very, very important

9:59:59.000,9:59:59.000
And I find it interesting