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Starting a tech startup with C++

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Re: Starting a tech startup with C++

#51

Post by emcq »

samfisher83 wrote: post #20

I would find it hard to believe that c++ can be that much faster for many websites since the bottleneck would be the I/O subsystem. I don't understand how they are getting this 40x speed up. I wonder what the benchmark looks like.

In an optimized system the bottleneck will be I/O. However elements like serialization, many function calls, and extraneous memory copies chips away at performance to the point it matters and its difficult to address these problems directly in languages outside of C/C++.

Today you can get 15MB/s to S3. A not uncommon mysql node might do 10MB/s. Good luck trying to push that throughput with python or Ruby on a single process through a http response. Much faster I/O exists with sequential HD, SSD, and RAM based I/O. Most networks are built with 1Gbit Ethernet allowing 100MB/s that won't get saturated in the slower languages without going parallel which can increase total system complexity and lines of code.

Re: Starting a tech startup with C++

#52

Post by jcyw »

samfisher83 wrote: post #20

I would find it hard to believe that c++ can be that much faster for many websites since the bottleneck would be the I/O subsystem. I don't understand how they are getting this 40x speed up. I wonder what the benchmark looks like.

Its more like, with 2gb ram and 2.0ghz cpu, how many requests can you handle? Its not surprising language like C++ would win.

Re: Starting a tech startup with C++

#53

Post by thrownaway2424 »

bnastic wrote: post #4

It's sad that you need to justify using one of the most established and longest serving languages/platforms ever.

Indeed, the given strawman alternative languages (Ruby and Python) are far, far worse for productivity. Python changes are totally unreviewable since one cannot in any way reason about the correctness of a function call without reading the definition of the function itself, and all the functions to which it passes the arguments, all the way down, which of course takes forever. At least with C++ you can reason that if a change compiles it has not made any dramatically stupid type errors. You still need to think about whether any unnecessary temporaries or copies were made, or questionable assignments, but you need only think about that one level deep. Is seems to me far more dangerous to suggest writing new code in Python.

Re: Starting a tech startup with C++

#54

Post by JoeAltmaier »

jcyw wrote: post #50

No one doubs the performance of C++. What I would really like to see is arguments about speed of development, ease of testing, etc. This articles argues alot about language features or libraries, but what about the bigger picture? It is not enough for the HTTP server be fast. It also needs to do REST API, auth, etc. How does that compare to for example node/js.

One C++ advantage is, at 40X the horsepower, they didn't have to deal with scaling configuration right away. They can put that off, and deal with proving their product instead.

Re: Starting a tech startup with C++

#55

Post by jcyw »

JoeAltmaier wrote: post #54
jcyw wrote: post #50

No one doubs the performance of C++. What I would really like to see is arguments about speed of development, ease of testing, etc. This articles argues alot about language features or libraries, but what about the bigger picture? It is not enough for the HTTP server be fast. It also needs to do REST API, auth, etc. How does that compare to for example node/js.

One C++ advantage is, at 40X the horsepower, they didn't have to deal with scaling configuration right away. They can put that off, and deal with proving their product instead.

The argument is you do not need a load balancer because performance of one host is good enough. But that would become a single point of failure. And thats why AWS is so awesome. Start with an autoscaling group when you create your ec2 instance, you dont really need alot configuration.

Re: Starting a tech startup with C++

#56

Post by nickpsecurity »

steveklabnik wrote: post #42
n00b101 wrote: post #35

Earlier quoted context omitted.

> there are now languages that can compete in terms of performance Such as?

If Rust code is slower than equivalent C++, it's a bug. We track performance bugs, please file them :)

I like the quip but that's barely an answer given OP avoided Rust specifically. There's a difference between a high-performing language in development (and debugging) vs a high-performing language with over a decade of work into its tooling and support. The latter's strengths and weaknesses are known through and through with many implementation and library problems likely worked out long ago.

So, if it was apples to apples, I'd probably cite Ada, Eiffel, Modula-3, or Component Pascal as the closest to C++ in terms of performance and key features while being safer and more readable. Each has had years of work, support from commercial sector (except Modula-3 now), and programs tend to work more than break after a compile.

That said, your Rust work is exciting and I hope it gets in that same category. It's just so new and evolving that its not in C++'s class in terms of risk or predictability. Not yet.

Re: Starting a tech startup with C++

#57

Post by pjc50 »

petke wrote: post #31
pjc50 wrote: post #26

Earlier quoted context omitted.

Because copying the entire in-memory database you're using on every function call is kind of expensive?

Most often you can pass stack values to and from functions without copying. This is because of move constructors, and named return value optimization. Often its slower to use pointers (the indirection). For instance this does not do any expensive copies: std::string getStr() { auto huge_str = getDatabaseDump(); return huge_str; } void readStr(const std::string& str ){ //read str.. } int main() { auto str = getStr();…

But std::string is a wrapper for a heap allocation, and a reference also incurs the same indirection cost as a pointer?

Re: Starting a tech startup with C++

#58

Post by kahseng »

melling wrote: post #21
hakcermani wrote: post #18

Wondering how Swift will play in this arena now that is open sourced - and performance ? According to this ( http://www.primatelabs.com/blog/2014/12/swift-performance ) for some workloads does approach C++.

What's the state of Swift for web development? Are web frameworks starting to appear?

There's perfect.org that came out in Nov 2015.

Re: Starting a tech startup with C++

#59

Post by ufmace »

I wonder why the choice of language is framed as being between C++ and Ruby/Python? Yes, C++ is known for being fast while suffering from a shortage of easy libraries and being more verbose to write and intellectually challenging to write in, while the mainstream dynamic languages are known for being not so fast but having a vast array of handy, easy to integrate libraries and being fast to develop in. But I think there's a number of choices between the two that seem worth considering.

C#/.NET doesn't get a lot of love from the startup community, but it's mature, stable, fast, full of advanced features, and has good library support.

Java and other JVM languages have similar advantages and better compatibility with Unix-based OSes. Java itself is a little long in the tooth, but there is the option of alternate JVM languages.

I'd probably be most tempted to check out Go if I was working on something that absolutely had to wring the best possible performance out of my hardware. I don't honestly know that much about it, but it has a reputation for getting you most of the performance of C++ without the complexity.

But I will say that if the author has lots of experience in C++ and comfort with the ecosystem, and not much in any of those other languages, then by all means go with C++. Getting your product out there is more important than getting the perfect language.

Re: Starting a tech startup with C++

#60

Post by nickpsecurity »

jcyw wrote: post #52
samfisher83 wrote: post #20

I would find it hard to believe that c++ can be that much faster for many websites since the bottleneck would be the I/O subsystem. I don't understand how they are getting this 40x speed up. I wonder what the benchmark looks like.

Its more like, with 2gb ram and 2.0ghz cpu, how many requests can you handle? Its not surprising language like C++ would win.

Funny you say that given I'm dusting off an old laptop that has a 1.xGhz Core Duo CPU and 2GB of RAM. It's the next one to be used for performance and stress testing. The reason? Anything that can't run snappy on that box is just bloated or wasting resources. Lean, native code tends to do the job nicely. :)

Note: Also good to do it on cheap, throwaways because this sort of thing burns out the CPU's. Better that box than my main one.

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