OT (partially): about promotion of integers

[Walter Bright]

On 12/12/2012 2:17 PM, bearophile wrote:
> Two comments:
> - I've seen Facebook start from PHP, go to PHP compiled in some ways, and lately
> start to switch to faster languages, so when you have tons of servers space and
> electricity used by CPUs becomes important for the bottom line. On the other
> hand on similar servers lot of other people use languages where there is far
> more than your 5% overhead, as Java.

I know people who use Java on server farms. They are very, very, very cognizant 
of overhead and work like hell trying to reduce it, because reducing it drops 
millions of dollars right to the bottom line of profit.

Java makes no attempt to detect integer overflows.


> Often small performance differences are not
> more important than several other considerations, like coding speed, how much
> easy is to find programmer, how cheap those programmers are, etc, even on server
> farms.

The problem they have with C++ is it is hard to find C++ programmers, not 
because of overflow in C++ programs.


> - If your code is buggy (because of overflows, or other causes), its output can
> be worthless or even harmful. This is why some people are using OcaML for
> high-speed trading (I have given two links in a precedent post), where bugs risk
> being quite costly.

I personally know people who write high speed trading software. These people are 
concerned with nanosecond delays. They write code in C++. They even hack on the 
compiler trying to get it to generate faster code.

It doesn't surprise me a bit that some people who operate server farms use slow 
languages like Ruby, Python, and Perl on them. This does cost them money for 
extra hardware. There are always going to be businesses that have inefficient 
operations, poorly allocated resources, and who leave a lot of money on the table.