
Ask HN: Which line of code you have written will be executed the most? - jamesmstone
The other day I was trying to determine which line of code I have written will get run the most?<p>I think for me it would be a for loop in a cron job I run on work&#x27;s servers -  not very exciting! I am sure HN has many more interesting examples.<p>maybe you have written code:<p>- deep in an OS that handles memory management?<p>- that is deeply distributed?<p>- that is in every JS lib? ~~cough cough left pad cough~~<p>- maybe it is an accidental infinite loop you once wrote?
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akg_67
20+ years ago, I wrote the Fortran code that polls the vibration of a turbine
shaft every 1/100th of second. That facility is still in operation, the system
I worked on is still in operation, those type of facilities run 24x7x365 and
rarely have a downtime where system or turbine might be taken offline for
long. I guess my code has been running every 1/100th of second for 20 years or
so. I don't think I can write any code that will beat that little piece of
code in frequency of use.

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uberman
At a fortune 100 company I consulted at, developers were rewarded for writing
efficient code that was frequently reused. This was literally micro-
transaction recognition and rewards a decade prior to anything resembling
today's micro-transaction cloud billing.

I wrote the billing/logging system and I am certain the main "method call
logger" is by far the most frequently executed code I have ever written. It
was called by any method that the author wanted to be compensated for. Alas, I
was not allowed to include the call to this method in the compensation pool
:-(

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seanhunter
I spent a week or so pouring through valgrind and profile output optimising
the very heart of the code for a Monte Carlo simulation at a major investment
bank. Some of the lines of code I wrote in that week will have been executed
billions of times per day since I pushed them back in 2007 or so. They are
still being used.

I got a good overall speedup (over 5% in code that was already pretty well-
optimised) but by far the most valuable optimisation I did was one of the most
basic - hoisting variables out of for loops. This kind of thing

    
    
        for(int i=0; i<something; ++i) {
           int x=0;
           //...do something with x  
        }
    
    

changes to...

    
    
        int x;
        for(int i=0; i<something; ++i) {
           x=0;
           //...do something with x  
        }
    
    

There are slightly more subtle versions of that, but at the time none of the
compilers we were using (gcc 3.2, solaris 8 C++ compiler or Visual C++ 7)
could optimise that without you doing the hoist yourself.

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dave_sid
// TODO

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newswasboring
For me it has to be the data analysis pipeline I wrote for one of the biggest
semiconductor manufacturing fabs in the world. Its is triggered for every lot
they produce (a lot is usually 25 wafers). This company holds the majority
market share in semi manufacturing space, so it is more than coin flip likely
that the device you are using to read this contains a chip which was analyzed
by my pipeline. (So if it breaks due to thermal issues... sorry).

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mod
I wrote the backend for a large saas that is in the business of pushing
notifications to ios, Android, and browsers.

It's not as cool as being a frequent call at the OS level, but pretty good for
an ex web developer.

I think it's very likely still in use, in some part, and surely into the
billions of deliveries, so who knows how many executions of some inner loops
or whatever.

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quickthrower2
Probably some code I wrote to see how long a for loop would take in js looping
a billion times. Not too exiting either

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austincheney
On the front end it’s some code that walks the DOM in a way the standard DOM
don’t. It can get DOM nodes by node type. On the backend it’s some code that
walks the file system for systems automation.

Simple primitive stuff like that tends to get embedded in a variety of other
automation.

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eb0la
I guess mine is a type-conversion class inside an apache beam job. Usually
it's running on a streaming job; but when you launch it as dataflow batch job
it has 30-40 workers running it at once for several hours.

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rl3
Technically: it's things inside of rendering or sim loops.

Philosophically: print debugging.

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qlk1123
Some architecture-dependent things in context-switch/signal handling path.

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longcommonname
Rewrote a logging framework that logged petabytes per day.

------
scott31
if err != nil {

~~~
tmaly
I was going to post the same.

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joezydeco
Lots of interrupt and timer tick handlers. The early ones ran every 500
microseconds and those went out the door 25 years ago.

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luhego
A decorator that checks if the user is logged before running a GraphQL
mutation.

@login_required

def mutate(...):

------
nxpnsv

        import numpy

