Attempt at a real world benchmark

Karel Gardas karel.gardas at
Fri Dec 9 13:17:32 UTC 2016

Sorry for hijacking the thread, but

On 12/ 9/16 10:50 AM, Simon Peyton Jones via ghc-devs wrote:
> I have wanted telemetry for years.  ("Telemetry" is the term Microsoft, and I think others, use for the phone-home feature.)

telemetry or better "call-home", this is very dangerous idea to even 
mention in the context of the compiler. In some circles even mentioning 
this may result in losing the trust put in the compiler.

> It would tell us how many people are using GHC; currently I have literally no idea.

For this you don't need any kind of telemetry, but you can use numbers 
from various distributions popularity contests. E.g. debian:

> It could tell us which language features are most used.

Language features are hard if they are not available in separate libs. 
If in libs, then IIRC debian is packaging those in separate packages, 
again you can use their package contest.

> Perhaps it could tell us about performance, but I'm not sure how we could make use of that info without access to the actual source.

So then, how may GHC users trust GHC not sending their own precious 
sources "home" just for GHC performance improvements -- which btw, may 
not be in the interest of the users as they may be happy with current state?

> The big issue is (a) design and implementation effort, and (b) dealing with the privacy issues.  I think (b) used to be a big deal, but nowadays people mostly assume that their software is doing telemetry, so it feels more plausible.  But someone would need to work out whether it had to be opt-in or opt-out, and how to actually make it work in practice.

Privacy here is complete can of worms (keep in mind you are dealing with 
a lot of different law systems), I strongly suggest not to even think 
about it for a second. Your note "but nowadays people mostly assume that 
their software is doing telemetry" may perhaps be true in sick mobile 
apps world, but I guess is not true in the world of developing secure 
and security related applications for either server usage or embedded.

So if I may ask, please no, do not do any telemetry/calling home in GHC 
nor in its runtime system and even do not think about it. This is IMHO 
extremely dangerous.


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