Re: [boost] expected/result/etc

Subject: Re: [boost] expected/result/etc
From: Domagoj Saric (dsaritz_at_[hidden])
Date: 2016-02-07 14:02:47

On 6.2.2016. 21:48, Emil Dotchevski wrote:
> Another stated
> concern is that exception handling introduces overhead throughout the
> program even when exceptions are not being propagated, however such
> overhead (if any) is limited to function call and exit points. In
> performance-critical contexts function calls are too expensive with or
> without the added overhead of exception handling, and the solution is to
> inline the function. In that case all function call overhead disappears,
> including the exception handling overhead.

However
* this reasoning is only valid (and even then not fully) in synthetic 
tests/non-real world analysis - i.e. 'my program is the only one on the 
system' - on a real system, this reasoning is merely the number one 
licence to produce bloatware as there everything is 'performance 
critical' - your 'non critical' (i.e. fatter and slower than necessary) 
code (in addition to contributing to OTA and flash storage costs, IO, 
fragmentation...) might be loaded and/or executed (or simply occupy the 
virtual address space) at the same time that another app is trying to 
"squeeze the most of a user's device" (i.e. running its 'critical' part)
* inlining is, in general, a primitve bruteforce solution that can only 
exacerbate the problem of bloatware (discussed this in more detail 
relatively recently with Andrey Semashev)
* even the very latest MSVC compiler cannot inline functions that 
contain certain types of EH (even something simple as having a by-value 
parameter that has a non-trivial destructor)...

-- 
"What Huxley teaches is that in the age of advanced technology, 
spiritual devastation is more likely to come from an enemy with a 
smiling face than from one whose countenance exudes suspicion and hate."
Neil Postman