A very interesting slide deck comparing sync and async IO

[Sean Kelly via Digitalmars-d]

On Friday, 4 March 2016 at 06:55:29 UTC, Shachar Shemesh wrote:
> On 03/03/16 19:31, Andrei Alexandrescu wrote:
>> https://www.mailinator.com/tymaPaulMultithreaded.pdf
>
> On a completely different note, me and a colleague started a 
> proof of concept to disprove the claim that blocking+threads is 
> slower. We did manage to service several tens of thousands of 
> simultaneous connections using the one thread per client mode, 
> proving that the mere context switch is not the problem here. 
> Sadly, we never got around to bringing the code and the tests 
> up to the level where we can publish something, but, at least 
> in the case where a system call is needed in order to decide 
> when to switch fibers, I dispute the claim that non-blocking is 
> inherently faster.

It's not inherently faster. It just scales better in real-world 
scenarios, assuming a limited number of worker threads. Blocking 
IO is actually often fine in synthetic tests and in server to 
server, but in real world situations where some clients have 
modem-level bandwidth, a blocking write can ruin you.