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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Large number of tasks slows down my program (using debian) - any
 fix?
Date: Fri, 30 Mar 2018 11:04:14 +0200
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Date: 2018-03-30T11:04:14+02:00
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On 2018-03-30 00:33, Shark8 wrote:

> Hm, you shouldn't be hitting the limit with so few tasks. (500 sounds like a lot, but most OSes you'll be using use an integer-ID; meaning something on the order of 2**32 or 2**64.)

It is a simple calculation. Assuming a context switch were around 
1000ns. x 500 tasks / 4 cores = 125ms if all tasks are busy. 125ms is a 
long time.

Another factor is scheduling. Assuming the time quant is 10ms (Windows 
default) and all task are doing pure calculations uninterrupted by any 
I/O, then, again: 10 x 500 / 4 = 1.25s [+125ms] is the time a task gets 
back to a core. 1.3s is an eternity.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de