Re: Poor tasking performance

["Robert I. Eachus" <rieachus@comcast.net>]

Adrian Knoth wrote:

> Is that normal? Only by adding one task which hangs in Get_Line
> increases the load so much?
> 
> Environment is Linux 2.6.7 with Debian gcc-3.3 (unstable).

First, let me say you are lucky to get working results with that 
combination. Most Ada users have skipped gcc-3.3.  (I haven't switched 
from 3.15p to gcc-3.4 yet, but that is my intent at some point.)

But I don't think that your question can be answered in an Ada context. 
  This is definitely an area where the underlying OS implementation of 
reading from the console is going to account for most of the overhead.

If you are using Get_Immediate in Text_IO, you could switch to line at a 
time reading and see if that helps.  But I suspect that it won't--the OS 
needs to poll the UART that buffers keyboard input at a certain rate to 
avoid losing characters. With a different keyboard, or keyboard driver, 
you might get very different results.


-- 

                                           Robert I. Eachus

"Reason and experience both forbid us to expect that national morality 
can prevail in exclusion of religious principles." -- George Washington