Re: Hint to Ada newbies

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 10/02/2017 00:12, Robert A Duff wrote:
> Simon Wright <simon@pushface.org> writes:
>
>> I have had to use the power switch to stop a build using -j0! '-j<1 less
>> than the number of cores>' does pretty well.
>
> Which operating system?

Windows in my case, when compiling native, cross or under a virtual 
machine. But there is no need to reset. One should just wait a few 
minutes and then it would go again.

I always change the priority of gprbuild to "below normal" in the task 
manager (and one of the virtual machine too) in order to prevent locks 
like that.

It is not AdaCore to blame, IMO.

A more grave problem is when there are free cores and no free memory. 
This leads to swapping which may require hours if not days to wait 
before the OS becomes responsible again. I had this on ARM Linux quite 
frequently. Maybe this is what Simon had too.

P.S. It would be nice to have a smarter kind of -j0 switch:

1. No new instances if memory or CPU use is greater than some limit 
(e.g. 80%).

2. Spawned instances run on the idle priority.

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