Re: sigqueue code paths

[Charles Cui <charles.cui1984%gmail.com@localhost>]

Thanks Robert for your understanding.
In conclusion, you think the signals are consumed
at the time of context switch. I will keep this information
in mind and see how all functions are connected.

Thanks Charles

2016-07-20 9:15 GMT-07:00 Robert Elz <kre%munnari.oz.au@localhost>:

>     Date:        Wed, 20 Jul 2016 15:28:13 +0200
>     From:        Edgar =?iso-8859-1?B?RnXf?= <ef%math.uni-bonn.de@localhost>
>     Message-ID:  <20160720132813.GR43747%trav.math.uni-bonn.de@localhost>
>
>   | > so before any user code can execute again
>   | ... on this CPU.  What about the other CPUs?  Do all a processes LWPs
> run
>   | on the same CPU?
>
> First, I am certainly no expert, or even particularly knowledgable on
> threading, or lwps, or anything multi-processor related, so hopefully
> someone who is will confirm or correct, but ...
>
> CPUs aren't really what is important here, what matters is that the
> signal gets delivered to the process.   Now it is certainly possible
> that the target process is running on a different CPU than the one
> which is delivering the signal - as I understand it, that is handled
> by forcing the process to (effectively) enter the kernel so it has
> to exit back to user space again, and when that happens it collects the
> signal.   The mechanism to make that happen I will leave for someone
> else to provide details of.
>
> As I understand it, different LWPs can run on different CPUS, but again,
> I'm not sure that is really relevant - most signals (all?) have processes
> as a target, not LWPs.   I believe signals are delivered to just one LWP.
> How that one is selected/controlled I will leave for someone else...
>
> kre
>
>