Re: _SC_SIGQUEUE_MAX

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

Thanks Christos for these comments!
In terms of the new fields exposed by sched_param, those are only for
testing convenience, if we decide to expose those to users, we need to
consider carefully.

In terms of the testing method proposed by you, did you already implement
and test
or want me to provide the test?

Thanks Charles.

2016-06-22 14:53 GMT-07:00 Christos Zoulas <christos%zoulas.com@localhost>:

> On Jun 22,  1:23pm, charles.cui1984%gmail.com@localhost (Charles Cui) wrote:
> -- Subject: Re: _SC_SIGQUEUE_MAX
>
> | Any comments on the tests?
>
> Yes, I am not finished yet testing and looking. Here are some preliminary
> ones:
>
> 1. You've added more fields to sched_params. This should not be done
> lightly
>    because the system call interface is an ABI. If we want to keep them we
>    should version the syscall. There are more questions about the change.
>    Is this the right set of fields? How about exposing others like depth?
>    Should those fields be settable? Do they belong in the sched_params if
>    they are not? Even if we accept all of that they changes should be
>    documented...
> 2. On the unit test itself. It is fine what you did to check if the
> priority
>    of the thread was changed after it took the mutex lock. I would have
>    also written the test like:
>         create thread 1
>         make thread 1 low priority
>         print message with priority info
>         grab mutex.
>         print message with priority info
>         release mutex
>         print message with priority info
>
>         create thread 2
>         make thread 2 high priority
>         print message with priority info
>         attempt to grab same mutex as thread 1
>         print message with priority info
>
>         see that thread 1 runs before thread 2
>
>    instead of using thread 1 and main to make things more obvious, but it
>    is fine.
>
> I am running a system with the patches and testing it... Let's discuss
> the sched_params syscall modification... We should also look what other
> fields other OS's expose. Once we decide that you can add documentation
> and I can start committing the changes.
>
> christos
>