Le 27/07/2016 17:54, Rainer Weikusat a écrit :
> - resent after someone made Spamhaus remove the @talktalk.net e-mail
> blacklisting entry -
>
>
> Didier Kryn <kryn@???> writes:
>> Le 26/07/2016 12:59, Rainer Weikusat a écrit :
>>> Didier Kryn <kryn@???> writes:
>>>> Le 25/07/2016 01:29, Rainer Weikusat a écrit :
>>>>> Sleeping on a contended mutex is implemented in this way. But that's
>>>>> supposed to be an exceptional case.
>>>> This is why, while advertizing itself as a cool "don't care"
>>>> feature, a mutex is problematic:
>>> I don't know who's advertising that "don't care" use of shared variables
>>> would be "cool" and who's being targetted by this advertising (and I
>>> don't even want to know) but I don't share this opinion. This applies
>>> equally to single-threaded and multi-threaded applications. A mutex is a
>>> synchronisation primitive useful for implementing userspace inter-thread
>>> communication facilities (this is a bit too general).
>> This bias of mine comes from the fact that, in high level
>> languages, mutexes are embedded inside dedicated objects, and the
>> application can assign values to these objects exactly as it would do
>> for any other object (without specific care).
> This could refer to Java 'synchronized things'. But these provide some
> kind of high-level synchronization object called 'a monitor' and
> 'mutexes' (mutual exclusion locks) are just a primitive necessary for
> implementing one. And the "use just like the global variables you'd
> otherwise use" seems to suggest a programming style you seem to consider
> more universal than I do.
>
> Assuming I filled in the blanks halfway correctly, that's still a
> certain style of programming which is already not a terribly good idea
> for a single-threaded application. Using it in a multi-threaded one
> 'multi-threads' the inherent problems. This would be an example how one
> can utilize the potential of more 'modern' technical (shared memory
> multi-processors aka 'multicore CPUs') to achieve the same effect
> (create a total chaos) much faster :->.
>
> [...]
>
>
Never have written a single line of Java. It takes me a strong
motivation to start learning another language.
Mutex-protected objects can be built in C++, and are part of the
Ada language. It is difficult to decide what Ada should do in this case;
I don't know if the issue has been discussed but this kind of object
looks to me like a difficult compromise.
Didier
::
Re: [DNG] Wirth's law
