[ale] Help with C project

[Christopher Hagler]

Thanks for the help. Ill give that a try and will post back with results.
On Jan 23, 2016 5:41 PM, "Pete Hardie" <pete.hardie at gmail.com> wrote:

> That might be the problem - the pthread_cond_wait() call must be made from
> the thread you wish to pause
>
> What you might need to do is have some sort of stop flag (protected by a
> mutex) that the scheduler thread will set when it wishes the worker thread
> to stop, and the worker thread has a loop that checks that and if set,
> calls pthread_cond_wait().  Or if the worker thread can determine the need
> to stop by itself, it can do so.
>
> Since (if I understand your project correctly) you want the worker thread
> to run for a limited amount of time, you will need it to have some sort of
> loop to allow it to check for the pause condition (either it check clock
> time to stop at the end of its timeslice, or checks for the scheduler to
> flag it as needing to pause)
>
>
>
> On Sat, Jan 23, 2016 at 5:26 PM, Christopher Hagler <
> haglerchristopher at gmail.com> wrote:
>
>> It is being called from the scheduler thread
>> On Jan 23, 2016 5:24 PM, "Pete Hardie" <pete.hardie at gmail.com> wrote:
>>
>>> Is process_stop() being called from the running thread, or from the
>>> scheduler thread?
>>>
>>> On Sat, Jan 23, 2016 at 2:41 PM, Christopher Hagler <
>>> haglerchristopher at gmail.com> wrote:
>>>
>>>> Thank you for the reply. When I create a process, I give each thread
>>>> their own condition variable because I can control which threads are run. I
>>>> have a function called process_create that in turn calls pthread_cond_init.
>>>> From my understanding a call to pthread_cond_signal does not guarantee
>>>> scheduling order. Threads are not scheduled in the order they call
>>>> pthread_cond_wait. This is why I give each thread their own condition
>>>> variable. The scheduler will call process_start that will call
>>>> pthread_cond_signal on the process struct passed in as a parameter. All of
>>>> that works correctly. However a call to process_stop which calls
>>>> pthread_cond_wait does not seem to work. From what I have read, it all
>>>> seems correct, but the threads continue to run.
>>>> On Jan 23, 2016 12:40 PM, "Pete Hardie" <pete.hardie at gmail.com> wrote:
>>>>
>>>>> It's been a while since I use pthreads directly, but the modus
>>>>> operandi of condition variables is that you declare one before the
>>>>> threads that use it are started, and the threads that you want to wait
>>>>> will call wait() to pause until the another thread signals a change,
>>>>> and then you would check the condition variable value to see if it is
>>>>> the desired value to proceed.
>>>>>
>>>>> On Sat, Jan 23, 2016 at 11:52 AM, Christopher Hagler <
>>>>> haglerchristopher at gmail.com> wrote:
>>>>>
>>>>>> I am working on a home automation project written in C. It allows a
>>>>>> user to automate daily task with open source hardware and software.
>>>>>> However, since I am lacking experience with pthreads, I have run into a
>>>>>> couple of issues that I cant seem to resolve. The intentions of the code
>>>>>> where the issues reside are:
>>>>>>
>>>>>> The project allows drivers to be written as shared objects that,
>>>>>> which in turn, will control a remote hardware device or devices with all
>>>>>> communication happening through shared memory. The Scheduler module will
>>>>>> take the shared object, and schedule it to run via process queues. Once the
>>>>>> process, a struct containing the shared object and an abstraction for a
>>>>>> pthread, runs for its time slot, the scheduler will stop the process and
>>>>>> place it in another process queue. The whole idea was to simulate an
>>>>>> operating system scheduler because potentially there could be a few hundred
>>>>>> threads. This is where the first issue resides. I am having trouble putting
>>>>>> the process to sleep. I have done some research on pthreads and supposedly
>>>>>> this can be accomplished via pthread condition variables. This is the
>>>>>> solution I have attempted, and apparently I have not implemented it
>>>>>> correctly. It will start the process which will run, but when I try to put
>>>>>> it to sleep, it keeps running.
>>>>>>
>>>>>> The second issue is when ever you run the program, it fails to link
>>>>>> the shared object sometimes. However, if you have to quickly run the
>>>>>> program back-to-back, it will start and run fine. I am not sure why this is
>>>>>> happening. It could possibly be linked to my setup, but I am not sure. I am
>>>>>> running Opensuse in Virtual Box.
>>>>>>
>>>>>> Any advice on these issues would be greatly appreciated. I also know
>>>>>> there are a couple of people who have been wanting to learn C, and you are
>>>>>> more than welcome to join the project if you want.
>>>>>>
>>>>>> The code base:
>>>>>> https://github.com/haglerchristopher/automation/tree/development
>>>>>>
>>>>>> Thanks for the help.
>>>>>>
>>>>>> _______________________________________________
>>>>>> Ale mailing list
>>>>>> Ale at ale.org
>>>>>> http://mail.ale.org/mailman/listinfo/ale
>>>>>> See JOBS, ANNOUNCE and SCHOOLS lists at
>>>>>> http://mail.ale.org/mailman/listinfo
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Pete Hardie
>>>>> --------
>>>>> Better Living Through Bitmaps
>>>>>
>>>>> _______________________________________________
>>>>> Ale mailing list
>>>>> Ale at ale.org
>>>>> http://mail.ale.org/mailman/listinfo/ale
>>>>> See JOBS, ANNOUNCE and SCHOOLS lists at
>>>>> http://mail.ale.org/mailman/listinfo
>>>>>
>>>>>
>>>> _______________________________________________
>>>> Ale mailing list
>>>> Ale at ale.org
>>>> http://mail.ale.org/mailman/listinfo/ale
>>>> See JOBS, ANNOUNCE and SCHOOLS lists at
>>>> http://mail.ale.org/mailman/listinfo
>>>>
>>>>
>>>
>>>
>>> --
>>> Pete Hardie
>>> --------
>>> Better Living Through Bitmaps
>>>
>>> _______________________________________________
>>> Ale mailing list
>>> Ale at ale.org
>>> http://mail.ale.org/mailman/listinfo/ale
>>> See JOBS, ANNOUNCE and SCHOOLS lists at
>>> http://mail.ale.org/mailman/listinfo
>>>
>>>
>> _______________________________________________
>> Ale mailing list
>> Ale at ale.org
>> http://mail.ale.org/mailman/listinfo/ale
>> See JOBS, ANNOUNCE and SCHOOLS lists at
>> http://mail.ale.org/mailman/listinfo
>>
>>
>
>
> --
> Pete Hardie
> --------
> Better Living Through Bitmaps
>
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://mail.ale.org/mailman/listinfo/ale
> See JOBS, ANNOUNCE and SCHOOLS lists at
> http://mail.ale.org/mailman/listinfo
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.ale.org/pipermail/ale/attachments/20160123/496dd515/attachment.html>