Hi all, I have updated my proposal on both melange[0] and github[1], if you have any comment please tell me. Thank you!
Updates: 1. Modify the plan scheduling according to Gedare comments, thank you Gedare! 2. Add a plan for 'Improve the classic CV capabilities, such as dealing with priority inversion', this feature is mentioned on wiki[2], and i have a basic understand about its meaning. But if anyone can explain more deeper i will be grateful for you. 0. https://www.google-melange.com/gsoc/proposal/review/student/google/gsoc2014/json1984/5629499534213120 1. https://github.com/cloud-hot/proposal/blob/master/proposal.md 2. http://wiki.rtems.org/wiki/index.php/Condition_Variables 2014-03-10 20:46 GMT+08:00 zhang json <json.a.zh...@gmail.com>: > Hi all, > > I have updated my proposal, and your comments are welcome! > > https://github.com/cloud-hot/proposal/blob/master/proposal.md > > > > 2014-03-04 21:49 GMT+08:00 zhang json <json.a.zh...@gmail.com>: > > >> 2014-03-04 21:32 GMT+08:00 Gedare Bloom <ged...@rtems.org>: >> >> On Mon, Mar 3, 2014 at 7:51 PM, zhang json <json.a.zh...@gmail.com> >>> wrote: >>> > Dear all, >>> > >>> > Recently i have been study the RTEMS code and all related resource >>> about >>> > condition variables. At the meantime i am preparing a proposal for >>> this GSOC >>> > project. Although it is just a skeleton draft, i think it is better to >>> throw >>> > it ASAP. So that everyone can give me some valuable suggestions. And my >>> > proposal is managed by github, so if you have any comments you can >>> just open >>> > a new issue to me. Waiting for all your comments! Thank you! >>> > >>> > https://github.com/cloud-hot/proposal >>> > >>> Please add yourself and the link to your proposal to the table at >>> >>> http://wiki.rtems.org/wiki/index.php/RTEMSSummerOfCode#Students.27_Proposals >>> >>> Done+ >> >> >>> > >>> > >>> > 2014-03-04 8:42 GMT+08:00 zhang json <json.a.zh...@gmail.com>: >>> > >>> >> Hi Sebastian, >>> >> >>> >> Thank you for your reply! >>> >> >>> >> 2014-03-03 15:06 GMT+08:00 Sebastian Huber >>> >> <sebastian.hu...@embedded-brains.de>: >>> >> >>> >>> On 2014-03-02 03:40, zhang json wrote: >>> >>>> >>> >>>> >>> >>>> 2014-02-28 15:15 GMT+08:00 Sebastian Huber >>> >>>> <sebastian.hu...@embedded-brains.de >>> >>>> <mailto:sebastian.hu...@embedded-brains.de>>: >>> >>>> >>> >>>> >>> >>>> On 2014-02-28 01:12, zhang json wrote: >>> >>>> >>> >>>> >>> >>>> 2014-02-26 1:07 GMT+08:00 Gedare Bloom <ged...@rtems.org >>> >>>> <mailto:ged...@rtems.org> >>> >>>> <mailto:ged...@rtems.org <mailto:ged...@rtems.org>>>: >>> >>>> >>> >>>> >>> >>>> >>> >>>> You may like to read >>> >>>> >>> >>>> >>> http://wiki.rtems.org/wiki/__index.php/SMP#Non-Preempt___Mode_for_Mutual_Exclusion >>> >>>> >>> >>>> >>> >>>> < >>> http://wiki.rtems.org/wiki/index.php/SMP#Non-Preempt_Mode_for_Mutual_Exclusion >>> > >>> >>>> in addition to the Condition Variables project page. >>> You >>> >>>> can search >>> >>>> for "condition variable" in a search engine to get some >>> >>>> useful >>> >>>> background material. More below. >>> >>>> >>> >>>> Thank you for your reply. I will search and prepare this >>> project >>> >>>> and a >>> >>>> draft >>> >>>> will be post ASAP. >>> >>>> >>> >>>> On Tue, Feb 25, 2014 at 9:45 AM, zhang json >>> >>>> <json.a.zh...@gmail.com <mailto:json.a.zh...@gmail.com> >>> >>>> <mailto:json.a.zh...@gmail.com >>> >>>> <mailto:json.a.zh...@gmail.com>__>> >>> >>>> >>> >>>> wrote: >>> >>>> > Hi all, >>> >>>> > >>> >>>> > I am a student who is preparing for participating >>> the >>> >>>> GSOC2014, and from >>> >>>> > 'Open Project' i found a interesting project >>> 'Condition >>> >>>> Variables'. So i >>> >>>> > want to know the basic information about the status >>> of >>> >>>> this >>> >>>> project. >>> >>>> > >>> >>>> > There is a bug [1] which is maybe related to it but >>> it >>> >>>> seems that >>> >>>> > 'Condition Variables' is not the main problem of >>> this >>> >>>> bug. So >>> >>>> my confusion >>> >>>> > is blow: >>> >>>> > >>> >>>> > 1. As one of the classic operating system >>> >>>> synchronization >>> >>>> primitives whether >>> >>>> > RTEMS has a basic 'Condition Variables' support? >>> >>>> RTEMS lacks a condition variable (monitor) >>> implementation >>> >>>> within the >>> >>>> classic API located in cpukit/rtems/*, and also within >>> the >>> >>>> supercore >>> >>>> "kernel" interface located in cpukit/score/*. There is >>> >>>> condition >>> >>>> variables support in posix, as the >>> >>>> cpukit/posix/include/rtems/__posix/condimpl.h. >>> >>>> >>> >>>> >>> >>>> OK, i have some rtems experience so i will first design the >>> CV >>> >>>> and >>> >>>> implement it >>> >>>> in score component, then warp it into classic api. >>> >>>> >>> >>>> >>> >>>> We already have a CV implementation in RTEMS. It is currently >>> only >>> >>>> available for the PThread API. What we need is a definition >>> for the >>> >>>> Classic API and a shared implementation. We should also address >>> >>>> potential >>> >>>> priority inversion issues of CV in combination with priority >>> based >>> >>>> schedulers. >>> >>>> >>> >>>> Could you tell me where i can find the code of CV implementation >>> for the >>> >>>> Pthread API? and CV is also implemented in the score? then needed >>> work >>> >>>> is to >>> >>>> implement a classic API for CV and shared its implementation? >>> >>> >>> >>> >>> >>> Answering this question gives you a good opportunity to discover the >>> >>> RTEMS sources. >>> >>> >>> >> Yeah, recently i have been studying the RTEMS code. >>> >> >>> >>>> >>> >>>> >>> >>>> > 2. If answer not from 1, what is the requirement of >>> the >>> >>>> implementation? >>> >>>> It should implement a classic API condition variable >>> that >>> >>>> can be >>> >>>> similar to the classic API implementation of semaphore >>> >>>> (cpukit/rtems/include/rtems/__rtems/sem.h and >>> semimpl.h). >>> >>>> The >>> >>>> >>> >>>> condition >>> >>>> variable should be implemented in the supercore >>> >>>> (cpukit/score) and >>> >>>> that implementation should be shared by the posix >>> condvar >>> >>>> and the >>> >>>> classic API condition variables. >>> >>>> >>> >>>> Yeah, i will refer to implementation of semaphore and >>> mutex. And >>> >>>> there >>> >>>> are lots >>> >>>> of open source CV implementation for many os, such freebsd, >>> >>>> netbsd, linux, >>> >>>> eCos. About linux its license may be is not compatible with >>> >>>> RTEMS, so i >>> >>>> just >>> >>>> learn its idea instead of code. >>> >>>> >>> >>>> > 3. Whether its implementation should support SMP? >>> >>>> > >>> >>>> The implementation must support SMP. >>> >>>> >>> >>>> Yeah, it will be a challenge. But as i know the SMP support >>> of >>> >>>> RTEMS is >>> >>>> becoming better, some SMP synchronization primitives have >>> been >>> >>>> support, >>> >>>> like >>> >>>> atomic. I am wondering whether semaphore and mutex is >>> supported >>> >>>> SMP? >>> >>>> >>> >>>> >>> >>>> The SMP support in RTEMS is currently based on a Giant lock. So >>> >>>> most >>> >>>> objects simply work. >>> >>>> >>> >>>> And in the future should the Giant lock be removed? so now should we >>> >>>> consider >>> >>>> this situation, or we can first use Giant lock and then replace it >>> with >>> >>>> other >>> >>>> safe lock later. >>> >>> >>> >>> >>> >>> Yes, the Giant lock must be removed to get a real-time operating >>> system >>> >>> that can compete on the market. Removing the Giant lock is however >>> a major >>> >>> challenge and beyond a GSoC project. >>> >>> >>> >>> http://www.rtems.org/wiki/index.php?title=SMP#Fine_Grained_Locking >>> >>> >>> >> Maybe i can consider it as a future work after GSOC project. >>> >> >>> >>> >>> >>> >>> >>> -- >>> >>> Sebastian Huber, embedded brains GmbH >>> >>> >>> >>> Address : Dornierstr. 4, D-82178 Puchheim, Germany >>> >>> Phone : +49 89 189 47 41-16 >>> >>> Fax : +49 89 189 47 41-09 >>> >>> E-Mail : sebastian.hu...@embedded-brains.de >>> >>> PGP : Public key available on request. >>> >>> >>> >>> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG. >>> >> >>> >> >>> >> >>> >> >>> >> -- >>> >> Json Zhang >>> >> Best Regards >>> > >>> > >>> > >>> > >>> > -- >>> > Json Zhang >>> > Best Regards >>> > >>> > _______________________________________________ >>> > rtems-devel mailing list >>> > rtems-devel@rtems.org >>> > http://www.rtems.org/mailman/listinfo/rtems-devel >>> > >>> >> >> >> >> -- >> Json Zhang >> Best Regards >> > > > > -- > Json Zhang > Best Regards > -- Json Zhang Best Regards
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