On 07/09/15 08:32, Cyrille Artho wrote:
Hi Sebastian,
I was not aware that deadlock detection was an objective.
It would be good to first clarify the requirements for a new mutex
implementation. This is why I created the ticket. It doesn't make sense
to add something which will be replaced in some months if we add OMIP
support.
Cyclic lock usage could be detected but performance would decrease.
I think cyclic lock usage detection will be a simple side-effect of the
horizontal nesting support. On SMP this is crucial since otherwise we
may end up in a deadlock at spin lock level and this is bad.
Furthermore, this would also create possible issues with scheduling
fairness, so we would have to discuss that first.
What do you mean with scheduling fairness problems?
Deadlock detection for shared conditionals would be difficult, at
least in the general case.
On Mon, Sep 7, 2015 at 3:04 PM, Sebastian Huber
<sebastian.hu...@embedded-brains.de> wrote:
Hello Saurabh,
On 05/09/15 01:52, Saurabh Gadia wrote:
This is the patch for solving priority inversion problem for uniprocessor
architecture. It works correctly for all test cases on master. For 4.11 the
patch get applied cleanly but the branch does not compile because of some
rbtree error(unrelated to project). Github link:
https://github.com/saurabhgadia4/rtems/tree/nested-mutex
I reviewed your patch. Basically you replaced the LIFO list of priorities
with a sorted list? Does it work with timeouts and external priority changes
(e.g. task A blocks on a mutex owned by O, another task B raises the
priority of A, will this raise the priority of O?)
Since all tests pass, test sptests/spsem03 passes, which shows that your
implementation doesn't support horizontal nesting.
There is no deadlock detection.
Please have a look at:
https://devel.rtems.org/ticket/2412
I think the suggested implementation would even work on SMP systems quite
well.
--
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.
--
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.
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