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On 10/09/2018 10:53, Freddie Chopin wrote:
On Sun, 2018-09-09 at 10:59 +0200, Thomas Kindler wrote:There are some things I'm not yet happy with: 1. Each lock takes about 80 bytesThis is easily solvable (; Just stop using FreeRTOS (; OK, but seriously. This is a consequence of FreeRTOS design, where "everything is a queue". Your mutex is in fact a queue with length zero, so it has dozens of useless member variables, which finally add up to ~80 bytes. In my opinion (which is of course biased and subjective), this design decision is extremely stupid. In other RTOSes (including distortos - the one I'm writing), the mutex is usually ~20-24 bytes long, so it's ~3-4x smaller, while having a lot more features (like selectable protocol or selectable type).
The 80 bytes for a mutex object are quite a lot. Even on RTEMS, which supports SMP systems and complex locking protocols, a recursive mutex needs just 24 bytes (32-bit target):
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=blob_plain;f=newlib/libc/sys/rtems/include/sys/lock.h;hb=HEADOn a uniprocessor RTOS two or three pointers and an integer should be enough to implement a recursive mutex with support for priority inheritance.
-- 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.huber@embedded-brains.de PGP : Public key available on request. Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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