Hi,
just a little question:
if you have two threads in one process, one at prio 10 the other an prio
11 - now assume to be blocked.
when the prio-10-thread issues first a “pthread_mutex_lock( &myMUTEX) ;”
to a critical section and then within that critical section the
prio-11-thread becomes ready and issues also a “pthread_mutex_lock(
&myMutex ) ;” and has to stop at that “myMutex”, does the prio-10-thread
get its priority boosted up to 11 to prevent priority inversion ?
Jörg
=====================================================================
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: http://www.qnx.com ====
This is a simple one. Yes. QNX Neutrino implements priority
inheritence on mutexes.
-----Original Message-----
From: Joerg Kampmann [mailto:joerg.kampmann@ibk-consult.de]
Posted At: Tuesday, August 28, 2001 11:18 AM
Posted To: os
Conversation: Mutexlock and Prio Inversion ?
Subject: Mutexlock and Prio Inversion ?
Hi,
just a little question:
if you have two threads in one process, one at prio 10 the other an prio
11 - now assume to be blocked.
when the prio-10-thread issues first a “pthread_mutex_lock( &myMUTEX) ;”
to a critical section and then within that critical section the
prio-11-thread becomes ready and issues also a “pthread_mutex_lock(
&myMutex ) ;” and has to stop at that “myMutex”, does the prio-10-thread
get its priority boosted up to 11 to prevent priority inversion ?
Jörg
=====================================================================
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: http://www.qnx.com ====
Yes. That’s called ‘priority inheritance protocol’ in POSIX. QNX does
not do ‘priority ceiling’ though.
Joerg Kampmann wrote:
Hi,
just a little question:
if you have two threads in one process, one at prio 10 the other an prio
11 - now assume to be blocked.
when the prio-10-thread issues first a “pthread_mutex_lock( &myMUTEX) ;”
to a critical section and then within that critical section the
prio-11-thread becomes ready and issues also a “pthread_mutex_lock(
&myMutex ) ;” and has to stop at that “myMutex”, does the prio-10-thread
get its priority boosted up to 11 to prevent priority inversion ?
Jörg
=====================================================================
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: > http://www.qnx.com > ====
thanks, good to hear: Otherwise there would be a “hole in philosophy”
Jörg
Igor Kovalenko schrieb:
Yes. That’s called ‘priority inheritance protocol’ in POSIX. QNX does
not do ‘priority ceiling’ though.
Joerg Kampmann wrote:
Hi,
just a little question:
if you have two threads in one process, one at prio 10 the other an prio
11 - now assume to be blocked.
when the prio-10-thread issues first a “pthread_mutex_lock( &myMUTEX) ;”
to a critical section and then within that critical section the
prio-11-thread becomes ready and issues also a “pthread_mutex_lock(
&myMutex ) ;” and has to stop at that “myMutex”, does the prio-10-thread
get its priority boosted up to 11 to prevent priority inversion ?
Jörg
=====================================================================
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: > http://www.qnx.com > ====
–
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: http://www.qnx.com ====
the funny thing on it is: helpfiles to not mention it “expressis verbis”
- should be improved !
Jörg
Rennie Allen schrieb:
This is a simple one. Yes. QNX Neutrino implements priority
inheritence on mutexes.
-----Original Message-----
From: Joerg Kampmann [mailto:> joerg.kampmann@ibk-consult.de> ]
Posted At: Tuesday, August 28, 2001 11:18 AM
Posted To: os
Conversation: Mutexlock and Prio Inversion ?
Subject: Mutexlock and Prio Inversion ?
Hi,
just a little question:
if you have two threads in one process, one at prio 10 the other an prio
11 - now assume to be blocked.
when the prio-10-thread issues first a “pthread_mutex_lock( &myMUTEX) ;”
to a critical section and then within that critical section the
prio-11-thread becomes ready and issues also a “pthread_mutex_lock(
&myMutex ) ;” and has to stop at that “myMutex”, does the prio-10-thread
get its priority boosted up to 11 to prevent priority inversion ?
Jörg
=====================================================================
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: > http://www.qnx.com > ====
–
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: http://www.qnx.com ====
It is there. Check pthread_mutex_getprotocol. Standards are great, once
everyone knows them (until then, it simply seems that there is a lack of
documentation
-----Original Message-----
From: Joerg Kampmann [mailto:joerg.kampmann@ibk-consult.de]
Posted At: Tuesday, August 28, 2001 10:04 PM
Posted To: os
Conversation: Mutexlock and Prio Inversion ?
Subject: Re: Mutexlock and Prio Inversion ?
the funny thing on it is: helpfiles to not mention it “expressis verbis”
- should be improved !
Jörg
Rennie Allen schrieb:
This is a simple one. Yes. QNX Neutrino implements priority
inheritence on mutexes.
-----Original Message-----
From: Joerg Kampmann [mailto:> joerg.kampmann@ibk-consult.de> ]
Posted At: Tuesday, August 28, 2001 11:18 AM
Posted To: os
Conversation: Mutexlock and Prio Inversion ?
Subject: Mutexlock and Prio Inversion ?
Hi,
just a little question:
if you have two threads in one process, one at prio 10 the other an
prio
11 - now assume to be blocked.
when the prio-10-thread issues first a “pthread_mutex_lock( &myMUTEX)
;”
to a critical section and then within that critical section the
prio-11-thread becomes ready and issues also a “pthread_mutex_lock(
&myMutex ) ;” and has to stop at that “myMutex”, does the
prio-10-thread
get its priority boosted up to 11 to prevent priority inversion ?
Jörg
=====================================================================
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: > http://www.qnx.com > ====
–
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: http://www.qnx.com ====
well this is quite hidden - btw. but ok, I would have wished the
explanation at a more central point
In the meantime I made a little two-thread programme - with distinct
priorities per thread - and it worked - Super (nice to be seen when
the thread in question sleeps for a while and the other with higher prio
tries to mutex_lock … the prio is boosted) …
Jörg
Rennie Allen schrieb:
It is there. Check pthread_mutex_getprotocol. Standards are great, once
everyone knows them (until then, it simply seems that there is a lack of
documentation >
-----Original Message-----
From: Joerg Kampmann [mailto:> joerg.kampmann@ibk-consult.de> ]
Posted At: Tuesday, August 28, 2001 10:04 PM
Posted To: os
Conversation: Mutexlock and Prio Inversion ?
Subject: Re: Mutexlock and Prio Inversion ?
the funny thing on it is: helpfiles to not mention it “expressis verbis”
- should be improved ! >
Jörg
Rennie Allen schrieb:
This is a simple one. Yes. QNX Neutrino implements priority
inheritence on mutexes.
-----Original Message-----
From: Joerg Kampmann [mailto:> joerg.kampmann@ibk-consult.de> ]
Posted At: Tuesday, August 28, 2001 11:18 AM
Posted To: os
Conversation: Mutexlock and Prio Inversion ?
Subject: Mutexlock and Prio Inversion ?
Hi,
just a little question:
if you have two threads in one process, one at prio 10 the other an
prio
11 - now assume to be blocked.
when the prio-10-thread issues first a “pthread_mutex_lock( &myMUTEX)
;”
to a critical section and then within that critical section the
prio-11-thread becomes ready and issues also a “pthread_mutex_lock(
&myMutex ) ;” and has to stop at that “myMutex”, does the
prio-10-thread
get its priority boosted up to 11 to prevent priority inversion ?
Jörg
=====================================================================
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: > http://www.qnx.com > ====
–
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: > http://www.qnx.com > ====
–
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: http://www.qnx.com ====
however - it does not sleep faster !!! 
Joerg Kampmann schrieb:
well this is quite hidden - btw. but ok, I would have wished the
explanation at a more central point >
In the meantime I made a little two-thread programme - with distinct
priorities per thread - and it worked - Super (nice to be seen when
the thread in question sleeps for a while and the other with higher prio
tries to mutex_lock … the prio is boosted) …
Jörg
Rennie Allen schrieb:
It is there. Check pthread_mutex_getprotocol. Standards are great, once
everyone knows them (until then, it simply seems that there is a lack of
documentation >
-----Original Message-----
From: Joerg Kampmann [mailto:> joerg.kampmann@ibk-consult.de> ]
Posted At: Tuesday, August 28, 2001 10:04 PM
Posted To: os
Conversation: Mutexlock and Prio Inversion ?
Subject: Re: Mutexlock and Prio Inversion ?
the funny thing on it is: helpfiles to not mention it “expressis verbis”
- should be improved ! >
Jörg
Rennie Allen schrieb:
This is a simple one. Yes. QNX Neutrino implements priority
inheritence on mutexes.
-----Original Message-----
From: Joerg Kampmann [mailto:> joerg.kampmann@ibk-consult.de> ]
Posted At: Tuesday, August 28, 2001 11:18 AM
Posted To: os
Conversation: Mutexlock and Prio Inversion ?
Subject: Mutexlock and Prio Inversion ?
Hi,
just a little question:
if you have two threads in one process, one at prio 10 the other an
prio
11 - now assume to be blocked.
when the prio-10-thread issues first a “pthread_mutex_lock( &myMUTEX)
;”
to a critical section and then within that critical section the
prio-11-thread becomes ready and issues also a “pthread_mutex_lock(
&myMutex ) ;” and has to stop at that “myMutex”, does the
prio-10-thread
get its priority boosted up to 11 to prevent priority inversion ?
Jörg
=====================================================================
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: > http://www.qnx.com > ====
–
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: > http://www.qnx.com > ====
–
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: > http://www.qnx.com > ====
–
Dr. Jörg Kampmann - IBK-Consult for Real-Time and Embedded Systems
D-31228 Peine - Tel.:+49-177-276-3140 - Fax: +49-5171-13385
http://www.ibk-consult.de
===== QNX is the better Choice for Real-Time: http://www.qnx.com ====
Rennie Allen <RAllen@csical.com> wrote:
This is a simple one. Yes. QNX Neutrino implements priority
inheritence on mutexes.
But, an important note: QNX 6 does not do (can not do) priority
inheritance on semaphores. Mainly because there is no definition
of ownership for a semaphores as there is for a mutex.
So, if you are using semaphores as a mutex (say between processes),
then you risk a priority inversion problem.
QNX 6 does allow you to use mutexes between proceses, though, if you
set the process shared flag for the mutex. (Condition variables can
also be used between processes.)
-David
–
QNX Training Services
dagibbs@qnx.com
In article <3B8BF5B1.74336E22@motorola.com>,
Igor Kovalenko <Igor.Kovalenko@motorola.com> writes:
Yes. That’s called ‘priority inheritance protocol’ in POSIX. QNX does
not do ‘priority ceiling’ though.
qnx 6.2.0 adds support for PTHREAD_PRIO_PROTECT. Although the
implementation seems broken to me… I’m waiting for a comment
from my bug-report (sent yesterday - so I think there is
time left for an answer
David
–
The point of instantiation for a template used inside another template
and not instantiated previous to an instantiation of the enclosing
template is immediately before the point of instantiation of the
enclosing template.