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Forum Topic - Overall Limit of mq sizes: (3 Items)

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Gunter Geigemueller

04/27/2010 7:46 AM

post52864

Hello,

is there a limit of the accumulated size of all messages queues created with alternative mq? From my understanding, this
 would be remaining amount of kernel memory, which is on an x86 0.5GB - what_the_kernel_needs. Correct?

Thanks,
Albrecht

Steve Reid(deleted)

04/27/2010 10:56 AM

post52905

RE: Overall Limit of mq sizes

There's a section on the limits for message queues in the Neutrino
User's Guide:

 
http://www.qnx.com/developers/docs/6.4.1/neutrino/user_guide/limits.html
#Mqueue

Steve Reid (stever@qnx.com)
Technical Editor
QNX Software Systems 
 

> -----Original Message-----
> From: Gunter Geigemueller [mailto:community-noreply@qnx.com] 
> Sent: Tuesday, April 27, 2010 7:47 AM
> To: momentics-community
> Subject: Overall Limit of mq sizes
> 
> Hello,
> 
> is there a limit of the accumulated size of all messages 
> queues created with alternative mq? From my understanding, 
> this would be remaining amount of kernel memory, which is on 
> an x86 0.5GB - what_the_kernel_needs. Correct?
> 
> Thanks,
> Albrecht
> 
> 
> 
> _______________________________________________
> 
> QNX Momentics Community Support
> http://community.qnx.com/sf/go/post52864
> 
>

Gunter Geigemueller

04/28/2010 4:26 AM

post52968

Re: RE: Overall Limit of mq sizes

We did read this before. As far as we understand it, these numbers are just the defaults for an individual message queue
 that are used if I do not pass an mq_attr struct when creating the queue. I can override these values in software by 
setting appropriate values in struct mq_attr.

My question was if there is a limit on the sum of all message queues created, e.g.:

Queue 1: 1024 entries @ 8KB
Queue 2: 2000 entries @ 2KB
Queue 3: 1000 entries @ 4KB

That gives a total usage of 1024*8+2000*2+1000*4=16192KB +  any associated overhead.

-Albrecht

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