minimal process configuration

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Nnamdi Kohn

minimal process configuration

Post by Nnamdi Kohn » Wed Oct 08, 2003 2:15 pm

Hello,

at QNX startup, QNX loads PHOTON and runs about 80 different threads. Does
anybody know how to distinguish which processes and threads are necessary
and which can me omitted to make the system react and run faster (for
realtime application)? I'd like to know the minimal thread configuration
possible and where to configure it at startup.

Thanks.

Nnamdi

Chris McKillop

Re: minimal process configuration

Post by Chris McKillop » Wed Oct 08, 2003 3:58 pm

Nnamdi Kohn <nnamdi.kohn@tu-bs.de> wrote:
Hello,

at QNX startup, QNX loads PHOTON and runs about 80 different threads. Does
anybody know how to distinguish which processes and threads are necessary
and which can me omitted to make the system react and run faster (for
realtime application)? I'd like to know the minimal thread configuration
possible and where to configure it at startup.
The number of threads doesn't effect system reaction time as much as the
number of threads at a given priority. The key to performing realtime
operations properly is to setup your realtime processes/threads with the
priorities required to ensure the system response that you need.

Most of what you are seeing is from Photon. Do you need Photon running? If
not try doing "touch /etc/system/config/nophoton", which will reduce the
number of processes that are run on startup.

chris

--
Chris McKillop <cdm@qnx.com> "The faster I go, the behinder I get."
Software Engineer, QSSL -- Lewis Carroll --
http://qnx.wox.org/

Nnamdi Kohn

Re: minimal process configuration

Post by Nnamdi Kohn » Thu Oct 09, 2003 7:53 am

"Chris McKillop" <cdm@qnx.com> schrieb im Newsbeitrag
news:bm1c75$7ns$1@nntp.qnx.com...
Nnamdi Kohn <nnamdi.kohn@tu-bs.de> wrote:
Hello,

at QNX startup, QNX loads PHOTON and runs about 80 different threads.
Does
anybody know how to distinguish which processes and threads are
necessary
and which can me omitted to make the system react and run faster (for
realtime application)? I'd like to know the minimal thread configuration
possible and where to configure it at startup.


The number of threads doesn't effect system reaction time as much as the
number of threads at a given priority. The key to performing realtime
operations properly is to setup your realtime processes/threads with the
priorities required to ensure the system response that you need.

Most of what you are seeing is from Photon. Do you need Photon running?
If
not try doing "touch /etc/system/config/nophoton", which will reduce the
number of processes that are run on startup.
Ok. What do these processes do that the system can be reduced of without
significant change? In how far is the system and photon affected by this
reduction?

Chris McKillop

Re: minimal process configuration

Post by Chris McKillop » Thu Oct 09, 2003 5:16 pm

Ok. What do these processes do that the system can be reduced of without
significant change? In how far is the system and photon affected by this
reduction?
One thing you can do is do a "pidin ar" and read the documentation for each
of the processes listed. Then you will know what it is doing. The two main
files that start everything up are /etc/system/sysinit for the basic system
without Photon, and /usr/bin/ph for the Photon environment.

chris


--
Chris McKillop <cdm@qnx.com> "The faster I go, the behinder I get."
Software Engineer, QSSL -- Lewis Carroll --
http://qnx.wox.org/

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