Experimental Physics and
Industrial Control System

"Bertrand H.J. Biritz" <[email protected]> · Tue, 14 Nov 2006 12:38:56 -0800

Hi Albert,
thank you very much for the updated devSNMP :)
I compiled it and the IOC works - although I need to use "make clean
uninstall install", or else I get a segmentation fault when loading
the db.
Bertrand

On Nov 14, 2006, at 9:32 AM, Kagarmanov, Albert wrote:
 Hi Andrew,

Yes, it's clear that using

epicsThreadGetStackSize(epicsThreadStackBig) is much more universal
than

pure constants as 10000 or 132096.

Small constant can cause warning (like we at DESY had before in our

SL2.6/R3.14.7.2, when we used stackSize=10000) or even error (like you

wrote).

Thank you for advice!

I've already re-compile, test and add this your changing in our

DESY devSNMP download page

(http://www-mks2.desy.de/content/e4/e40/e41/e12212/)
Best regards,
Albert
-----Original Message-----
From: Andrew Johnson [mailto:[email protected]]
Sent: Tuesday, November 14, 2006 4:58 PM
To: Kagarmanov, Albert
Cc: Bertrand H.J. Biritz; [email protected]
Subject: Re: devSNMP: Thread error?

Albert,
Kagarmanov, Albert wrote:

 This is not a real error, it's warning from

pthread_attr_setstacksize

system-call, which invoked in devSnmp.c in function
		int epicsSnmpInit(int param)

Actually it is an error, in the epicsSnmpInit() code.
It looks like 10000 stack-size is small enough for your Linux (See
http://docs.sun.com/app/docs/doc/816-5137/6mba5vpja?a=view

for detail)

We've changed this size till 128K as it recommended in
$EPICS/base/documentation/RELEASE_NOTES.html and don't have this
warning. See our http://www-mks2.desy.de/content/e4/e40/e41/e12212/
for detail.

The stackSize parameter to the epicsThreadCreate() call should
not be a
number as the sizes needed can be different on different
architectures.
 The epicsSnmpInit() function should be passing
epicsThreadGetStackSize() one of three values epicsThreadStackSmall,
epicsThreadStackMedium or epicsThreadStackBig according to how much
stack the thread is expected to need, and using the return value from
epicsThreadGetStackSize() as the parameter to
epicsThreadCreate(). As an
example, here's an excerpt from base/src/db/callback.c:
    callbackTaskId[ind] = epicsThreadCreate(taskName, priority,
        epicsThreadGetStackSize(epicsThreadStackBig),
        (EPICSTHREADFUNC)callbackTask, &priorityValue[ind]);
By using this approach, the problem should not arise in the
future as a
new architecture with a bigger or smaller stack requirement that gets
added to Base can adjust the absolute amount of memory
allocated to the
three sizes.
My appologies if the wording in RELEASE_NOTES.html was confusing, and
the Application Developers Guide entry for epicsThreadCreate()
probably
didn't help much either; I have just revised both documents.
- Andrew
--
There is considerable overlap between the intelligence of the
smartest bears and the dumbest tourists -- Yosemite National
Park Ranger

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System