-----Original Message-----
From: Dalesio, Leo `Bob` [mailto:[email protected]]
Sent: Thursday, June 22, 2006 5:47 AM
To: Ralph Lange
Cc: Geoff Savage; Matthias Clausen; Andrew Johnson; EPICS core-talk;
Fritz Bartlett; Liyu, Andrei
Subject: RE: alarm hook
I'm an optimist about the general reuse of code. It's a habit. I
assume that we could make a minimum set of alarm consumers that would
be useful for all of us.
I would also like the dbPostEvent hook for archiving. I think that a
plant archiver that only wants data on occasion would prefer to have
it pushed out - rather than connect to 60000 channels. But there needs
to be a discussion on that.
-----Original Message-----
From: Ralph Lange [mailto:[email protected]]
Sent: Thursday, June 22, 2006 4:44 AM
To: Dalesio, Leo `Bob`
Cc: Geoff Savage; Matthias Clausen; Andrew Johnson; EPICS core-talk;
Fritz Bartlett; Liyu, Andrei
Subject: Re: alarm hook
I think the answers to all your questions highly depend on what A and
B are, which is the part not covered by the recent discussions.
Depending on the implementation of createMessage() A and B might be
Oracle servers, parts of the D0 event system, CMLOG servers .... with
all these different systems, I doubt there even will be a default
implementation for createMessage().
The alarm viewers are clients to these A and B servers, so even the
specs might differ depending on the system or installation.
Ralph
Dalesio, Leo `Bob` wrote:
Will A&B have a way to synchronize?
Is there thoughts of being able to serve the alarm information from
multiple sources to many clients?
Any specs on the alarm viewers?
Thanks,
Bob
-----Original Message-----
From: Geoff Savage [mailto:[email protected]]
Sent: Wednesday, June 21, 2006 10:36 PM
To: Matthias Clausen
Cc: Geoff Savage; Andrew Johnson; EPICS core-talk; Fritz Bartlett;
Liyu, Andrei
Subject: Re: alarm hook
Hi,
I am willing to accept the hook as proposed by Andrew. This is not
the
exact interface that I am currently using but it does provide the
information that I require. I will modify the FNAL interface to match
the proposed interface once the hook is in base.
It is not clear to me how an alarm hook function is registered in a
startup script. Can someone please provide an example that is
operating system independent?
From our (Matthias Clausen, Fritz Bartlett, Vladimir Sirotenko,
Geoff
Savage) discussions on Tuesday we developed a "generic" (but not
matching Andrei's interface) interface. I'll address Andrei's email
next. We propose to include the following "tools" for pushing alarms
from the server in a package separate from base. Here is a simple
chain showing all the pieces.
hook -> logAlarm -> queue -> sendToNetwork -> createMessage -> send
to A -> send to B (if send to A fails)
Here is a summary of our discussions on each piece with some of my
experiences included (and indicated).
1. We start with the generic hook as proposed by Andrew.
2. The hook function which a user will register is logAlarm(struct
dbCommon *prec, unsigned short sevr, unsigned short stat). Once this
function has determined that an alarm needs to be sent it gathers the
volatile data and inserts it into the alarm data queue. It should
also do something reasonable if the data can't be inserted in the
queue. It might simply keep track of the number of insertion failures
and report this number in a message once the queue has space.
Geoff - It should send messages on bad and good transitions. Care
should be taken when a record is successfully processed for the first
time as it transitions from an undefined (bad) state to a good state.
3. Users should be able to adjust the size of this queue to
accommodate
different numbers of records in the IOCs.
Geoff - There are more alarms during maintenance periods than during
run
times.
4. The sendToNetwork function is running as a separate thread
(vxworks
task) at a priority lower than the scan tasks but higher than channel
access. It waits for data to arrive in the alarm data queue. When
data arrives it passes the data to the createMessage routine.
5. The createMessage routine constructs a string message to be sent
across the network. To be more generic users should be able to define
their own createMessage routine. This allows users to use a different
message protocol within the push out framework.
Geoff - Using a string for messages removes byte ordering issues.
6. Send the message to server A. If sending the message to server A
fails then send the message to server B.
All the requirements are not included here. Hopefully DESY will
provide
more details as the project progresses.
Some other issues to consider -
a. From Jeff Hill - can we detect on a record by record basis when
an
alarm is not pushed out. I think this requires some study of the
common fields available to all records. This is on my to do list.
b. What will be in the data inserted into the alarm data queue?
This
should be all the volatile data needed in the network message to
decrease the time spent collecting the data.
c. What are the contents of the network message?
d. A generic server also needs to be provided.
Geoff
P.S. I need to sleep and will reply to Andrei's email in the morning.
On Jun 19, 2006, at 10:02 PM, Matthias Clausen wrote:
Hi Andrew,
I had a meeting today with Geoff, Fritz and Vladimir at Fermilab.
We discussed the implementation based on the proposed function call
and agreed on an implementation which should be as generic as
possible.
After Geoff's and Bernd Schoeneburg's vacation (next two weeks) we
will work on an implementation.
If Geoff does not see any unforeseen problems I would like to give
you a 'go' for the change in base.
Thanks for your help!
And - by the way - thanks for your clarification regarding Andrei's
mail.
Matthias
Andrew Johnson wrote:
Hi Matthias,
Matthias Clausen wrote:
in preparation for my meeting with Geoff at Fermilab I wand to
send you the proposed hook into base which Bernd Schoeneburg and
Bob already 'somehow' agreed on:
Here's Berns mail to Bob:
recGblResetAlarms is called in monitor() which is called in the
end of record processing just before recGblFwdLink and after
recGblGetTimeStamp. After calling recGblResetAlarms in monitor()
the value changes are checked (not interesting for us).
recGblResetAlarms checks for alarm changes and returns the fist
approach of the monitor mask, which is later used for postEvents.
postEvents can be called from anywhere like device support, snl,
subroutines, 'homebrew' records etc. I think recGblResetAlarms
is called in the monitor function of records only. So I think it
is the perfect place. Please check it and correct me if I am wrong.
The code could look like this (the end of recGblResetAlarms):
if(sevr!=nsev || stat!=nsta) {
++: logAlarm (pdbc, sevr, stat);
++: /* nsev and nsta are in pdbc->sevr and pdbc->stat */
ackt = pdbc->ackt; acks = pdbc->acks;
if(!ackt || nsev>=acks){
pdbc->acks=nsev;
db_post_events(pdbc,&pdbc->acks,DBE_VALUE);
}
}
return(mask);
}
My question:
Do you also agree with approach?
I agree with the location and arguments of the call, which I
believe are the same as Fermilab have been using.
And - what would be implemented in base for logAlarm ()?
This could be an empty function which just returns - or it could
be the 'real' thing where you'll have to check whether alarm
logging should be used at all.
The empty function could be replaced/ overloaded by the 'real'
function if you want to use putAlarm.
I think we just need a global pointer for the routine which will
be called if it's not NULL, so your code just sets it to hook in.
Here's my proposed patch:
Index: recGbl.h
==================================================================
= RCS file:
/net/phoebus/epicsmgr/cvsroot/epics/base/src/db/recGbl.h,v
retrieving revision 1.9
diff -u -b -r1.9 recGbl.h
--- recGbl.h 12 Feb 2003 21:22:23 -0000 1.9
+++ recGbl.h 19 Jun 2006 15:25:16 -0000
@@ -30,13 +30,23 @@
: FALSE\
)
+/* Structures needed for args */
-/* Global Record Support Routines*/ struct link; struct dbAddr;
struct dbr_alDouble; struct dbr_ctrlDouble; struct dbr_grDouble;
+struct dbCommon;
+
+/* Hook Routine */
+
+typedef void (*RECGBL_ALARM_HOOK_ROUTINE)(struct dbCommon *prec,
+ unsigned short sevr, unsigned short stat); extern
+RECGBL_ALARM_HOOK_ROUTINE recGblAlarmHook;
+
+/* Global Record Support Routines */
+
epicsShareFunc void epicsShareAPI recGblDbaddrError(
long status, struct dbAddr *paddr, char *pcaller_name);
epicsShareFunc void epicsShareAPI recGblRecordError(
Index: recGbl.c
==================================================================
= RCS file:
/net/phoebus/epicsmgr/cvsroot/epics/base/src/db/recGbl.c,v
retrieving revision 1.60.2.2
diff -u -b -r1.60.2.2 recGbl.c
--- recGbl.c 4 Nov 2004 19:21:08 -0000 1.60.2.2
+++ recGbl.c 19 Jun 2006 15:25:16 -0000
@@ -42,6 +42,10 @@
#include "recGbl.h"
+/* Hook Routines */
+
+RECGBL_ALARM_HOOK_ROUTINE recGblAlarmHook = NULL;
+
/* local routines */
static void getMaxRangeValues();
@@ -239,6 +243,7 @@
if(stat_mask)
db_post_events(pdbc,&pdbc->stat,stat_mask);
if(sevr!=nsev || stat!=nsta) {
+ if (recGblAlarmHook) (*recGblAlarmHook)(pdbc, sevr, stat);
ackt = pdbc->ackt; acks = pdbc->acks;
if(!ackt || nsev>=acks){
pdbc->acks=nsev;
If there is general agreement between DESY and FNAL about this,
I'll commit the change which will then appear in R3-14-9.
- Andrew
--
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Matthias Clausen Cryogenic Controls Group
(MKS-2)
phone: +49-40-8998-3256 Deutsches Elektronen
Synchrotron
fax: +49-40-8994-3256
Notkestr. 85
e-mail: [email protected] 22607
Hamburg
WWW-MKS2.desy.de
Germany
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