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Force triggering of idle routine of a frontend

> We had a case where a detector produced electrostatic discharges which only lasted for a second or so
> and we were happy to detect this in spikes in the HV current. With measurements of only one per minute
> we would not have realized that so quicky.

For the T2K/ND280 TPC we implemented something similar. The TPC uses MicroMegas detector which sparks during 
normal operation. We asked Wiener/ISEG to implement a "spark counting mode" for us (and they did). In this mode,
high voltage over-current (a micromegas spark) sets a special flag (does not trip the high voltage). Our midas frontend
reads this flag at rate about 1/min, if flag is set, clears it, increments the software spark counter, reads the flag again,
if the flag is still set (failed to clear), it means this was not a normal spark but a high voltage breakdown
and the offending channel is shut down. I believe this mode is still part of the ISEG normal firmware.

Because the Wiener/ISEG interface uses SNMP to "read all data in one operation", the MIDAS "device driver" structure
was not useful, the readout was a simple loop, the readout frequency was easy to control, and indeed,
we read the high voltage with increased frequency during ramping. This was easy to implement because we
did not have to fight the MIDAS "device driver" framework.

If you want a similar solution, talk to the device, interpret the data, record values to odb and history, generate
midas events - all without hand holding from (arm wrestling with the rest of) midas - I recommend
the new tmfe.h/tmfe.cxx c++ frontend - see the two examples in midas/progs/fetest_tmfe.cxx
and fetest_tmfe_thread.cxx (single-threaded and multi-threaded).

K.O.

switch midas to c++ threads?

Hi, Stefan & co - now that midas is c++11 and c++11 comes with a threads library, should we 
switch midas to use the c++11 threads instead of pthreads? (Of course on Linux c++11 
threads are a layer on top of pthreads, the best I know).

This should remove the dependency on pthreads.h and use a more native implementation of 
threads on MacOS and Windows. (again, the best I can tell).

Of course this depends on c++11 threads having all the functions we need. Specifically, "lock 
with timeout" is useful to deal with "gah! everything stopped! what do I do!", a problem 
bedeviling midas in the early days (and still happens today!). Current midas kills everything 
after 5 minutes of deadlock - then the user knows how to restart everything and the developer 
has core dumps to look at. (to see which program/thread holds the lock and would not give it 
up).

Any thoughts on this?

K.O.

Compiling Midas in OS 10.15 Catalina

> Any luck with Midas in OS 10.15? 

Best I can tell, the problem is not in midas: pthread.h should be there, somewhere.

K.O.

Force triggering of idle routine of a frontend

You dirty hacks will probably work, but what you REALLY want is to read out your HV always as fast as possible, not only during run transitions or ramping. We had a case where a detector produced electrostatic discharges which only lasted for a second or so, and we were happy to detect this in spikes in the HV current. With measurements of only one per minute we would not have realized that so quicky.

Stefan

Pintaudi Giorgio wrote:

Dear Stefan,
Thank you for the advice. I will try to modify the driver as you say. As for the dynamical change of readout rate, basically you are telling me that is not achievable without dirty hacks like mine and it is better to find a way to avoid it.

Force triggering of idle routine of a frontend

Stefan Ritt wrote:

Dear Giorgio,

ok, now I'm slowly getting your point.

Dynamically changing the slow control readout rate is possible with your modification, but I consider this badd practice.

You mentioned the case of your HV over a quirky serial line. I had the same some years ago. Rather than reducing the readout rate to reduce the number of errors, I modified my device driver. If the connection is broken, the driver tries silently to reconnect. Only if the reconnect fails for more than a given period (like 1 min), then an error is produced. Otherwise the driver reads as fast as possible. Imagine you have some instabilities in your HV, which only last for a few seconds. If you read only once per minute, you might miss that. We worked hard to make the slow control system multi-threaded, so a slow many-times-retrying-to-reconnect driver does not slow any other equipment. On the other hand, if the re-connect fails for a minute, then you know that your HV unit really has a problem the shifter should follow up.

Best,
Stefan

Force triggering of idle routine of a frontend

Compiling Midas in OS 10.15 Catalina

> 
> Ok, in this case, I will update my office mac mini to 10.15.
> 
> K.O.


Hi Konstantin, 

Any luck with Midas in OS 10.15? 
I have downgraded to Xcode 10.2.1 as suggested in the post linked in my first post, without any luck, I keep getting the same pthead.h error. 
MY gcc uses the 10.15 sdk despite having v 10.2.1 for Xcode and command line tools 

Darrens-Mac-mini:~ betacage$ gcc --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-
dir=/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/include/c++/4.2.1
Apple LLVM version 10.0.1 (clang-1001.0.46.4)
Target: x86_64-apple-darwin19.3.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin


and that is where I suspect the problem is. Will keep investigating next week. Thanks for your help.

Berta

Compiling Midas in OS 10.15 Catalina

> > > I have updated our daq computer to the latest OS 10.15 ...
> > 
> > FWIW, I do not have macos 10.15. I have 10.13 at home and 10.14 in the office. Maybe Stefan has it?
> 
> No, I'm stuck with 10.14 due to the current lack of 64-bit support of some programs.
> 

Ok, in this case, I will update my office mac mini to 10.15.

K.O.

Force triggering of idle routine of a frontend

Dear Stefan,
thank you very much for the clarification. I knew about the DF_XXX flags and I am making good use of them in all my frontends. Anyway, what I really needed was to change the readout rate depending on the run status (in particular DF_RUNNING or DF_TRANSITION).

Moreover, currently, I am not using the MIDAS events framework at all. For the real DAQ, we have our way of acquiring and saving the raw data using the Pyrame software. For the slow control devices, we just use the information that MIDAS automatically saves in the history files .hst (very handy). But I am going to use the MIDAS events at some point in the future, so your explanation is very welcome.

However, I was able to solve my problem by slightly modifying the mfe.cxx file in this way:

@@ -411,6 +411,17 @@ static INT register_equipment(void)
             ss_sleep(3000);
             return 0;
          }
+#ifdef WAGASCI_OPEN_ODB_HOTLINK
+         status = db_open_record(hDB, hKey, eq_info, sizeof(EQUIPMENT), MODE_READ,
+                                 nullptr, nullptr);
+         if (status != DB_SUCCESS) {
+            printf("ERROR: Cannot open hotlink with equipment record \"%s\", db_open_record() status %d\n",
+                   str, status);
+            cm_disconnect_experiment();
+            ss_sleep(3000);
+            return 0;
+         }
+#endif
       } else if (status == DB_STRUCT_MISMATCH) {
          cm_msg(MINFO, "register_equipment", "Correcting \"%s\", db_check_record() status %d", str, status);
          db_create_record(hDB, 0, str, EQUIPMENT_COMMON_STR);

I was quite surprised that I could get things done by just opening a hotlink to the EQUIPMENT eq_info struct. That way I can change dynamically the readout rate (the rate at which the idle routine of a slow device frontend is called is tuned by the "/Equipment/<frontend name>/Common/Event Limit" variable). I change this variable temporarily during a transition to increase the reading rate. I have done some testing and it seems to have no collateral effect.
There is only one caveat.

Every change to the equipment "/Equipment/<frontend name>/Common" is instantaneously applied (and might crash the frontend?)

Just to give you an example of a situation where all of this might be useful, think about the ramping-up of the high voltage applied to APD or MPPC. When ramping up from 0 to X volts, you want to read out the voltage and current frequently (let's say once every second) to check for overcurrent and stuff. But as soon as the voltage is up and stable you do not need to monitor it every second and a reading every minute might be more than enough. In our case, the HV power supplies are connected through a serial bus (a nightmare to get it working) and once in a while, we have a transitory connection error. If we kept the reading rate very high continuously the log would be flooded with these innocuous errors (but every new shifter would panic every time he/she notices them). Anyway, this is just an example.

Stefan Ritt wrote:

It is important to note that slow control readout and sending of midas events are two separate things. Readout is done as fast as possible, even multi-threaded if selected. On fast devices this can be 100 Hz readout rate and even more. This data is stored in an internal buffer. When one of the values changes by more than the update threshold, then the ODB gets updated. The midas events are composed from this internal buffer when a new event has to be sent. This is typically periodic (like every 10 seconds or so), or during run transitions. If you specify this in the equipment list with the RO_xxx flags. If you want an event at the begin-of-run, just add there RO_BOR. It should be noted however that this then creates and event during BOR from the last values in the internal buffer, which - depending on the readout speed - can be a few ms "old". I would recommend that you test the readout speed of your variables and then check if this delay is acceptable.

Best,
Stefan

Pintaudi Giorgio wrote:

Hello!
As you know, the generic MIDAS frontend has a class driver, device driver, bus driver
structure. Assuming a slow device frontend, its class driver should have a routine of type

INT idle (EQUIPMENT * pequipment)

This routine is called with a rate controlled by the
"/Equipment/<frontend name>/Common/Event limit" parameter.
The idle routine usually reads one channel of the frontend and stores the results
in the "/Equipment/<frontend name>/Variables" ODB folder.

My question is: it is possible to force (from the code) the frontend to call the idle routine at a
certain point. This is because I need to update the "/Equipment/<frontend name>/Variables"
variables inside the "begin_of_run" routine, at a very specific time.

One dirty solution would be to increase a lot the reading rate ... but I need this
increased reading rate only during the run start while I need a low reading rate
during the run. So the question: is it possible to increase and decrease the reading
rate (event limit) of a frontend without stopping and restarting it?

If you need more info, please let me know.
Thank you
Giorgio

Compiling Midas in OS 10.15 Catalina

> > I have updated our daq computer to the latest OS 10.15 ...
> 
> FWIW, I do not have macos 10.15. I have 10.13 at home and 10.14 in the office. Maybe Stefan has it?

No, I'm stuck with 10.14 due to the current lack of 64-bit support of some programs.

I would try KOs proposal to do a "xcode-select --install".

Stefan

Force triggering of idle routine of a frontend

Pintaudi Giorgio wrote:

Hello!
As you know, the generic MIDAS frontend has a class driver, device driver, bus driver
structure. Assuming a slow device frontend, its class driver should have a routine of type

INT idle (EQUIPMENT * pequipment)

Force triggering of idle routine of a frontend

Dear Konstantin,
thank you very much for the explanation. I already have an idea of how to solve my problem by bypassing the class driver altogether or by slightly modifying the mfe.cxx frontend.
But either way is not very elegant. If there was a way to do what I need easily and without writing much code, I would obviously choose that.
So let us wait for Stefan opinion!
Thanks again
Giorgio

Quote:

> Hi, Giorgio - I think you encountered a fundamental problem with what to do at the begin of
> run. There are two ways of thinking about it.
>
> Some experiments want to start the run as quickly as possible, so they do not want
> begin_of_run() to do too much stuff.
>
> Other experiments want to record all the current settings and conditions before starting a
> run, their begin_of_run() will read all the slow controls, interrogate all the power supplies,
> read all the voltages, temperatures, pressures, etc. By necessity this will slow down the
> starting of the run quite significantly.
>
> The best I understand the midas class driver structure, it is more geared for the first case -
> fast starting of runs.
>
> The thinking behind this choice considers the nature of most slow control data in typical
> physics experiments:
> - if the data does not change quickly (say, room temperature, atmospheric pressure, etc),
> and you read it say every 1 minute, then you do not need to read it again at begin run time -
> the 1 minute old measurement is still good enough - nothing changed much since then
> - if the opposite is true, the data changes wildly (i.e. detector high voltage current goes up
> and down in response to the quickly changing beam current), measuring it at the start of
> the run does us no good - by the time the first event comes around, it has already changed
> completely.
>
> Hopefully Stefan can help you with your specific problem, he has better understanding of
> the midas class drivers.
>
>
> K.O.

support for mbedtls - get an open ssl error while trying to compile Midas

> I only work on this project from Tuesday to Thursdays.

No problem. No hurry.

> I have run " make cmake" instead of "cd build; cmake" and this is the output regarding mhttpd: ...

There should be also a line where mhttpd.cxx is compiled into mhttpd.o, we need to see what compiler
flags are used - I suspect the compiler uses header files from /usr/local/include while the linker
is using libraries from /usr/lib, a mismatch.

To save time, please attach the full output of "make cmake". There may be something else I want to see there.

If you do not use the mhttpd built-in https support (for best security I recommend using https from the apache httpd password protected https proxy),
then it is perfectly fine to build midas with NO_SSL=1.

K.O.

MIDAS tested with MariaDB?

> We're using the History Logger MIDAS feature and writing to mySQL tables, but 
> in some cases have run into issues installing mySQL on centos7 systems.
> 
> Has anyone ever tried running this MIDAS feature with MariaDB rather than 
> mySQL?

The best I can tell, MariaDB is *the* mysql. "the other thing" is an abandonware fork.

I personally at this moment do not run any daq stations with mysql logging, and I accidentally
removed all the 25 versions and flavours of mysql from my home laptop, so if there
is any problems with mysql, please holler, and I will reinstall mysql (ahem, mariadb) and restore
my ability to test midas against it.

As a connected question, is there any need to have postgres support in midas as well?

K.O.

Force triggering of idle routine of a frontend

Hi, Giorgio - I think you encountered a fundamental problem with what to do at the begin of 
run. There are two ways of thinking about it.

Some experiments want to start the run as quickly as possible, so they do not want 
begin_of_run() to do too much stuff.

Other experiments want to record all the current settings and conditions before starting a 
run, their begin_of_run() will read all the slow controls, interrogate all the power supplies, 
read all the voltages, temperatures, pressures, etc. By necessity this will slow down the 
starting of the run quite significantly.

The best I understand the midas class driver structure, it is more geared for the first case - 
fast starting of runs.

The thinking behind this choice considers the nature of most slow control data in typical 
physics experiments:
- if the data does not change quickly (say, room temperature, atmospheric pressure, etc), 
and you read it say every 1 minute, then you do not need to read it again at begin run time - 
the 1 minute old measurement is still good enough - nothing changed much since then
- if the opposite is true, the data changes wildly (i.e. detector high voltage current goes up 
and down in response to the quickly changing beam current), measuring it at the start of 
the run does us no good - by the time the first event comes around, it has already changed 
completely.

Hopefully Stefan can help you with your specific problem, he has better understanding of 
the midas class drivers.


K.O.


[quote="Pintaudi Giorgio"]Hello!
As you know, the generic MIDAS frontend has a class driver, device driver, bus driver
structure. Assuming a slow device frontend, its class driver should have a routine of type   
[CODE]INT idle (EQUIPMENT * pequipment)[/CODE]
This routine is called with a rate controlled by the 
"[I]/Equipment/<frontend name>/Common/Event limit[/I]" parameter.
The idle routine usually reads one channel of the frontend and stores the results
in the "[I]/Equipment/<frontend name>/Variables[/I]" ODB folder.

[B]My question is: it is possible to force (from the code) the frontend to call the idle routine 
at a 
certain point. This is because I need to update the "[I]/Equipment/<frontend 
name>/Variables[/I]"
variables inside the "[I]begin_of_run[/I]" routine, at a very specific time.[/B]

One dirty solution would be to increase a lot the reading rate ... but I need this
increased reading rate only during the run start while I need a low reading rate
during the run. So the question: is it possible to increase and decrease the reading
rate (event limit) of a frontend without stopping and restarting it?

If you need more info, please let me know.
Thank you
Giorgio[/quote]

Compiling Midas in OS 10.15 Catalina

> I have updated our daq computer to the latest OS 10.15 ...

FWIW, I do not have macos 10.15. I have 10.13 at home and 10.14 in the office. Maybe Stefan has it?

> In file included from /Users/betacage/packages/midas/include/mfe.h:13:
> /Users/betacage/packages/midas/include/midas.h:159:10: fatal error: 'pthread.h' file not found
> #include <pthread.h>
>          ^~~~~~~~~~~

Hmm... pthread.h should be there, I do not see any notice of it's removal in macos.

So I suspect a mis-installation of c++ compilers. In the past we had problems with this,
in addition to installing Xcode from the app store, one most install some missing stuff
manually ("XCode command line tools"), if I have it right, the command is "xcode-select --install".

If you figure out how to build it, I think midas will work just fine on the latest macos.

K.O.

Compiling Midas in OS 10.15 Catalina

Hi all, 

I have updated our daq computer to the latest OS 10.15 with the idea that then I will get all our daq 
programs running and will not need to update again in years to come. 
But now I am running unto even more problems trying to compile Midas. 
OS 10.15.3, Xcode 11.3 with commad line tools 

Darrens-Mac-mini:~ betacage$ cd packages/midas/build/
Darrens-Mac-mini:build betacage$ cmake .. 
-- MIDAS: cmake version: 3.16.3
-- The C compiler identification is AppleClang 11.0.0.11000033
-- The CXX compiler identification is AppleClang 11.0.0.11000033
-- Check for working C compiler: /Library/Developer/CommandLineTools/usr/bin/cc
-- Check for working C compiler: /Library/Developer/CommandLineTools/usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /Library/Developer/CommandLineTools/usr/bin/c++
-- Check for working CXX compiler: /Library/Developer/CommandLineTools/usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- MIDAS: CMAKE_INSTALL_PREFIX: /Users/betacage/packages/midas
-- MIDAS: Found ROOT version 6.18/04
-- Found ZLIB: /usr/lib/libz.dylib  
-- MIDAS: Found ZLIB version 
-- MIDAS: Found OpenSSL version 1.1.1d
-- MIDAS: MySQL not found
-- MIDAS: ODBC not found
-- MIDAS: SQLITE not found
-- MIDAS: nvidia-smi not found
-- Found Git: /usr/bin/git (found version "2.21.0 (Apple Git-122.2)") 
-- MIDAS example/experiment: MIDAS in-tree-build
-- MIDAS: Found ZLIB version 
-- MIDAS example/experiment: Found ROOT version 6.18/04
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/betacage/packages/midas/build
Darrens-Mac-mini:build betacage$ make install
[  1%] Building CXX object CMakeFiles/mfeo.dir/src/mfe.cxx.o
In file included from /Users/betacage/packages/midas/src/mfe.cxx:15:
In file included from /Users/betacage/packages/midas/include/mfe.h:13:
/Users/betacage/packages/midas/include/midas.h:159:10: fatal error: 'pthread.h' file not found
#include <pthread.h>
         ^~~~~~~~~~~
1 error generated.
make[2]: *** [CMakeFiles/mfeo.dir/src/mfe.cxx.o] Error 1
make[1]: *** [CMakeFiles/mfeo.dir/all] Error 2


I guess that I am maybe the first one trying to install MIDAS in this OS, so I am willing to help as much as I 
can with getting this going. I have found a solution to this by downgrading Xcode to version 10 
https://stackoverflow.com/questions/58524715/failing-to-compile-a-c-application-under-macos-catalina-10-15
If you don't have other solutions I will try to do that tomorrow.

Thanks 

Berta

Force triggering of idle routine of a frontend

Hello!
As you know, the generic MIDAS frontend has a class driver, device driver, bus driver
structure. Assuming a slow device frontend, its class driver should have a routine of type

INT idle (EQUIPMENT * pequipment)

MIDAS tested with MariaDB?

> We're using the History Logger MIDAS feature and writing to mySQL tables, but 
> in some cases have run into issues installing mySQL on centos7 systems.
> 
> Has anyone ever tried running this MIDAS feature with MariaDB rather than 
> mySQL?

Hi

I've used MIDAS Logger feature with MariaDB and had no issue thus far .

MIDAS tested with MariaDB?

I have used the mySQL runlog with MariaDB before. I don't recall any problems on Fedora Core 29 or so (after MIDAS compiled).

Quote:

MariaDB intended to maintain high compatibility with MySQL, ensuring a drop-in replacement capability with library binary parity and exact matching with MySQL APIs and commands.

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