Back Midas Rome Roody Rootana
  Midas DAQ System, Page 118 of 122  Not logged in ELOG logo
New entries since:Wed Dec 31 16:00:00 1969
ID Date Authorup Topic Subject
  Draft   15 Jan 2016 Tom StuttardSuggestion64 bit bank type
> > I've seen that a similar question has been asked in 2011 but I'll ask again in 
> > case there are any updates. Is there any way to write 64-bit data words to MIDAS 
> > banks (other than breaking them up in to two 32-bit words, such as 2 DWORDs) 
> > currently? And if not, is there any plan to introduce this feature in the future?
> 
> There is no "breaking them up" as such, you can treat a midas bank as a char* array
> and store arbitrary data inside. In this sense, "there is no need" for a special 64-bit bank type.
> 
> For endian-ness conversion (if such things still matter, big-endian PPC CPUs still exist), single 64-bit 
> word converts the same as two 32-bit words, so here also "there is no need", once can use banks of 
> DWORD with equal effect.
> 
> The above applies equally to 64-bit integers and 64-bit double-precision IEEE-754 floating point 
> numbers.
> 
> But specifically for 64-bit values, such as float64, there is a big gotcha.
> 
> The MIDAS banks structure goes to great lengths to make sure each data type is correctly aligned,
> and gets it exactly wrong for 64-bit quantities - all because the bank header is three 32-bit words.
> 
> bankhheader1
> bh2
> bh3
> bankdata1 <--- misaligned
> ...
> bankdataN
> bh1
> bh2
> bh3
> banddata1 <--- aligned
> ... etc
> 
> So we could introduce QWORD banks today, but inside the midas file, they will be misaligned defeating 
> the only purpose of adding them.
> 
> I guess the misalignement could be cured by adding dummy words, dummy banks, dummy bank 
> headers, etc.
> 
> I figure this problem dates all the way bank where alignement to 16-bits was just getting important. 
> Today, in the VME word, I have to align things on 128-bit boundaries (for 2eSST 2x2 DWORD transfers).
> 
> So back to your question, what advantage do you see in using a QWORD bank instead of putting the 
> same data in a DWORD bank?
> 
> K.O.
  1155   19 Jan 2016 Tom StuttardSuggestion64 bit bank type
> > I've seen that a similar question has been asked in 2011 but I'll ask again in 
> > case there are any updates. Is there any way to write 64-bit data words to MIDAS 
> > banks (other than breaking them up in to two 32-bit words, such as 2 DWORDs) 
> > currently? And if not, is there any plan to introduce this feature in the future?
> 
> There is no "breaking them up" as such, you can treat a midas bank as a char* array
> and store arbitrary data inside. In this sense, "there is no need" for a special 64-bit bank type.
> 
> For endian-ness conversion (if such things still matter, big-endian PPC CPUs still exist), single 64-bit 
> word converts the same as two 32-bit words, so here also "there is no need", once can use banks of 
> DWORD with equal effect.
> 
> The above applies equally to 64-bit integers and 64-bit double-precision IEEE-754 floating point 
> numbers.
> 
> But specifically for 64-bit values, such as float64, there is a big gotcha.
> 
> The MIDAS banks structure goes to great lengths to make sure each data type is correctly aligned,
> and gets it exactly wrong for 64-bit quantities - all because the bank header is three 32-bit words.
> 
> bankhheader1
> bh2
> bh3
> bankdata1 <--- misaligned
> ...
> bankdataN
> bh1
> bh2
> bh3
> banddata1 <--- aligned
> ... etc
> 
> So we could introduce QWORD banks today, but inside the midas file, they will be misaligned defeating 
> the only purpose of adding them.
> 
> I guess the misalignement could be cured by adding dummy words, dummy banks, dummy bank 
> headers, etc.
> 
> I figure this problem dates all the way bank where alignement to 16-bits was just getting important. 
> Today, in the VME word, I have to align things on 128-bit boundaries (for 2eSST 2x2 DWORD transfers).
> 
> So back to your question, what advantage do you see in using a QWORD bank instead of putting the 
> same data in a DWORD bank?
> 
> K.O.


Thanks very much for your reply. I have implemented your suggestion of treating the 64-bit array as a 32-bit 
array for the bank write/read and this solution is working for me.

Thanks again for your help.
  846   14 Dec 2012 Vinzenz BildsteinSuggestionMidas + Elog with SSL
I've been trying to set up midas to create an automatic elog entry at the end of
each run and I've run into a problem. I've setup an elog on our server which
uses SSL and it seems that the melog provided by midas to create logbook entries
doesn't know any SSL.

My solution to this was to copy the crypt.c from the elog package to the
computer running midas and changed melog.c and the makefile to use SSL if a flag
-s is used. Does this seem like a sensible solution or did I oversee the obvious
and/or right way to do this?
  848   17 Dec 2012 Vinzenz BildsteinSuggestionMidas + Elog with SSL
> > I've been trying to set up midas to create an automatic elog entry at the end of
> > each run and I've run into a problem. I've setup an elog on our server which
> > uses SSL and it seems that the melog provided by midas to create logbook entries
> > doesn't know any SSL.
> > 
> > My solution to this was to copy the crypt.c from the elog package to the
> > computer running midas and changed melog.c and the makefile to use SSL if a flag
> > -s is used. Does this seem like a sensible solution or did I oversee the obvious
> > and/or right way to do this?
> 
> Indeed melog.c is an old version of the elog.c utility in the elog package, which has not been maintained since a 
> long time. Can't you just use the recent elog.c utility from the elog package?

Well, that's essentially what I did, I just didn't want to install the whole elog package on the midas server. Whether
the utility is called elog or melog doesn't really matter. I just wanted to make sure that this is the right way to do
it. 

Thanks!
  1597   08 Jul 2019 Vinzenz BildsteinBug ReportFrontend killed at stop of run
I wrote a c++ frontend to read data from CAEN VX1730 digitizers which is used in
parallel with the GRIFFIN frontend to read out DESCANT.

After a long overnight run to check that the frontend runs smoothly for a longer
time, I stopped the run and the frontend was killed by midas. I am not sure why
this happened, as the end_of_run function returned successfully (at least the
print statement right before "return SUCCESS;" appeared right away). So
something else must have timed-out and caused it to be killed, I guess?

Any suggestions on where to look to find out what causes this?

Thanks in advance for your help!
  1601   08 Jul 2019 Vinzenz BildsteinBug ReportFrontend killed at stop of run
> run the frontend inside gdb and post the stack trace after the crash?
> 
> if there is no crash (the program is stopped by exit()), you may need
> to set a breakpoint in exit() or _exit() (not sure what it's latest name is)
> then with luck your stack trace will show who/what called it from where.
> 

If I remember correctly from the last time I tried that, it doesn't use the exit
function but gdb just reports that the program was terminated and no longer exists. I
can't set a breakpoint on SIGKILL as the point of SIGKILL is to kill the program and
gdb can't set a break at that point afaik.
  1603   08 Jul 2019 Vinzenz BildsteinBug ReportFrontend killed at stop of run
> > > run the frontend inside gdb and post the stack trace after the crash?
> > > 
> > > if there is no crash (the program is stopped by exit()), you may need
> > > to set a breakpoint in exit() or _exit() (not sure what it's latest name is)
> > > then with luck your stack trace will show who/what called it from where.
> > > 
> > 
> > If I remember correctly from the last time I tried that, it doesn't use the exit
> > function but gdb just reports that the program was terminated and no longer exists. I
> > can't set a breakpoint on SIGKILL as the point of SIGKILL is to kill the program and
> > gdb can't set a break at that point afaik.
> 
> For SIGKILL, my gdb reports "Program terminated with signal SIGKILL, Killed." and there is no stack 
> trace. Is this what you see?

Yes, that is exactly what I remember seeing.

> 
> If your program stops "normally", not from receiving some signal, set breakpoints on "exit" and 
> "_exit".
> 
> The normal stop sequence is to call exit(), which runs all the atexit() functions (the midas atexit() 
> function prints the message about "cm_disconnect_experiment not called at end of program") and 
> calls _exit() to stop the program.
> 
> So if you see the midas message "cm_disconnect_experiment not called at end of program", it is a 
> good indication that somebody (not mfe.c) called exit() on you. A breakpoint on "exit" should catch 
> who does it.
> 
> Good luck,
> K.O.

So far I haven't seen the issue with the message "cm_disconnect_experiment not called at end of program"
again. Now I just have to restart the frontend after the run has (failed?) to stop. After restarting the
frontend everything seems to work again. 

I haven't been writing data while doing these tests, so I can't say if there is any data missing or if the
runs were actually stopped properly (with a second dump of the ODB at the end).
  1605   08 Jul 2019 Vinzenz BildsteinBug ReportFrontend killed at stop of run
> > > 
> > > For SIGKILL, my gdb reports "Program terminated with signal SIGKILL, Killed." and there is no stack 
> > > trace. Is this what you see?
> > 
> > Yes, that is exactly what I remember seeing.
> > 
> 
> Where would a SIGKILL come from?!?
> 
> Look in the syslog (/var/log/messages). If the program was killed by the linux kernel, it would be logged there,
> the usual cause is the machine runs out of memory and programs are killed by the OOM killer, this is logged
> into the syslog, always.
> 
> MIDAS also can issue a SIGKILL sometimes, again this is always logged in midas.log. see src/midas.c, search for SIGKILL to see 
> the exact messages printed before it is sent out.
> 
> K.O.

I haven't been able to reproduce the error from the overnight run so far. I will try and leave this running in gdb overnight to see
if I can get that error again. 
  1608   10 Jul 2019 Vinzenz BildsteinBug ReportFrontend killed at stop of run
> > > > 
> > > > For SIGKILL, my gdb reports "Program terminated with signal SIGKILL, Killed." and there is no stack 
> > > > trace. Is this what you see?
> > > 
> > > Yes, that is exactly what I remember seeing.
> > > 
> > 
> > Where would a SIGKILL come from?!?
> > 
> > Look in the syslog (/var/log/messages). If the program was killed by the linux kernel, it would be logged there,
> > the usual cause is the machine runs out of memory and programs are killed by the OOM killer, this is logged
> > into the syslog, always.
> > 
> > MIDAS also can issue a SIGKILL sometimes, again this is always logged in midas.log. see src/midas.c, search for SIGKILL to see 
> > the exact messages printed before it is sent out.
> > 
> > K.O.
> 
> I haven't been able to reproduce the error from the overnight run so far. I will try and leave this running in gdb overnight to see
> if I can get that error again. 

I was able to reproduce the error after an overnight run. gdb reported that the program received a SIGKILL, but no sign of it in 
/var/log/messages. I've tried finding a current midas.log file, but it seems we don't have one? The most recent one was last updated 
on May 24th this year.
  1613   11 Jul 2019 Vinzenz BildsteinBug ReportFrontend killed at stop of run
> > ... finding a current midas.log file
>
> On the "help" page, see "midas.log".
>
> Same information is in ODB, the midas log file name is concatenation of "/Logger/Data dir" and "message file".
>
> K.O.

Sorry, should have found that myself ...

Anyway, the output from midas is
Tue Jul  9 07:24:06 2019 [mhttpd,INFO] Run #13456 started
Wed Jul 10 06:23:58 2019 [mhttpd,ERROR] [system.c:4580:ss_recv_net_command,ERROR] timeout receiving network 
command header
Wed Jul 10 06:23:58 2019 [mhttpd,ERROR] [midas.c:10322:rpc_client_call,ERROR] call to "fedescant" on 
"grsmid00.triumf.ca" RPC "rc_transition": timeout waiting for reply
Wed Jul 10 06:24:02 2019 [mhttpd,ERROR] [midas.c:5495:cm_shutdown,ERROR] Client 'fedescant' not responding to 
shutdown command
Wed Jul 10 06:24:02 2019 [mhttpd,ERROR] [midas.c:5497:cm_shutdown,ERROR] Killing and Deleting client 'fedescant' 
pid 31482
Wed Jul 10 06:24:02 2019 [Logger,INFO] Client 'fedescant' on buffer 'SYSMSG' removed by cm_watchdog because 
process pid 31482 does not exist
Wed Jul 10 06:24:02 2019 [fegrifip09,INFO] Client 'fedescant' on buffer 'SYSTEM' removed by cm_watchdog because 
process pid 31482 does not exist
Wed Jul 10 06:24:03 2019 [mhttpd,INFO] Run #13456 stopped

And I think I tracked down where this comes from with help from Thomas Lindner. It is a problem in the communication via the A3818 card from CAEN. This seems to block the frontend, even though it still reacts normal to a shutdown. So no issue with midas, even if it seemed that way at first. Thanks for all your help!
  1680   08 Sep 2019 Vinzenz BildsteinBug Reporthttps redirect and ODB access
I'm not sure if these issues are related or not, but I'm getting an error
message when I want to access the root of the ODB via the webserver:
[mhttpd,ERROR] [mhttpd.cxx:563:rread,ERROR] Cannot read file '/root', read of
4096 returned -1, errno 21 (Is a directory)

I also tried turning the re-direct from http to https off, but this does not
seem to work. I also noticed that the redirect changes the localhost into a
hostname. Where does mongoose take this hostname from?

EDIT: Seems that the change of the hostname is due to a setting in /etc/hosts,
i.e. all my fault ...

EDIT: I think there was some issue with the mhttpd. When I checked the output (I
used screen to run it), it was full of these messages:

ss_semaphore_wait_for: semop/semtimedop(2588679) returned -1, errno 43
(Identifier removed)
al_check: Something is wrong with our semaphore, ss_semaphore_wait_for()
returned 408, aborting.
al_check: Cannot abort - this will lock you out of odb. From this point, MIDAS
will not work correctly. Please read the discussion at
https://midas.triumf.ca/elog/Midas/945

Restarted it and it stopped redirecting. So accessing the root of the ODB via
the webserver is the only issue now.
  1728   21 Oct 2019 Vinzenz BildsteinForumData for key truncated
I keep on getting messages like this:

16:25:35 [fecaen,ERROR] [odb.c:4567:db_get_data,ERROR] data for key
"/DAQ/params/VX1730/custom/Board 0/Channel 0/Input range" truncated

whenever I start my frontend. Input range is defined to be a BOOL and using
odbedit to read it shows:

Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Input range                     BOOL    1     4     75h  0   RWD  y

without any error message. The entry is read using

         size = sizeof(fInputRange);
         db_get_data(hDb, hSubKey, &fInputRange, &size, TID_BOOL);

where fInputRange is a bool.

Where does this message come from and how can I resolve this?
  859   11 Feb 2013 Wes GohnForumsend_tcp error
I am getting a series of errors from MIDAS that I do not understand, so I hope
someone can help me figure this out.

I am attempting to run many frontends on one machine. I can run 8 with no
problem, but if I try to add a 9th I get errors relating to send_tcp. 

I have tried adjusting the max event sizes and buffer sizes, but it has not
resolved the problem. I also tried adjusting the data rates and the total data
volume going through each frontend, but there was no change. And as far as I can
tell I am not up against any hardware limits.

The errors are repeated continuously while a run is going. The three errors I
get are:

16:45:22 [FakeData09,ERROR] [midas.c:9958:rpc_client_call,ERROR] send_tcp() failed
16:45:22 [FakeData09,ERROR] [frontend_rpc.c:191:rpc_call,ERROR] No RPC to master
16:45:22 [FakeData09,ERROR] [system.c:4166:send_tcp,ERROR]
send(socket=9,size=16) returned -1, errno: 32 (Broken pipe)

If you have any suggestions of how I can debug this, please let me know. Thanks!
  861   11 Feb 2013 Wes GohnForumsend_tcp error
> > I am getting a series of errors from MIDAS that I do not understand, so I hope
> > someone can help me figure this out.
> > 
> > I am attempting to run many frontends on one machine. I can run 8 with no
> > problem, but if I try to add a 9th I get errors relating to send_tcp. 
> > 
> > I have tried adjusting the max event sizes and buffer sizes, but it has not
> > resolved the problem. I also tried adjusting the data rates and the total data
> > volume going through each frontend, but there was no change. And as far as I can
> > tell I am not up against any hardware limits.
> > 
> > The errors are repeated continuously while a run is going. The three errors I
> > get are:
> > 
> > 16:45:22 [FakeData09,ERROR] [midas.c:9958:rpc_client_call,ERROR] send_tcp() failed
> > 16:45:22 [FakeData09,ERROR] [frontend_rpc.c:191:rpc_call,ERROR] No RPC to master
> > 16:45:22 [FakeData09,ERROR] [system.c:4166:send_tcp,ERROR]
> > send(socket=9,size=16) returned -1, errno: 32 (Broken pipe)
> > 
> > If you have any suggestions of how I can debug this, please let me know. Thanks!
> 
> Can you tell me
> 
> - why you need 9 frontends
> - what kind of data your frontends produce
> - how your event builder looks like and how you assemble the fragments
> - what messages/errors you see when you run odbedit BEFORE the crash
> 
> /Stefan

Our experiment will need 24 frontends that will each run on its own machine. For now we
want to run 24 "fake" frontends on one machine for testing purposes. 9 is the limit
where it stops working properly. 

We have a pulser that is giving us periodic data at a constant rate. We have a master
frontend running on a different PC in interrupt mode that assembles the events, and then
N "FakeData" frontends running in polled mode on a single PC. 

We do have an event builder, but we get these errors whether the event builder is
running or not.

At the start of a run, I see the following messages:

[mtransition,INFO] Run #21 started
Sat Feb 9 16:14:57 2013 [FakeData09,ERROR] [system.c:4166:send_tcp,ERROR]
send(socket=9,size=16) returned -1, errno: 104 (Connection reset by peer)
Sat Feb 9 16:14:57 2013 [FakeData09,ERROR] [midas.c:9958:rpc_client_call,ERROR]
send_tcp() failed
Sat Feb 9 16:14:57 2013 [FakeData09,ERROR] [frontend_rpc.c:191:rpc_call,ERROR] No RPC to
master
Sat Feb 9 16:14:57 2013 [master,ERROR] [midas.c:10844:recv_tcp_server,ERROR] Cannot
allocate 268435512 bytes for network buffer
Sat Feb 9 16:14:57 2013 [master,ERROR] [midas.c:12893:rpc_server_receive,ERROR]
recv_tcp_server() returned -1, abort
Sat Feb 9 16:14:57 2013 [master,TALK] Program 'FakeData09' on host 'fe01' aborted

After this it recycles just the first three errors that I mentioned above.
  865   19 Feb 2013 Wes GohnForumsend_tcp error

Thank you for the help. As it turns out, the problem was due to the fact that we were compiling MIDAS on our 64 bit backend machine, but one of the frontend machines is 32 bit. The problem was resolved by compiling a 32 bit version of MIDAS in
addition to the 64 bit version.
  990   15 Apr 2014 Wes GohnForumC++11 error
I am having some trouble creating a frontend that interacts with some libraries that use C++11. 

The flag I added to my MIDAS Makefile to get the C++11 part of the code to work is -std=c++0x. This 
causes an error in the equipment description in the frontend code.

The error I get is:

frontend.cpp:149: error: narrowing conversion of ‘-0x00000000000000001’ from ‘int’ to ‘WORD’ inside { 
}

This corresponds to the following in the MIDAS frontend code.

EQUIPMENT equipment[] = { 
  {
   "MWPC",                           /* equipment name */
   {1, TRIGGER_ALL,                  /* event ID, trigger mask */
     "BUF2",                        /* event buffer */
     EQ_POLLED | EQ_EB,              /* equipment type */
     LAM_SOURCE(0, 0xFFFFFF),        /* event source crate 0, all stations */
     "MIDAS",                        /* format */
     TRUE,                           /* enabled */
     RO_RUNNING,                     /* read only when running */
     1,                              /* poll for 1ms */
     0,                              /* stop run after this event limit */
     0,                              /* number of sub events */
     0,                              /* don't log history */
     "", "", "",},
    read_trigger_event,              /* readout routine */
  },

   {""}
};  <- this is line 149
#ifdef __cplusplus
}
#endif

Do you know a way to make this compatible with C++11?

Thanks!
  992   16 Apr 2014 Wes GohnForumC++11 error
> > I am having some trouble creating a frontend that interacts with some libraries that use C++11. 
> > 
> > The flag I added to my MIDAS Makefile to get the C++11 part of the code to work is -std=c++0x. This 
> > causes an error in the equipment description in the frontend code.
> > 
> > The error I get is:
> > 
> > frontend.cpp:149: error: narrowing conversion of ‘-0x00000000000000001’ from ‘int’ to ‘WORD’ inside { 
> > }
> > 
> > This corresponds to the following in the MIDAS frontend code.
> > 
> > EQUIPMENT equipment[] = { 
> >   {
> >    "MWPC",                           /* equipment name */
> >    {1, TRIGGER_ALL,                  /* event ID, trigger mask */
> >      "BUF2",                        /* event buffer */
> >      EQ_POLLED | EQ_EB,              /* equipment type */
> >      LAM_SOURCE(0, 0xFFFFFF),        /* event source crate 0, all stations */
> >      "MIDAS",                        /* format */
> >      TRUE,                           /* enabled */
> >      RO_RUNNING,                     /* read only when running */
> >      1,                              /* poll for 1ms */
> >      0,                              /* stop run after this event limit */
> >      0,                              /* number of sub events */
> >      0,                              /* don't log history */
> >      "", "", "",},
> >     read_trigger_event,              /* readout routine */
> >   },
> > 
> >    {""}
> > };  <- this is line 149
> > #ifdef __cplusplus
> > }
> > #endif
> > 
> > Do you know a way to make this compatible with C++11?
> > 
> > Thanks!
> 
> Is this maybe related to the LAM_SOURCE(0, 0xFFFFFFFF) where 0xFFFFFFFF is -1. I guess you are not using CAMAC, so just replace the 
> LAM_SOURCE(...) with zero and try again.
> 
> /Stefan

Thanks for the suggestion. It looks like it is instead the TRIGGER_ALL that is causing the problem. TRIGGER_ALL is defined as -1 in midas.h. If I replace TRIGGER_ALL with 0 in the 
frontend, it compiles, but if I use -1, I get the same error. I do not think that I want my trigger mask set to 0. Do you have a suggestion of how to get around this?

To answer the other questions, we are running on SLF6. I am building a frontend for a MWPC to read data from CAEN TDCs.
  1048   17 Mar 2015 Wes GohnForumPosgresQL
For our MIDAS installation at Fermilab, it is necessary that we be able to write to a PosgresQL 
database (MySQL is not supported here). This will be required of both mlogger and mscb. 

Has anyone done this before? And do you know of a relatively simple way of implementing it, or do 
we need to replicate the mysql functions that are already in the mlogger/mscb code to add functions 
that perform the equivalent Posgres commands?

Thanks!
Wes
  1083   29 Jul 2015 Wes GohnForumerror
SIGSEGV is a segmentation fault. Most often it means some ODB parameter is out of bounds or there is 
an invalid memcpy somewhere in your code.

> Hello, I am new in the forum. We are running an experiment for a week with no
> problems. Now we add a detector a we found an error. Even we come back to our
> previous configuration the error continues appearing. Please, may someone help
> us? You can find the error in the attachment. Thanks!
  1088   10 Aug 2015 Wes GohnForumbk_create change
After pulling the newest version of midas, our compilation would fail on
bk_create, with the error:

frontend.cpp:954: error: invalid conversion from ‘DWORD**’ to ‘void**’
frontend.cpp:954: error:   initializing argument 4 of ‘void bk_create(void*,
const char*, WORD, void**)’

I noticed a change to the function in midas.c that changes the type of pdata
from a pointer to a double pointer, and changes 

      *((void **) pdata) = pbk + 1;
to
      *pdata = pbk + 1;

The fix is simple. In each call to bk_create, I changed it to:

bk_create(pevent, bk_name, TID_DWORD, (void**)&pdata); 

I suggest updating the documentation. Also, why the change? Does it add some
improvement in efficiency?
ELOG V3.1.4-2e1708b5