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  785   01 Mar 2012 Stefan RittBug ReportProblem with semaphores
> Anyhow, if anybody can suggest such an advanced locking library it would be great. Will save me the 
> effort of writing one.

Hi Konstantin,

yes there is a good way, which I used during development of the buffer manager function. Put in each sm_xxx function a cm_msg(M_DEBUG, ...) to 
generate a debug system message. They go only into the SYSMSG ring buffer and thus are light weight and don't influence the timing much. You can 
keep odbedit open to see these messages, but there is also another way. You can write a little program which dumps the whole SYSMSG buffer, which 
you can call when the lock happens. You then look "backwards" in time and get all messages stored there, depending of the size of the SYSMSG buffer of 
course. Of course this only works if the lock does not happen on the SYSMSB buffer itself. In that case you have to produce M_LOG messages which are 
written to the logging file. This will influence the timing slightly (the file might grow rapidly) but you are independent of semaphores.

The interesting thing is that in the MEG experiment (9 Front-ends, Event Builder, Logger, Lazylogger, ....) we run for months without any lock up. So I 
might suspect it's caused in your case from a program only you are using.

Best regards,
Stefan
  786   18 Apr 2012 Exaos LeeBug ReportBuild error with mlogger: invalid conversion from ‘void*’ to ‘gzFile’
I tried to build MIDAS under ArchLinux, failed on errors as following:
src/mlogger.cxx: In function ‘INT midas_flush_buffer(LOG_CHN*)’:
src/mlogger.cxx:1011:54: error: invalid conversion from ‘void*’ to ‘gzFile’ [-fpermissive]
In file included from src/mlogger.cxx:33:0:
/usr/include/zlib.h:1318:21: error:   initializing argument 1 of ‘int gzwrite(gzFile, voidpc, unsigned int)’ [-fpermissive]
src/mlogger.cxx: In function ‘INT midas_log_open(LOG_CHN*, INT)’:
src/mlogger.cxx:1200:79: error: invalid conversion from ‘void*’ to ‘gzFile’ [-fpermissive]
In file included from src/mlogger.cxx:33:0:
Please refer to attachment elog:786/1 for detail. There are also many warnings listed.

This error can be supressed by adding -fpermissive to CXXFLAGS. But the error message is correct."gzFile" is not equal to "void *"! C allows implicit casts between void* and any pointer type, C++ doesn't allow that. It's better to fix this error. A quick fix would be adding explicit casts. But I'm not sure what is the proper way to fix this.
Attachment 1: mlogger-err.log.gz
  787   19 Apr 2012 Stefan RittBug ReportBuild error with mlogger: invalid conversion from ‘void*’ to ‘gzFile’

Exaos Lee wrote:
I tried to build MIDAS under ArchLinux, failed on errors as following:
src/mlogger.cxx: In function ‘INT midas_flush_buffer(LOG_CHN*)’:
src/mlogger.cxx:1011:54: error: invalid conversion from ‘void*’ to ‘gzFile’ [-fpermissive]
In file included from src/mlogger.cxx:33:0:
/usr/include/zlib.h:1318:21: error:   initializing argument 1 of ‘int gzwrite(gzFile, voidpc, unsigned int)’ [-fpermissive]
src/mlogger.cxx: In function ‘INT midas_log_open(LOG_CHN*, INT)’:
src/mlogger.cxx:1200:79: error: invalid conversion from ‘void*’ to ‘gzFile’ [-fpermissive]
In file included from src/mlogger.cxx:33:0:
Please refer to attachment elog:786/1 for detail. There are also many warnings listed.

This error can be supressed by adding -fpermissive to CXXFLAGS. But the error message is correct."gzFile" is not equal to "void *"! C allows implicit casts between void* and any pointer type, C++ doesn't allow that. It's better to fix this error. A quick fix would be adding explicit casts. But I'm not sure what is the proper way to fix this.


Ah, dumb gcc gets pickier and pickier. I added a case (gzFile)log_chn->gzfile which fixes the error. I cannot put gzFile already into the header file since the zlib header is included after the midas header, otherwise we get some other problems. The SVN version with the fix is 5275.
  788   25 Apr 2012 Konstantin OlchanskiBug ReportBuild error with mlogger: invalid conversion from ‘void*’ to ‘gzFile’
Stefan's fix is incomplete - the "gzFile" cast is needed for all calls to zlib, not just those that some version 
of GCC happens to complain about. Fixed.
svn rev 5286.

BTW, I read the midas elog via email and if you post html or elcode messages, I receive complete 
gibberish. For prompt service, please select message type "plain". (yes, you cannot use fancy colours and 
blinking text, but better than me not reading your stuff at all).

BTW2, for easier reading, please include error messages as plain text in your message. As opposed to 
compressed attachements.

K.O.
  789   27 Apr 2012 Stefan RittBug ReportBuild error with mlogger: invalid conversion from ‘void*’ to ‘gzFile’

KO wrote:
BTW, I read the midas elog via email and if you post html or elcode messages, I receive complete
gibberish. For prompt service, please select message type "plain". (yes, you cannot use fancy colours and
blinking text, but better than me not reading your stuff at all).

BTW2, for easier reading, please include error messages as plain text in your message. As opposed to
compressed attachements.

K.O.


BTW3, if you use a real email program you don't get glibberish. I know some people prefer good-old-text-only pine, but I'm sure you do not use the ascii-only browser lynx to browse the internet, right? So if you browse the web in graphics, why not read your email in graphics as well. Better change yourself than the whole rest of the world Wink
  790   09 Jun 2012 Greg ChristianBug Report_net_send_buffer realloc
In midas.c, I noticed that memory is only allocated to the global buffer 
_net_send_buffer by calling realloc() from within the function 
resize_net_send_buffer() (at least this was the only place I could find 
allocation to _net_send_buffer happening). This can cause problems for a couple 
of reasons:

1) _net_send_buffer is not set to NULL when declared. To my understanding, this 
makes the first call to realloc(_net_send_buffer, /*size*/) undefined. When 
passed a pointer that has not previously been allocated, realloc() acts like 
malloc() only if the pointer equal to NULL. Otherwise, the behavior is undefined 
and usually causes a crash.

2) cm_disconect_experiment() calls free(_net_send_buffer) but does not set its 
value to NULL. Thus if a client tries to include more than one 
connect...disconnect cycle within an application, there is undefined behavior 
the next time realloc(_net_send_buffer, ...) gets called.

I think that any potential allocation issues involving _net_send_buffer could be 
solved by:

1) Initializing _net_send_buffer to NULL.

2) In cm_disconnect_experiment(), changing
>   M_FREE(_net_send_buffer); 
to 
>   M_FREE(_net_send_buffer);
>   _net_send_buffer = NULL;
  791   10 Jun 2012 Konstantin OlchanskiBug Report_net_send_buffer realloc
> In midas.c, ...
>
> 1) _net_send_buffer is not set to NULL when declared.

_net_send_buffer is a global variable. All global variables are automatically initialized to zero before the program 
starts.

static char*x; // = NULL; is redundant
char*y=realloc(x, 100);  // x is NULL, usage is correct

> 2) cm_disconect_experiment() calls free(_net_send_buffer) but does not set its 
> value to NULL.

My copy of midas.c (svn rev 5256) sets _net_send_buffer to NULL:

   if (_net_send_buffer_size > 0) { 
      M_FREE(_net_send_buffer); 
      _net_send_buffer_size = 0; 
   } 
 
What version of midas do you have? (svn info .)

K.O.
  792   10 Jun 2012 Greg ChristianBug Report_net_send_buffer realloc
> > In midas.c, ...
> >
> > 1) _net_send_buffer is not set to NULL when declared.
> 
> _net_send_buffer is a global variable. All global variables are automatically 
initialized to zero before the program 
> starts.
> 
> static char*x; // = NULL; is redundant
> char*y=realloc(x, 100);  // x is NULL, usage is correct
>

Ah,okay. I was not aware of this feature of global variables.

 
> > 2) cm_disconect_experiment() calls free(_net_send_buffer) but does not set 
its 
> > value to NULL.
> 
> My copy of midas.c (svn rev 5256) sets _net_send_buffer to NULL:
> 
>    if (_net_send_buffer_size > 0) { 
>       M_FREE(_net_send_buffer); 
>       _net_send_buffer_size = 0; 
>    } 
>  
> What version of midas do you have? (svn info .)
> 
> K.O.

I have version 5256 also (matches what you posted), but I only see 
_net_send_buffer_size being set to 0, not _net_send_buffer itself. In midas.h, 
M_FREE(x) only expands to free(x) if _MEM_DBG is not defined.
  793   11 Jun 2012 Konstantin OlchanskiBug Report_net_send_buffer realloc
> > > In midas.c, ...
> > >
> > > 1) _net_send_buffer is not set to NULL when declared.
> 
> Ah,okay. I was not aware of this feature of global variables.
> 

RTFM K&R "The C programming language". 
http://en.wikipedia.org/wiki/The_C_Programming_Language

>  
> > > 2) cm_disconect_experiment() calls free(_net_send_buffer) but does not set 
> its value to NULL.
>

Confirmed. Sorry for confusion in my previous message. Set the pointer to NULL after free() is good practice.

But note that calling cm_connect and cm_disconnect multiple times is unusual use of MIDAS and you will most 
likely find more breakage.

K.O.
  794   13 Jun 2012 Exaos LeeBug ReportCannot start/stop run through mhttpd
Revision: r5286 
Platform: Debian Linux 6.0.5 AMD64, with packages from squeeze-backports 
Problem:
After building and installation, using the script 'start_daq.sh' to start
'sampleexpt'. Everything seems fine. But I cannot start a run through web. Using
'odbedit' and 'mtransition' to start/stop a run works fine. So, what may cause
such a problem?
  795   13 Jun 2012 Konstantin OlchanskiBug ReportCannot start/stop run through mhttpd
> Revision: r5286 
> Platform: Debian Linux 6.0.5 AMD64, with packages from squeeze-backports 
> Problem:
> After building and installation, using the script 'start_daq.sh' to start
> 'sampleexpt'. Everything seems fine. But I cannot start a run through web. Using
> 'odbedit' and 'mtransition' to start/stop a run works fine. So, what may cause
> such a problem?

Well, it's mhttpd who cannot start the run, not you. So what happens when you press
the "start run" button? Any errors in midas.log or in midas messages? Is mtransition
in your PATH?

K.O.
  796   13 Jun 2012 Konstantin OlchanskiForumladd00.triumf.ca https ssl certificate update
The HTTPS SSL certificate on ladd00.triumf.ca has been updated. Same as the old
certificate, the new one is self-signed and your web browser may complain about
that and ask you to "save a security exception".

When you save the new certificate, you can verify that you are connected to the
real ladd00.triumf.ca by comparing the "SHA1 fingerprint" reported by your web
browser to the one given below (as reported by "svn update"):

Certificate information:
 - Hostname: ladd00.triumf.ca
 - Valid: from Wed, 13 Jun 2012 22:31:51 GMT until Thu, 13 Jun 2013 22:31:51 GMT
 - Issuer: DAQ, TRIUMF, Vancouver, BC, CA
 - Fingerprint: 82:95:78:cb:78:d3:93:1d:d4:c8:e8:1a:64:0f:62:04:2d:0e:c3:4a

K.O.
  797   13 Jun 2012 Exaos LeeBug ReportCannot start/stop run through mhttpd
> Well, it's mhttpd who cannot start the run, not you. So what happens when you press
> the "start run" button? Any errors in midas.log or in midas messages? Is mtransition
> in your PATH?
After pressing "start run", there is a message displayed: "Run start requested". There
is no error in midas.log. And mtransition is actually in my PATH. I even looked into
"mhttpd.cxx" and found where "cm_transition" is called for starting a run. I have no
clue to grasp the reason.
  798   14 Jun 2012 Exaos LeeBug ReportCannot start/stop run through mhttpd
> > Revision: r5286 
> > Platform: Debian Linux 6.0.5 AMD64, with packages from squeeze-backports 
> > Problem:
> > After building and installation, using the script 'start_daq.sh' to start
> > 'sampleexpt'. Everything seems fine. But I cannot start a run through web. Using
> > 'odbedit' and 'mtransition' to start/stop a run works fine. So, what may cause
> > such a problem?
> 
> Well, it's mhttpd who cannot start the run, not you. So what happens when you press
> the "start run" button? Any errors in midas.log or in midas messages? Is mtransition
> in your PATH?
> 
> K.O.

I found the problem only appears when I run mhttpd in scripts, whether bash or python.
And I'm quite sure that the MIDAS environments (e.g. PATH, MIDAS_EXPTAB, MIDASSYS, etc.)
are set in such scripts. If I start mhttpd in an xterm with or without "-D", it works
fine. So, what's the difference between invoking mhttpd directly and through a script?
  799   14 Jun 2012 Stefan RittBug ReportCannot start/stop run through mhttpd
> I found the problem only appears when I run mhttpd in scripts, whether bash or python.
> And I'm quite sure that the MIDAS environments (e.g. PATH, MIDAS_EXPTAB, MIDASSYS, etc.)
> are set in such scripts. If I start mhttpd in an xterm with or without "-D", it works
> fine. So, what's the difference between invoking mhttpd directly and through a script?

When you start it with "-D", then mhttpd become a daemon. According to linux rules, it has to "cd /", so it lives in the 
root directory, in order not to block any NFS mount/unmount. If something with the path is not correct then, mhttpd 
cannot find mtransition then. Once I fixed that problem my moving mtransition to /usr/bin.

Stefan
  800   14 Jun 2012 Konstantin OlchanskiBug ReportCannot start/stop run through mhttpd
> > I found the problem only appears when I run mhttpd in scripts, whether bash or python.
> > And I'm quite sure that the MIDAS environments (e.g. PATH, MIDAS_EXPTAB, MIDASSYS, etc.)
> > are set in such scripts. If I start mhttpd in an xterm with or without "-D", it works
> > fine. So, what's the difference between invoking mhttpd directly and through a script?
> 
> When you start it with "-D", then mhttpd become a daemon. According to linux rules, it has to "cd /", so it lives in the 
> root directory, in order not to block any NFS mount/unmount. If something with the path is not correct then, mhttpd 
> cannot find mtransition then. Once I fixed that problem my moving mtransition to /usr/bin.
> 

I agree. Somehow mhttpd cannot run mtransition. I am not super happy with this dependance on user $PATH settings and the inability to capture error messages 
from attempts to start mtransition. I am now thinking in the direction of running mtransition code by forking. But remember that mlogger and the event builder also
have to use mtransition to stop runs (otherwise they can dead-lock). So an mhttpd-only solution is not good enough...

K.O.
  801   14 Jun 2012 Konstantin OlchanskiBug ReportCannot start/stop run through mhttpd
> > > Revision: r5286 
> > > Platform: Debian Linux 6.0.5 AMD64, with packages from squeeze-backports 
> 
> I found the problem only appears when I run mhttpd in scripts, whether bash or python.
> And I'm quite sure that the MIDAS environments (e.g. PATH, MIDAS_EXPTAB, MIDASSYS, etc.)
> are set in such scripts. If I start mhttpd in an xterm with or without "-D", it works
> fine.

Right. I see Debian 6.0.5 just came out hot off the presses. Would be good to fix this problem.

As a work around, can you run mhttpd without "-D", but in the background, i.e. "mhttpd -p xxx >& mhttpd.log &"?

Also what are your $PATH settings?

> So, what's the difference between invoking mhttpd directly and through a script?

As Stefan mentioned, "-D" invokes some nasty unix magic to disconnect the process from the user login session. It is 
possible that this magic breaks in the latest Debian.

MIDAS "-D" does roughly the same thing as "nohup".

K.O.
  802   15 Jun 2012 Konstantin OlchanskiBug Reportbk_delete uses memcpy instead of memmove
> In midas.c, the bk_delete function removes a bank by decrementing the total
> event size and then copying the remaining banks into the location of the first
> using memcpy from string.h.

Replaced some memcpy() with memmove(), including bk_delete().

svn rev 5293
K.O.
  803   15 Jun 2012 Konstantin OlchanskiBug Report_net_send_buffer realloc
> 2) cm_disconect_experiment() calls free(_net_send_buffer) but does not set its 
> value to NULL.

Set pointer to NULL after free() in these files:

M       odb.c
M       sequencer.cxx
M       mlogger.cxx
M       mhttpd.cxx
M       midas.c

svn rev 5294
K.O.
  804   20 Jun 2012 Konstantin OlchanskiInfolazylogger write to HADOOP HDFS
I tried using the lazylogger "Disk" method to write into a HADOOP HDFS clustered filesystem and found a 
number of problems. I ended up replacing the lazylogger lazy_copy() function that still uses former YBOS 
code with a new lazy_disk_copy() function that uses generic fread/fwrite. Also fixed the situation where 
lazylogger cannot cleanly stop from the mhttpd "programs/stop" button while it is busy writing (the fix 
works only for the "Disk" method).

(Note that one can also use the "Script" method for writing into HDFS)

Anyhow, the new lazylogger writes into HDFS just fine and I expect that it would also work for writing into 
DCACHE using PNFS (if ever we get the SL6 PNFS working with our DCACHE servers).

Writing into our test HDFS cluster runs at about 20 MiBytes/sec for 1GB files with replication set to 3.

svn rev 5295
K.O.
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