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ASYN Trace Masks (Debugging IOC, ASYN)
For asyn based drivers, such as stream device, additional information printing can be enabled on a port via commands from the ioc shell. The commands let you see what bytes are being sent and received, and also the flow of control/logic.
The two commands you need are:
asynSetTraceIOMask("L0", -1, 0x2)
asynSetTraceMask("L0", -1, 0x9)
Note: if the device's messages are longer than 80 characters, you should increase the buffer size by also running:
asynSetTraceIOTruncateSize("L0", -1, 1024)
Where 1024 is the maximum message length you expect - could be increased if your device requires it.
to turn off use
asynSetTraceMask("L0", -1, 0x1)
This determines what you see and is set to 0x1 (ASYN_TRACE_ERROR) by default. The following additional values can be ORed together and optionally set:
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0x1: ASYN_TRACE_ERROR - Print error messages (default) -
0x2: ASYN_TRACEIO_DEVICE - Device support reports I/O activity. -
0x4: ASYN_TRACEIO_FILTER - Any layer between device support and the low level driver e.g. asyn interpose functions -
0x8: ASYN_TRACEIO_DRIVER - Low level driver reports I/O activity -
0x10: ASYN_TRACE_FLOW - Report logic flow -
0x20: ASYN_TRACE_WARNING - Report warnings, i.e. conditions between ASYN_TRACE_ERROR and ASYN_TRACE_FLOW
If L0 if your asyn port, then
asynSetTraceMask("L0",-1,0x9)
will enable ASYN_TRACE_ERROR and ASYN_TRACEIO_DRIVER for all addresses (-1) on port "L0" which is a good place to start for debugging. You may also want to use ASYN_TRACE_FLOW but this can print a bit too much depending on the driver and you may loose your IO device messages amongst them. If you want to try this separately then e.g.
asynSetTraceMask("L0",0,0x11)
will enable ASYN_TRACE_ERROR and ASYN_TRACE_FLOW on port "L0" but just for address 0.
To see output of interpose functions such as asynInterposeThrottle add 0x4, so 0x9 become 0xD for example
If ASYN_TRACEIO_DRIVER has been enabled, then this mask determines the format of the output produced when reporting I/O. The default is ASYN_TRACEIO_NODATA so the count of bytes transferred is reported, but the bytes themselves are not printed.
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0x0(ASYN_TRACEIO_NODATA) - Print count of bytes transferred, but not bytes themselves -
0x1(ASYN_TRACEIO_ASCII) - Print bytes with a "%s" style format -
0x2(ASYN_TRACEIO_ESCAPE) - Calls epicsStrPrintEscaped() to display bytes -
0x4(ASYN_TRACEIO_HEX) - Print hexadecimal values of each byte with " %2.2x"
So
asynSetTraceIOMask("L0",-1,0x2)
would enable ASYN_TRACEIO_ESCAPE style printing of all bytes read/written by the asyn driver via port "L0", which is a good place to start
This mask determines the information printed at the start of each message above. The default is ASYN_TRACEINFO_TIME which just adds a timestamp, normally this is sufficient but it can be changed by calling asynSetTraceInfoMask with a combination of flags:
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0x1(ASYN_TRACEINFO_TIME) prints the date and time of the message (default) -
0x2(ASYN_TRACEINFO_PORT) prints [port,addr,reason], where port is the port name, addr is the asyn address, and reason is pasynUser->reason. These are the 3 pieces of "addressing" information in asyn. -
0x4(ASYN_TRACEINFO_SOURCE) prints the file name and line number, i.e. [FILE,LINE] where the asynPrint or asynPrintIO statement occurs. -
0x8(ASYN_TRACEINFO_THREAD) prints the thread name, thread ID and thread priority, i.e. [epicsThreadGetNameSelf(), epicsThreadGetIdSelf(), epicsThreadGetPrioritySelf()].
e.g. to print time and port details at start of each message
asynSetTraceInfoMask("L0",-1,0x3)
By default the trace output is sent to the epics error log (which by default echoes to console too), but it can instead be sent to file e.g.
asynSetTraceFile("L0",-1,"temp.log")
In your st.cmd, or at the EPICS prompt from a console session, use:
var streamDebug 1
This will turn on debug logging from stream device which is very verbose.
In your st.cmd, or at the EPICS prompt from a console session, use:
var caPutLogToConsole 1
This will log all details of caput etc to the ioc to console using the caPutLog mechanism.