Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Tue, 11 Apr 2017 16:24:53 +0000

Hi Pawel,

What is the SCAN field of your waveform record?  I suspect it is probably periodic ("1 second", etc.).  For this application you should set it to SCAN="I/O Intr".  Then the waveform record will process each time your driver does a callback to device support.  If the record is periodically processing at 1 second and your driver is doing callbacks faster than 1 Hz then you will see the error you report.

Mark

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Pawel Plewinski
Sent: Tuesday, April 11, 2017 8:49 AM
To: [email protected]
Subject: [AsynPortDriver] "Multiple interrupt callbacks between processing" warning with multiple arrays

Hi,

I've recently written asyn-based device support for a custom device 
communicating over PCIe. One of its functions is to periodically 
retrieve 4 waveforms from 4 channels, which is done in a separate 
thread, from which the callback function is called to notify asyn about 
change. I heavily based the code on the AsynPortDriver example.
The driver works, however if the update rate is lower than 1 second, 
strange warning appears in the console at the time of every refresh (and 
that's only for one of 4 channels), namely:

2017/04/11 15:42:08.682 PIEZO:OSC-CH0-WAVEFORM 
devAsynFloat64Array::interruptCallbackInput
\000\000\000\000\000@\205?\000\000\000\000\000\300\202?\000\000\000\000\000\000\204?\000\000\000\000\000\000\204?\000\000\000\000\000\300\202?\000\000\000\000\000\000\204?\000\000\000\000\000@\205?\000\000\000\000\000\000\204?\000\000\000\000\000\300\202?\000\000\000\000\000\000\204?
2017/04/11 15:42:08.682 PIEZO:OSC-CH0-WAVEFORM 
devAsynFloat64Array::processCommon, warning, multiple interrupt 
callbacks between processing

The parameters passed to the top level constructor are
    : asynPortDriver(portName,
                     4, /* maxAddr */
                     (int)NUM_SCOPE_PARAMS,
                     asynInt32Mask | asynFloat64Mask | 
asynFloat64ArrayMask | asynEnumMask | asynDrvUserMask, /* Interface mask 
*/
                     asynInt32Mask | asynFloat64Mask | 
asynFloat64ArrayMask | asynEnumMask,  /* Interrupt mask */
                     ASYN_MULTIDEVICE, /* asynFlags.  This driver does 
not block and it is not multi-device, so flag is 0 */
                     1, /* Autoconnect */
                     0, /* Default priority */
                     0) /* Default stack size*/

The readback thread code:

void piezoPortDriver::readbackTask(void)
{
    while (1) {
            bool stopped = false;

            lock();
            auto new_data = osc->fetch_data(vtim, vdat);
            unlock();

            if (!stopped)
            {
                lock();
                this->osc_update_trigger();
                unlock();
            }
         callParamCallbacks();

         for (int i = 0; i < 4; i++){
           doCallbacksFloat64Array(vdat[i].data(), vdat[i].size(), 
P_OscWaveform, i);
         }
         usleep(100000);
     }
}

The fetch_data method reads four 1000-element double vectors from PCIe.

Could you give me some suggestions what may be wrong?

Regards,
Paweł Plewiński
Department of Microelectronics and Computer Science
Lodz University of Technology

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System