Experimental Physics and
Industrial Control System

Hi all,

attached is a test program that can reproduce the problem. Since it uses sysClkRateGet(), it compiles only on vxWorks.

It calls pasynOctet->readRaw() once with pasynUser->timeout=1.1/sysClkRateGet() and once with pasynUser->timeout=1.0/sysClkRateGet().

In the first case, readRaw() returns asynTimeout, as expected. In the second case, readRaw() does not return.

I print the thread ID before calling readRaw(). When I do 'tt' on the thread ID, readRaw() suddenly returns asynTimeout. Very strange.

A Makefile is also attached. No records are required. Just set up a TCP  server somewhere, call drvAsynIPPortConfigure  and run:

readTimeoutTest "portname".

BTW: As long as readRaw() hangs, I could not open a channel access connection to records on that IOC and the dbior command hangs when trying to report drvAsyn.

I use asynDriver version 4-5, EPICS base R3.14.8, vxWorks 5.5 on MVME2300 (ppc604).

Dirk

Dirk Zimoch wrote:

Hi Marty, Jeff et al

When asynOctet->read() (or at least readRaw() of the TCP port driver) is called on vxWorks with pasynUser->timeout < 1/sysClkRateGet() [normally about 16 ms], the read call hangs and does never time out.

I think it is actually a problem with epicsTimer, which never expires for timeouts < 1/sysClkRateGet(). But I have not tested this.

I think, a timer should wait at least the specified amount of time, thus always round up to at least one tick.

Dirk

-- 

Dr. Dirk Zimoch

Swiss Light Source

Paul Scherrer Institut

Computing and Controls

phone +41 56 310 5182

fax   +41 56 310 4413

#include <asynDriver.h>

#include <asynOctet.h>

#include <epicsThread.h>

#include <sysLib.h>

static char* asynStatusStr[] = {"Success", "Timeout", "Overflow", "Error"};

void readTimeoutTestHandleRequest(asynUser* pasynUser)

{

    asynInterface* pasynInterface;

    asynOctet* pasynOctet;

    void* pvtOctet;

    char buffer[1];

    asynStatus status;

    size_t received;

    int eomReason;

    

    printf ("readTimeoutTestHandleRequest, thread = %s %p\n",

        epicsThreadGetNameSelf(), epicsThreadGetIdSelf());

        

    pasynInterface = pasynUser->userPvt;

    pasynOctet =  pasynInterface->pinterface;

    pvtOctet = pasynInterface->drvPvt;

    

    pasynUser->timeout = 1.1 / sysClkRateGet();

    printf ("calling pasynOctet->readRaw() with %g seconds timeout\n",

        pasynUser->timeout);

    status = pasynOctet->readRaw(pvtOctet, pasynUser, buffer, 1,

        &received, &eomReason);

    printf ("pasynOctet->readRaw() returned status %s\n",

        asynStatusStr[status]);

    pasynUser->timeout = 1.0 / sysClkRateGet();

    printf ("calling pasynOctet->readRaw() with %g seconds timeout\n",

        pasynUser->timeout);

    status = pasynOctet->readRaw(pvtOctet, pasynUser, buffer, 1,

        &received, &eomReason);

    printf ("pasynOctet->readRaw() returned status %s\n",

        asynStatusStr[status]);

}

void readTimeoutTestTimeout(asynUser* pasynUser)

{

    printf ("pasynManager->queueRequest() timed out\n");

}

int readTimeoutTest(char * port, int addr)

{

    asynStatus status;

    asynUser* pasynUser;

    asynInterface* pasynInterface;

    

    pasynUser = pasynManager->createAsynUser(readTimeoutTestHandleRequest,

        readTimeoutTestTimeout);

    if (pasynManager->connectDevice(pasynUser, port, addr) !=

        asynSuccess)

    {

        printf ("No such device: %s,%d\n", port, addr);

        return ERROR;

    }

    pasynInterface = pasynManager->findInterface(pasynUser,

        asynOctetType, TRUE);

    if (!pasynInterface)

    {

        printf ("No asynOctet interface: %s,%d\n", port, addr);

        return ERROR;

    }

    pasynUser->userPvt = pasynInterface;

    status = pasynManager->queueRequest(pasynUser,

        asynQueuePriorityHigh, 10.0);

    if (status != asynSuccess)

    {

        printf ("pasynManager->queueRequest() failed: %s\n",

            pasynUser->errorMessage);

        return ERROR;

    }

    return OK;

}

TOP=../..

include $(TOP)/configure/CONFIG

HOST_OPT = NO

PROD_vxWorks = asynApp

DBD  = asynApp.dbd

asynApp_DBD += base.dbd

PROD_SRCS += asynApp_registerRecordDeviceDriver.cpp

PROD_SRCS += readTimeoutTest.c

asynApp_DBD += drvAsynIPPort.dbd

PROD_LIBS += asyn

PROD_LIBS += $(EPICS_BASE_IOC_LIBS)

include $(TOP)/configure/RULES

-- 

Eric Norum <[email protected]>

Advanced Photon Source                     

Argonne National Laboratory

(630) 252-4793