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Commit e8744fd4 authored by Jamie Gennis's avatar Jamie Gennis
Browse files

atrace: make clock & bus bw tracing optional 

This change makes enabling clock tracing and bus bandwidth tracing depend on
whether the device's kernel supports these features.  If it's not supported it
will be skipped.

Change-Id: I51d57299693635b0ecebb75de5dccd5b62d47be3
parent 99be77cf

cmds/atrace/atrace.c

+23 −18
Original line number Diff line number Diff line
@@ -93,6 +93,11 @@ static const char* k_tracePath = 
static const char* k_traceMarkerPath =

    "/sys/kernel/debug/tracing/trace_marker";



// Check whether a file exists.

static bool fileExists(const char* filename) {

    return access(filename, F_OK) != -1;

}



// Write a string to a file, returning true if the write was successful.

bool writeStr(const char* filename, const char* str)

{
@@ -151,11 +156,14 @@ static bool setSchedSwitchTracingEnable(bool enable) 
// Enable or disable tracing of the Bus utilization.

static bool setBusUtilizationTracingEnable(bool enable)

{

    bool ok = false;

    bool ok = true, oneSet = false;

    // these can be platform specific so make sure that at least

    // one succeeds.

    ok |= setKernelOptionEnable(k_memoryBusEnablePath, enable);

    return ok;

    if (fileExists(k_memoryBusEnablePath)) {

        ok &= setKernelOptionEnable(k_memoryBusEnablePath, enable);

        oneSet |= ok;

    }

    return ok && (oneSet || !enable);

}



// Enable or disable tracing of the CPU clock frequency.
@@ -163,7 +171,9 @@ static bool setFrequencyTracingEnable(bool enable) 
{

    bool ok = true;

    ok &= setKernelOptionEnable(k_cpuFreqEnablePath, enable);

    if (fileExists(k_clockSetRateEnablePath)) {

        ok &= setKernelOptionEnable(k_clockSetRateEnablePath, enable);

    }

    return ok;

}
@@ -177,7 +187,11 @@ static bool setCpuIdleTracingEnable(bool enable) 
// the CPU load.

static bool setGovernorLoadTracingEnable(bool enable)

{

    return setKernelOptionEnable(k_governorLoadEnablePath, enable);

    bool ok = true;

    if (fileExists(k_governorLoadEnablePath) || enable) {

        ok &= setKernelOptionEnable(k_governorLoadEnablePath, enable);

    }

    return ok;

}



// Enable or disable tracing of the kernel workqueues.
@@ -232,11 +246,6 @@ static bool setGlobalClockEnable(bool enable) 
    return writeStr(k_traceClockPath, enable ? "global" : "local");

}



// Check whether a file exists.

static bool fileExists(const char* filename) {

    return access(filename, F_OK) != -1;

}



// Enable tracing in the kernel.

static bool startTrace(bool isRoot)

{
@@ -245,12 +254,9 @@ static bool startTrace(bool isRoot) 
    // Set up the tracing options that don't require root.

    ok &= setTraceOverwriteEnable(g_traceOverwrite);

    ok &= setSchedSwitchTracingEnable(g_traceSchedSwitch);

    ok &= setBusUtilizationTracingEnable(g_traceBusUtilization);

    ok &= setFrequencyTracingEnable(g_traceFrequency);

    ok &= setCpuIdleTracingEnable(g_traceCpuIdle);

    if (fileExists(k_governorLoadEnablePath) || g_traceGovernorLoad) {

    ok &= setGovernorLoadTracingEnable(g_traceGovernorLoad);

    }

    ok &= setTraceBufferSizeKB(g_traceBufferSizeKB);

    ok &= setGlobalClockEnable(true);
@@ -258,6 +264,7 @@ static bool startTrace(bool isRoot) 
    // require root should have errored out earlier if we're not running as

    // root.

    if (isRoot) {

        ok &= setBusUtilizationTracingEnable(g_traceBusUtilization);

        ok &= setWorkqueueTracingEnabled(g_traceWorkqueue);

        ok &= setDiskTracingEnabled(g_traceDisk);

    }
@@ -281,14 +288,12 @@ static void stopTrace(bool isRoot) 
    // Set the options back to their defaults.

    setTraceOverwriteEnable(true);

    setSchedSwitchTracingEnable(false);

    setBusUtilizationTracingEnable(false);

    setFrequencyTracingEnable(false);

    if (fileExists(k_governorLoadEnablePath)) {

    setGovernorLoadTracingEnable(false);

    }

    setGlobalClockEnable(false);



    if (isRoot) {

        setBusUtilizationTracingEnable(false);

        setWorkqueueTracingEnabled(false);

        setDiskTracingEnabled(false);

    }