Class PeriodicCondition

Holoscan v2.1.0

Base Type

class PeriodicCondition : public holoscan::gxf::GXFCondition

Condition class to support periodic execution of operators.

The recess (pause) period indicates the minimum amount of time that must elapse before the compute() method can be executed again. The period is specified as a string containing a number and an (optional) unit. If no unit is given the value is assumed to be in nanoseconds. Supported units are: ms, s, hz (case insensitive)

For example: “10000000”, “10ms”, “1s”, “50Hz”.

Using std::string as the first parameter of make_condition<T> is only available through Arg.

For example: Arg("recess_period") = "1s" or Arg("recess_period", "1s").

The recess (pause) period can also be specified as an integer value (type int64_t) in nanoseconds or as a value of type std::chrono::duration<Rep, Period> (see


  • 1000 (1000 nanoseconds == 1 microsecond)

  • 5ns, 10us, 1ms, 0.5s, 1min, 0.5h, etc.

    • requires #include <chrono> and using namespace std::chrono_literals;

  • std::chrono::milliseconds(10)

  • std::chrono::duration<double, std::milli>(10)

  • std::chrono::duration<double, std::ratio<1, 1000>>(10)

This class wraps GXF SchedulingTerm(nvidia::gxf::PeriodicSchedulingTerm).

Public Functions

template<typename ArgT, typename ...ArgsT, typename = std::enable_if_t<!std::is_base_of_v<::holoscan::Condition, std::decay_t<ArgT>> && (std::is_same_v<::holoscan::Arg, std::decay_t<ArgT>> || std::is_same_v<::holoscan::ArgList, std::decay_t<ArgT>>)>>
inline PeriodicCondition(ArgT &&arg, ArgsT&&... args)

PeriodicCondition() = default

explicit PeriodicCondition(int64_t recess_period_ns)

template<typename Rep, typename Period>
inline explicit PeriodicCondition(std::chrono::duration<Rep, Period> recess_period_duration)

PeriodicCondition(const std::string &name, nvidia::gxf::PeriodicSchedulingTerm *term)

inline virtual const char *gxf_typename() const override

virtual void setup(ComponentSpec &spec) override

Define the condition specification.


spec – The reference to the component specification.

void recess_period(int64_t recess_period_ns)

Set recess period.

Note that calling this method doesn’t affect the behavior of the condition once the condition is initialized.


recess_period_ns – The integer representing recess period in nanoseconds.

template<typename Rep, typename Period>
inline void recess_period(std::chrono::duration<Rep, Period> recess_period_duration)

Set recess period.

Note that calling this method doesn’t affect the behavior of the condition once the condition is initialized.


recess_period_duration – The recess period of type std::chrono::duration.

int64_t recess_period_ns()

Get recess period in nano seconds.


The minimum time which needs to elapse between two executions (in nano seconds)

int64_t last_run_timestamp()

Get the last run time stamp.


The last run time stamp.

nvidia::gxf::PeriodicSchedulingTerm *get() const

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