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# ====================================================================

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#      counters.cdl

#

#      configuration data related to the kernel counters and clocks

#

# ====================================================================

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# ====================================================================

######DESCRIPTIONBEGIN####

#

# Author(s):      jskov

# Original data:  nickg

# Contributors:

# Date:           1999-07-05

#

#####DESCRIPTIONEND####

#

# ====================================================================

cdl_option CYGVAR_KERNEL_COUNTERS_CLOCK {

    display       "Provide real-time clock"

    requires      CYGIMP_KERNEL_INTERRUPTS_DSRS

    default_value 1

    description   "

        On all current target systems the kernel can provide a

        real-time clock. This clock serves two purposes. First it is

        necessary to support clock and alarm related functions.

        Second it is needed to implement timeslicing in some of the

        schedulers including the mlqueue scheduler. If the

        application does not require any of these facilities then it

        is possible to disable the real time clock support

        completely."

}

cdl_option CYGNUM_KERNEL_COUNTERS_CLOCK_ISR_PRIORITY {

    display             "Interrupt priority for the real-time clock"

    active_if           CYGVAR_KERNEL_COUNTERS_CLOCK

    flavor              data

    default_value       { is_loaded(CYGNUM_HAL_KERNEL_COUNTERS_CLOCK_ISR_DEFAULT_PRIORITY) ?

                              CYGNUM_HAL_KERNEL_COUNTERS_CLOCK_ISR_DEFAULT_PRIORITY : 1 }

    description "

        The implementation of the kernel's real-time clock typically

        involves installing an interrupt handler on a suitable hardware

        timer. This option controls the priority level used for that

        interrupt. On most platforms the value is not important because

        the clock ISR leaves most of the work to be done by the DSR.

        However some processors have interrupt controllers with special

        requirements for the interrupt priorities, in which case

        application developers must be able to manipulate the clock's

        priority."

}

cdl_interface CYGINT_KERNEL_COUNTERS {

    requires 1 == CYGINT_KERNEL_COUNTERS

    no_define

}

# NOTE: these option should really be a single enum.

cdl_option CYGIMP_KERNEL_COUNTERS_SINGLE_LIST {

    display       "Implement counters using a single list"

    default_value 1

    implements    CYGINT_KERNEL_COUNTERS

    description "

        There are two different implementations of the counter

        objects. The first implementation stores all alarms in a

        single linked list. The alternative implementation uses a

        table of linked lists. A single list is more efficient in

        terms of memory usage and is generally adequate when the

        application only makes use of a small number of alarms."

}

cdl_component CYGIMP_KERNEL_COUNTERS_MULTI_LIST {

    display       "Implement counters using a table of lists"

    default_value 0

    implements    CYGINT_KERNEL_COUNTERS

    description   "

        There are two different implementations of the counter

        objects. The first implementation stores all alarms in a

        single linked list. The alternative implementation uses a

        table of linked lists, with the size of the table being a

        separate configurable option. For more complicated

        operations it is better to have a table of lists since this

        reduces the amount of computation whenever the timer goes

        off. Assuming a table size of 8 (the default value) on

        average the timer code will only need to check 1/8 of the

        pending alarms instead of all of them."

    cdl_option CYGNUM_KERNEL_COUNTERS_MULTI_LIST_SIZE {

        display       "Size of counter list table"

        flavor        data

        legal_values  1 to 1024

        default_value 8

        description   "

            If counters are implemented using an array of linked lists

            then this option controls the size of the array. A larger

            size reduces the amount of computation that needs to take

            place whenever the timer goes off, but requires extra

            memory."

    }

}

cdl_option CYGIMP_KERNEL_COUNTERS_SORT_LIST {

    display       "Sort the counter list"

    default_value 0

    description   "

        Sorting the counter lists reduces the amount of work that

        has to be done when a counter tick is processed, since the

        next alarm to expire is always at the front of the list.

        However, it makes adding an alarm to the list more expensive

        since a search must be done for the correct place to put it.

        Many alarms are used to implement timeouts, which seldom trigger,

        so it is worthwhile optimizing this case. For this reason

        sorted list are disabled by default."

}

cdl_option CYGVAR_KERNEL_COUNTERS_CLOCK_LATENCY {

    display       "Measure real-time \[clock\] interrupt latency"

    requires      CYGVAR_KERNEL_COUNTERS_CLOCK

    default_value 0

    description   "

    Measure the interrupt latency as seen by the real-time clock

    timer interrupt.  This requires hardware support, defined by

    the HAL_CLOCK_LATENCY() macro."

}

cdl_option CYGVAR_KERNEL_COUNTERS_CLOCK_DSR_LATENCY {

    display       "Measure real-time \[clock\] DSR latency"

    requires      CYGVAR_KERNEL_COUNTERS_CLOCK_LATENCY

    default_value CYGVAR_KERNEL_COUNTERS_CLOCK_LATENCY

    description   "

          Measure the DSR latency as seen by the real-time clock

          timer interrupt.  This requires hardware support, defined by

          the HAL_CLOCK_LATENCY() macro."

}

cdl_option CYGNUM_KERNEL_COUNTERS_RTC_RESOLUTION {

    display       "RTC resolution"

    flavor        data

    calculated    {"{CYGNUM_HAL_RTC_NUMERATOR, CYGNUM_HAL_RTC_DENOMINATOR}"}

    description   "

        This option automatically defines the tuple which is used to

        initialize the RTC resolution, consisting of a numerator and

        denominator. The values of the numerator and denominator are

        defined by the HAL."

}

cdl_option CYGNUM_KERNEL_COUNTERS_RTC_PERIOD {

    display       "RTC period"

    flavor        data

    calculated    {"CYGNUM_HAL_RTC_PERIOD"}

    description   "

        This option defines the RTC period to be used in

        setting the system clock hardware. It is essentially

        an alias for CYGNUM_HAL_RTC_PERIOD, which is defined

        in the HAL."

}

# EOF counters.cdl