counters.cdl

eCos操作系统源码

# ====================================================================
#
#      counters.cdl
#
#      configuration data related to the kernel counters and clocks
#
# ====================================================================
#####ECOSGPLCOPYRIGHTBEGIN####
## -------------------------------------------
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## Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
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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_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