126 lines
4.1 KiB
Plaintext
126 lines
4.1 KiB
Plaintext
#
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# For a description of the syntax of this configuration file,
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# see the file kconfig-language.txt in the NuttX tools repository.
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#
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menu "Common I/O Buffer Support"
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config MM_IOB
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bool "Enable generic I/O buffer support"
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default n
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---help---
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This setting will build the common I/O buffer (IOB) support
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library.
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if MM_IOB
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config IOB_NBUFFERS
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int "Number of pre-allocated I/O buffers"
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default 36 if NET_WRITE_BUFFERS
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default 24 if !NET_WRITE_BUFFERS && NET_READAHEAD
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default 8 if !NET_WRITE_BUFFERS && !NET_READAHEAD
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---help---
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Each packet is represented by a series of small I/O buffers in a
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chain. This setting determines the number of preallocated I/O
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buffers available for packet data.
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config IOB_BUFSIZE
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int "Payload size of one I/O buffer"
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default 196
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---help---
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Each packet is represented by a series of small I/O buffers in a
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chain. This setting determines the data payload each preallocated
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I/O buffer.
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config IOB_HEADSIZE
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int "Head size of each I/O buffer"
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default 0
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---help---
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This setting determines the reserved size in front of the payload
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buffer in each I/O buffer.
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config IOB_ALIGNMENT
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int "Alignment size of each I/O buffer"
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default 4
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---help---
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The member io_head of all I/O buffers is aligned to the value
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specified by this configuration.
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config IOB_SECTION
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string "The section where iob buffer is located"
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---help---
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The section where iob buffer is located.
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The section must be zero-initialized on system boot.
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config IOB_NCHAINS
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int "Number of pre-allocated I/O buffer chain heads"
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default 0 if !NET_READAHEAD
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default IOB_NBUFFERS if NET_READAHEAD
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---help---
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These tiny nodes are used as "containers" to support queueing of
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I/O buffer chains. This will limit the number of I/O transactions
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that can be "in-flight" at any give time. The default value of
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zero disables this features.
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These generic I/O buffer chain containers are not currently used
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by any logic in NuttX. That is because their other specialized
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I/O buffer chain containers that also carry a payload of usage
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specific information.
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Note: TCP doesn't use this.
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Note: UDP and CAN use this.
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config IOB_THROTTLE
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int "I/O buffer throttle value"
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default 0 if !NET_WRITE_BUFFERS || !NET_READAHEAD
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default 8 if NET_WRITE_BUFFERS && NET_READAHEAD
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---help---
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TCP write buffering and read-ahead buffer use the same pool of free
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I/O buffers. In order to prevent uncontrolled incoming TCP packets
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from hogging all of the available, pre-allocated I/O buffers, a
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throttling value is required. This throttle value assures that
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I/O buffers will be denied to the read-ahead logic before TCP writes
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are halted.
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config IOB_NOTIFIER
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bool "Support IOB notifications"
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default n
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depends on SCHED_WORKQUEUE
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select WQUEUE_NOTIFIER
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---help---
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Enable building of IOB notifier logic that will execute a worker
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function on the high priority work queue when an IOB is available.
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This is is a general purpose notifier, but was developed specifically to
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support poll() logic where the poll must wait for an IOB to become
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available.
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config IOB_NOTIFIER_DIV
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int "Notification divider"
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default 4
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range 1 64
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depends on IOB_NOTIFIER
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---help---
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IOBs may become available at very high rates and the resulting
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notification processing can be substantial even if there is nothing
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waiting for a free IOB. This divider will reduce that rate of
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notification. This must be an even power of two. Supported values
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include: 1, 2, 4, 8, 16, 32, 64. The default value of 4 means that
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a notification will be sent only when there are a multiple of 4 IOBs
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available.
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config IOB_DEBUG
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bool "Force I/O buffer debug"
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default n
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depends on DEBUG_FEATURES && !SYSLOG_BUFFER
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---help---
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This option will force debug output from I/O buffer logic. This
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is not normally something that would want to do but is convenient
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if you are debugging the I/O buffer logic and do not want to get
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overloaded with other un-related debug output.
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NOTE that this selection is not available if IOBs are being used
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to syslog buffering logic (CONFIG_SYSLOG_BUFFER=y)!
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endif # MM_IOB
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endmenu # Common I/O buffer support
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