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Update some Kconfig comments; Add a upper limit on the lower priority worker thread for priority inheritance

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This commit is contained in:
Gregory Nutt 2014-10-07 17:11:26 -06:00
parent 792e40f513
commit 7f36c4e97b
3 changed files with 109 additions and 9 deletions
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27
include/nuttx/wqueue.h
View File

@ -79,8 +79,10 @@
* then an additional, lower-priority work queue will also be created. This
* lower priority work queue is better suited for more extended processing
* (such as file system clean-up operations)
* CONFIG_SCHED_LPWORKPRIORITY - The execution priority of the lower priority
* worker thread. Default: 50
* CONFIG_SCHED_LPWORKPRIORITY - The minimum execution priority of the lower
* priority worker thread. Default: 50
* CONFIG_SCHED_LPWORKPRIOMAX - The maximum execution priority of the lower
* priority worker thread. Default: 176
* CONFIG_SCHED_LPWORKPERIOD - How often the lower priority worker thread
* checks for work in units of microseconds. Default: 50*1000 (50 MS).
* CONFIG_SCHED_LPWORKSTACKSIZE - The stack size allocated for the lower
@ -175,6 +177,27 @@
# define CONFIG_SCHED_LPWORKPRIORITY 50
# endif
# ifndef CONFIG_SCHED_LPWORKPRIOMAX
# ifdef CONFIG_SCHED_HPWORK
# define CONFIG_SCHED_LPWORKPRIOMAX (CONFIG_SCHED_WORKPRIORITY-16)
# else
# define CONFIG_SCHED_LPWORKPRIOMAX 176
# endif
# endif
# ifdef CONFIG_SCHED_HPWORK
# if CONFIG_SCHED_LPWORKPRIORITY >= CONFIG_SCHED_WORKPRIORITY
# error CONFIG_SCHED_LPWORKPRIORITY >= CONFIG_SCHED_WORKPRIORITY
# endif
# if CONFIG_SCHED_LPWORKPRIOMAX >= CONFIG_SCHED_WORKPRIORITY
# error CONFIG_SCHED_LPWORKPRIOMAX >= CONFIG_SCHED_WORKPRIORITY
# endif
# endif
# if CONFIG_SCHED_LPWORKPRIORITY > CONFIG_SCHED_LPWORKPRIOMAX
# error CONFIG_SCHED_LPWORKPRIORITY > CONFIG_SCHED_LPWORKPRIOMAX
# endif
# ifndef CONFIG_SCHED_LPWORKPERIOD
# define CONFIG_SCHED_LPWORKPERIOD (50*1000) /* 50 milliseconds */
# endif

77
libc/Kconfig
View File

@ -412,9 +412,10 @@ config SCHED_HPWORK
bool "High priority (kernel) worker thread"
default y
---help---
If SCHED_WORKQUEUE is defined, then a single, high priority work queue is
created by default. This high priority worker thread is intended to serve
as the "bottom half" for driver interrupt handling.
If SCHED_WORKQUEUE is defined, then a single, high priority work
queue is created by default. This high priority worker thread is
intended to serve as the "bottom half" for driver interrupt
handling.
if SCHED_HPWORK
@ -422,7 +423,20 @@ config SCHED_WORKPRIORITY
int "High priority worker thread priority"
default 192
---help---
The execution priority of the worker thread. Default: 192
The execution priority of the higher priority worker thread.
The higher priority worker thread is intended to serve as the
"bottom" half for device drivers. As a consequence it must run at
a very high, fixed priority. Typically, it should be the highest
priority thread in your system. Default: 192
For lower priority, application oriented worker thread support,
please consider enabling the lower priority work queue. The lower
priority work queue runs at a lower priority, of course, but has
the added advantage that it supports "priority inheritance" (if
PRIORITY_INHERITANCE is also selected): The priority of the lower
priority worker thread can then be adjusted to match the highest
priority client.
config SCHED_WORKPERIOD
int "High priority worker thread period"
@ -445,8 +459,9 @@ config SCHED_LPWORK
If SCHED_WORKQUEUE is defined, then a single work queue is created by
default. If SCHED_LPWORK is also defined then an additional, lower-
priority work queue will also be created. This lower priority work
queue is better suited for more extended processing (such as file system
clean-up operations)
queue is better suited for more extended, application oriented
processing (such as file system clean-up operations or asynchronous
I/O)
if SCHED_LPWORK
@ -454,7 +469,55 @@ config SCHED_LPWORKPRIORITY
int "Low priority worker thread priority"
default 50
---help---
The execution priority of the lopwer priority worker thread. Default: 50
The minimum execution priority of the lower priority worker thread.
The lower priority worker thread is intended support application-
oriented functions. The lower priority work queue runs at a lower
priority, of course, but has the added advantage that it supports
"priority inheritance" (if PRIORITY_INHERITANCE is also selected):
The priority of the lower priority worker thread can then be
adjusted to match the highest priority client. Default: 50
NOTE: This priority inheritance feature is not automatic. The
lower priority worker thread will always a fixed priority unless
you implement logic that calls lpwork_boostpriority() to raise the
priority of the lower priority worker thread (typically called
before scheduling the work) and then call the matching
lpwork_restorepriority() when the work is completed (typically
called within the work handler at the completion of the work).
Currently, only the NuttX asynchronous I/O logic uses this dynamic
prioritization feature.
The higher priority worker thread, on the other hand, is intended
to serve as the "bottom" half for device drivers. As a consequence
it must run at a very high, fixed priority. Typically, it should
be the highest priority thread in your system.
config SCHED_LPWORKPRIOMAX
int "Low priority worker thread maximum priority"
default 176
depends on PRIORITY_INHERITANCE
---help---
The maximum execution priority of the lower priority worker thread.
The lower priority worker thread is intended support application-
oriented functions. The lower priority work queue runs at a lower
priority, of course, but has the added advantage that it supports
"priority inheritance" (if PRIORITY_INHERITANCE is also selected):
The priority of the lower priority worker thread can then be
adjusted to match the highest priority client.
The higher priority worker thread, on the other hand, is intended
to serve as the "bottom" half for device drivers. As a consequence
it must run at a very high, fixed priority. Typically, it should
be the highest priority thread in your system.
This function provides an upper limit on the priority of the lower
priority worker thread. This would be necessary, for example, if
the higher priority worker thread were to defer work to the lower
priority thread. Clearly, in such a case, you would want to limit
the maximum priority of the lower priority work thread. Default:
176
config SCHED_LPWORKPERIOD
int "Low priority worker thread period"

14
sched/wqueue/work_inherit.c
View File

@ -78,6 +78,13 @@ void lpwork_boostpriority(uint8_t reqprio)
irqstate_t flags;
pid_t wpid;
/* Clip to the configured maximum priority */
if (reqprio > CONFIG_SCHED_LPWORKPRIOMAX)
{
reqprio = CONFIG_SCHED_LPWORKPRIOMAX;
}
/* Get the process ID of the low priority worker thread from the low
* priority work queue. Then get the TCB of the low priority worker
* thread from the process ID.
@ -194,6 +201,13 @@ void lpwork_restorepriority(uint8_t reqprio)
int index;
int selected;
/* Clip to the configured maximum priority */
if (reqprio > CONFIG_SCHED_LPWORKPRIOMAX)
{
reqprio = CONFIG_SCHED_LPWORKPRIOMAX;
}
/* Get the process ID of the low priority worker thread from the low
* priority work queue. Then get the TCB of the low priority worker
* thread from the process ID.