!12 Specification NestOS Project Component Description File

From: @duyiwei7w 
Reviewed-by: @fu-shanqing 
Signed-off-by: @fu-shanqing

README.md

@@ -1,30 +1,73 @@
 # stalld
 
 #### 介绍
-The stalld program is a mechanism to prevent the starvation of operating system threads in a Linux system.
+The stalld program (which stands for 'stall daemon') is a
+mechanism to prevent the starvation of operating system threads in a
+Linux system. The premise is to start up on a housekeeping cpu (one
+that is not used for real-application purposes) and to periodically
+monitor the state of each thread in the system, looking for a thread
+that has been on a run queue (i.e. ready to run) for a specifed length
+of time without being run. This condition is usually hit when the
+thread is on the same cpu as a high-priority cpu-intensive task and
+therefore is being given no opportunity to run.
+When a thread is judged to be starving, stalld changes
+that thread to use the SCHED_DEADLINE policy and gives the thread a
+small slice of time for that cpu (specified on the command line). The
+thread then runs and when that timeslice is used, the thread is then
+returned to its original scheduling policy and stalld then
+continues to monitor thread states.
+There is now an experimental option to boost using SCHED_FIFO. This
+logic is used if the running kernel does not support the
+SCHED_DEADLINE policy and may be forced by using the -F/--force_fifo
+option.
+
 
-#### 软件架构
-软件架构说明
 
 
 #### 安装教程
 
-1.  xxxx
-2.  xxxx
-3.  xxxx
+Install stalld rpm package:
+
+yum install stalld
 
 #### 使用说明
+Logging options
 
-1.  xxxx
-2.  xxxx
-3.  xxxx
+-l/--log_only: only log information (do not boost) [false]
+-v/--verbose: print info to the std output [false]
+-k/--log_kmsg: print log to the kernel buffer [false]
+-s/--log_syslog: print log to syslog [true]
+
+
+Startup options
+
+-c/--cpu: list of cpus to monitor for stalled threads [all cpus]
+-f/--foreground: run in foreground [false but true when -v]
+-P/--pidfile: write daemon pid to specified file [no pidfile]
+
+
+Boosting options
+
+-p/--boost_period: SCHED_DEADLINE period [ns] that the starving task will receive [1000000000]
+-r/--boost_runtime: SCHED_DEADLINE runtime [ns] that the starving task will receive [20000]
+-d/--boost_duration: how long [s] the starving task will run with SCHED_DEADLINE [3]
+-F/--force_fifo: force using SCHED_FIFO for boosting
+
+
+Monitoring options
+
+-t/--starving_threshold: how long [s] the starving task will wait before being boosted [60]
+-A/--aggressive_mode: dispatch one thread per run queue, even when there is no starving
+threads on all CPU (uses more CPU/power). [false]
 
 #### 参与贡献
 
-1.  Fork 本仓库
-2.  新建 Feat_xxx 分支
-3.  提交代码
-4.  新建 Pull Request
+master分支使用最新的上游版本，如果检测到上游有最新版本发布，先形成issue后再提交对应PR更新，流程如下。
+1.  提交issue
+2.  Fork 本仓库
+3.  新建 Feat_xxx 分支
+4.  提交代码
+5.  新建 Pull Request
 
 
 #### 特技