理解和优化进程与线程状态转换机制

Within Cisco IOS XR there are servers who provide the services and clients who use the services. A particular process can have a number of threads who provide the same service. Another process can have a number of clients that might require a particular service at any point in time. Access to the servers is not always available, and if a client request access to a service it sits there and waits for the server to be free. In this case the client is said to be blocked. This is called a blocking client server model. The client might be blocked because it waits for a resource such as a MUTEX, or due to the fact that the server has not yet replied.

Issue a show process ospf command in order to check the status of the threads in the ospf process:

RP/0/RP1/CPU0:CWDCRS#show process ospf
Job Id: 250
PID: 110795
Executable path: /disk0/hfr-rout-3.2.3/bin/ospf
Instance #: 1
Version ID: 00.00.0000
Respawn: ON
Respawn count: 1
Max. spawns per minute: 12
Last started: Tue Jul 18 13:10:06 2006
Process state: Run
Package state: Normal
Started on config: cfg/gl/ipv4-ospf/proc/101/ord_a/routerid
core: TEXT SHAREDMEM MAINMEM
Max. core: 0
Placement: ON
startup_path: /pkg/startup/ospf.startup
Ready: 1.591s
Available: 5.595s
Process cpu time: 89.051 user, 0.254 kernel, 89.305 total
JID TID Stack pri state HR:MM:SS:MSEC NAME
250 1 40K 10 Receive 0:00:11:0509 ospf
250 2 40K 10 Receive 0:01:08:0937 ospf
250 3 40K 10 Receive 0:00:03:0380 ospf
250 4 40K 10 Condvar 0:00:00:0003 ospf
250 5 40K 10 Receive 0:00:05:0222 ospf

Note that ospf process is given a Job ID (JID), which is 250. This never changes on a running router and generally on a particular version of Cisco IOS XR. Within the ospf process there are five threads each with their own Thread ID (TID). Listed is the stack space for each thread, the priority of each thread and its state.

好好学习，天天向上！