9/9: cpu_docs Documentation how to use the CPU controller
Signed-off-by: MAEDA Naoaki <[EMAIL PROTECTED]> Signed-off-by: Kurosawa Takahiro <[EMAIL PROTECTED]> Documentation/res_groups/cpurc | 72 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 72 insertions(+) Index: linux-2.6.17-rc3/Documentation/res_groups/cpurc =================================================================== --- /dev/null +++ linux-2.6.17-rc3/Documentation/res_groups/cpurc @@ -0,0 +1,73 @@ +Introduction +------------ + +CPU resource controller enables user/sysadmin to control CPU time +percentage of tasks in a resouce group. It controls time_slice of tasks based on +the feedback of difference between the target value and the current usage +in order to control the percentage of the CPU usage to the target value. + +Installation +------------ + +1. Configure "CPU Resource Controller" under RES_GROUPS. Currently, this cannot +be configured as a module. + +2. Reboot the system with the new kernel. + +3. Verify that the CPU resource controller is present by reading +the file /config/res_groups/shares (should show a line with res=cpu). + +Assigning shares +---------------- + +Follows the general approach of setting shares for a resource group in Resource +Groups. + +# echo "res=cpu,min_shares=val" > shares + +sets the min_shares of a resource group. + +The CPU resource controller calculates an effective min_shares in percent +for each resoruce group. Following is an example of resource groups/min_shares +settings and each effective min_shares. + + / + effective_min_shares + = 100% - 50% - 30% + = 20% + +---------------+---------------+ + /A min_shares=50% /B min_shares=30% + effective_min_shares effective_min_shares + = 50% - 10% - 25% = 30% - 0% + = 15% = 30% ++---------------+---------------+ +/C min_shares=20% /D min_shares=50% +effective_min_shares effective_min_shares += 20% of 50% - 0% = 10% = 50% of 50% - 0 % += 10% = 25% + +If the min_shares in the resource group /A is changed 50% to 40% in the above +example, the effective_min_shares of the resource group /A, /C and /D are +automatically changed to 12%, 8% and 20% respectively. + +Although the child_shares_divisor can be changed, the effective_min_shares is +always calculated in percent. + +Note that the CPU resource controller doesn't support the limit, so assigning +the limit for "res=cpu" will have no effect. + +Monitoring +---------- + +stats file shows the effective min_shares and the current cpu usage of a resouce +group in percentage. + +# cat stats +cpu:effective_min_shares=50, load=40 + +That means the effective min_shares of the resource group is 50% and the current +load average of the resource group is 40%. + +Since the tasks in the resource group do not always try to consume CPU, +the load could be less or greater than the effective_min_shares. Both cases +are normal. ------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ ckrm-tech mailing list https://lists.sourceforge.net/lists/listinfo/ckrm-tech
