On 06/29/2011 07:20 AM, Michal Hocko wrote: > Hi, > > On Thu 23-06-11 19:10:39, Kevin Constantine wrote: >> On 06/23/2011 05:51 PM, Balbir Singh wrote: >>> If you don't mind, can I ask how you are using libcgroup, what is the use >>> case? >>> >> >> We're using cgroups in our render environment to pin batch jobs and >> their child processes to individual cpu's to avoid processes hopping >> around to different cores and flushing their caches. Basically each >> batch job gets its own cgroup with the cpuset controller and we allocate >> a single cpu to that cgroup. >> >> We're also using them to run batch jobs on our interactive workstations >> without impacting the end user. We're carving off a few cores and a few >> GB's of RAM from each workstation to run batch jobs on throughout the day. >> >> Basically the batch scheduler is dynamically creating and destroying >> cgroups pretty regularly. I wrote code to do all of that and then >> realized that libcgroup exists, so now I'm going back through and >> refactoring to use the api as much as possible. > > I am wondering why you need to write any code for that. Isn't cgred > (man cgrules.conf) what you need? >
I think cgred makes sense for managing machines where I know what kind of workload to expect. My understanding of it is that cgroups are created ahead of time with cgconfig.conf and then the rules map processes into those cgroups. The problem is that I have no idea what kind of workload to expect on most of these machines. The processes could be named just about anything, and they could come from just about any user. I could set up a config so that anything that gets run from the scheduler's client daemon process lands in a cgroup. But then we run into the situation where I want each batch process to live in its own cgroup and have one or more cpu's pinned to that cgroup (depending on how many cpu's the job asks for). I'm not sure how to configure something dynamic like that with these rules. It seems easier to add cgroup functionality to the scheduler than it does to come up with some configuration management scheme for creating and maintaining cgrules.conf files all over the place. cgconfig/cgred feels like something that you'd set up and kind of forget about on a server where I've got an ftp service and an email service and want to keep them in resource boxes. In our environment, rules might change depending on what time of day it is. For example, at night the memory and number of cpus allocated to batch jobs on a machine might get increased since there's very little interactive work happening. -kevin ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 _______________________________________________ Libcg-devel mailing list Libcg-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libcg-devel
