Re: [gentoo-user] Re: gigabyte mobo latency

[thegeezer <thegeezer@thegeezer.net>]

On 19/10/14 04:15, James wrote:
> thegeezer <thegeezer <at> thegeezer.net> writes:
>
>
>> there is a little more here
>> http://gentoo-en.vfose.ru/wiki/Improve_responsiveness_with_cgroups
>> which will allow you to script creating a cgroup with the processID of
>> an interactive shell, that you can start from to help save hunting down
>> all the threads spawned by chrome.
>> you can then do fun stuff with echo $$ >
>> /sys/fs/cgroup/cpu/high_priority/tasks
> Yea this is cool. But when it's a cluster, with thousands of processes
cgroups are hierarchical, so for example if you start a bash script
which is in cgroup "cpu/high_prio" which then starts your processes, all
called programs go into the same cgroup which makes it a bit simpler.
also openrc will start your services in the correct cgroup too
> this seem to be limited by the manual parsing and CLI actions that
> are necessary for large/busy environments. (We shall see).
>
>> hopefully this will give you a bit more control over all of that though
>
> Gmane mandates that the previous lines be culled. That said; you have given
> me much to think about, test and refine. 
>
> In /sys/fs/cgroup/cpu   I have:
>
> cgroup.clone_children  cgroup.procs  cpu.shares      release_agent
> cgroup.event_control cgroup.sane_behavior notify_on_release  tasks
>
> So I'll have to research creating and priotizing dirs like "high_priority"
>
>
> I certainly appreciate your lucid and direct explanations.
> Let me play with this a bit and I'll post back when I munge things
> up.....   Are there any "graphical tools" for adjusting and managing
> cgroups?  
i thought that htop did this but i was wrong.. it only shows which
cgroup processes are in. that would be a killer feature though.
> Surely when I apply this to the myriad of things running
> on my mesos+spark cluster I'm going to need a well thoughout tool
> for cgroup management, 
especially for non-local systems.  other distros have apps such as
"cgclassify" which provides some shortcut to managing cgroups --
creation / and moving process in and out
you can also have a nohup process that does ps -eLf to search for
process you want to classify and move them into the appropriate cgroup  
for default cgroups you can also use inotify
a quick search shows http://libcg.sourceforge.net/ which daemonises this
process.
all this is a bit hack'n'slash though i appreciate, so if anyone else
knows of suitable tools i'd also be interested to hear of them    
> particularly on memory resources organization
> and allocations as spark is an "in_memory" environment that seems 
> sensitive to OOM issues of all sorts.
>
> thx,
> James
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