<meta http-equiv="content-type" content="text/html; charset=utf-8">Hi Lennart,<div>Thanks for the explanation.</div><div><br></div><div>IMHO, To re-enable user session 'cpu' sorting:</div><div>a) Desktop distributions disable GROUP_RT in the kernel, then no rt_bandwidth, all RT-apps can be fully administrated under rtkit.</div>
<div><br></div><div>Or b) cpu cgroup controller should default make sub-cgroups share rt_bandwidth with their parent.</div><div>Internally, kernel uses two separate hierarchies for NORMAL and RT processes, current logic should be changed as: a new cgroup with a cpu controller will add a new level in 'NORMAL hierarchy', but not touch 'RThierarchy' unless set sched_rt_runtime_us.</div>
<meta http-equiv="content-type" content="text/html; charset=utf-8"><meta http-equiv="content-type" content="text/html; charset=utf-8"><meta http-equiv="content-type" content="text/html; charset=utf-8"><div><br><br><div class="gmail_quote">
2011/2/14 Lennart Poettering <span dir="ltr"><<a href="mailto:lennart@poettering.net">lennart@poettering.net</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">On Fri, 11.02.11 10:30, <a href="mailto:fykcee1@gmail.com">fykcee1@gmail.com</a> (<a href="mailto:fykcee1@gmail.com">fykcee1@gmail.com</a>) wrote:<br>
<br>
> Hi Lennart, Andrey,<br>
><br>
> Some questions about the discuss:<br>
> 1. Does systemd re-enable sorting user sessions into their own cgroups in<br>
> the 'cpu' hierarchy?<br>
<br>
</div>No, we cannot reenable that before the cpu cgroup controller gets fixed.<br>
<br>
On current kernels doing this kind of sorting means practically that all<br>
processes we sort into a 'cpu' cgroup lose their capability to use RT<br>
scheduling.<br>
<br>
I am not aware of any typical daemon we ship that would use RT<br>
scheduling hence we are keeping the default 'cpu' cgroup sorting for<br>
system daemons enabled. However user applications are more likely to use<br>
RT (for example PA does) and hence we have disabled this for sessions<br>
for now.<br>
<div class="im"><br>
> 2. AIUI, rtkit is a daemon used for doing RT-related privilege operations.<br>
> It doesn't spawn RT-threads. Am I right?<br>
<br>
</div>It does use RT privs for the implementatin of the canary watchdog.<br>
<div class="im"><br>
> 3. Does rtkit have related systemd service file? Does it run at its own<br>
> cgroup with controller=cpu? If yes, how does the cgroup receive<br>
> rt-bandwidth(period time, run time)?<br>
<br>
</div>rtkit comes with a systemd unit file. In rtkit git this unit file<br>
ensures that rtkit is explicitly moved into the root "cpu" cgroup so<br>
that it can make use of RT scheduling -- if you so will rtkit is the one<br>
exception to what i mentioned above regarding no system daemons using<br>
RT.<br>
<div><div></div><div class="h5"><br>
Lennart<br>
<br>
--<br>
Lennart Poettering - Red Hat, Inc.<br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>Regards,<div><br><div>- cee1</div></div><br>
</div>