-----Original Message----- From: Steven Rostedt <rostedt@xxxxxxxxxxx> Sent: Tuesday, May 12, 2020 4:36 PM To: Elana Copperman <Elana.Copperman@xxxxxxxxxxxx> Cc: linux-rt-users <linux-rt-users@xxxxxxxxxxxxxxx>; Thomas Gleixner <tglx@xxxxxxxxxxxxx>; Vladimir Kondratiev (Mobileye) <63dc4b5d-c467-4bfb-bce5-74485907c850@xxxxxxxxxxxxxxxxxxxxxxxxxx> Subject: Re: cgroups CPU time management + PREEMPT_RT On Tue, 12 May 2020 13:30:27 +0000 Elana Copperman <Elana.Copperman@xxxxxxxxxxxx> wrote: > Hi, can you help to clarify if there is any implementation support or > evidence on configuring cgroups CPU time allocations for RT tasks in > conjunction with the PREEMPT_RT patch? What exactly are you trying to do with cgroups CPU time allocations, and what is the problem you are seeing with the PREEMPT_RT patch with them? I'm assuming you are using the 5.6-rt kernel. >> No, we are using version 4.19.72 + PREEMPT_RT patch >> We are still in design stage. Just trying to understand how to reconcile the requirements. >> Currently we actually see no justification for using cgroups CPU time allocations for RT tasks, unless you have some specific support in more recent versions of the patch or kernel -- Steve > > Or are the two requirements contradictory in essence and not jointly > feasible? > > Thanks > > Elana and Vladimir > > > > > From: Elana Copperman > > Sent: Thursday, May 7, 2020 10:08 PM > > To: linux-rt-users <linux-rt-users@xxxxxxxxxxxxxxx>; Vladimir > Kondratiev > (Mobileye) > <63dc4b5d-c467-4bfb-bce5-74485907c850@xxxxxxxxxxxxxxxxxxxxxxxxxx> > > Subject: RE: cgroups CPU time management + PREEMPT_RT > > > > > Hi, > > We are new to the mailing list, and new to PREEMPT_RT. > > We are working on a project with a safety requirement to configure > cgroups for resource management, as well as functional requirement for > deployment of PREEMPT_RT patch. > > cgroups in general can be used in this context, in particular for > managing resources such as memory; and even for managing CPU time for > non-RT tasks. > > > However, we do see a potential problem with RT tasks, and how the CPU > controller would work with the RT scheduling. > > There is some obvious concern here, and this seems to be backed by > what I find online regarding this question. > > > > Can you help us to clarify what is the current state of > implementation, and if there is any support for cgroup CPU controller > configuration to work effectively with PREEMPT_RT for RT tasks? > > > Thanks > > Elana > > > > >
