Lachlan regarding stress-ng --cpu 5 This is starting 5 workers (threads). It will be contained within a cgroup here, and allocated some cores/threads. You can start as many workers/threads as you like within a cgroup. There is no signalling back between stress-ng and the cgroup setup! (If I am wrong forgive me)
Also top is your friend here. And more usefully 'htop' Just look at top with the flag to show threads -H and 'j' to show last used cpu On 14 August 2017 at 08:12, John Hearns <[email protected]> wrote: > Lachlan, forgive me if I am teaching granny to suck eggs..,, > I have recently been workign with cgroups. > If you run an interactive job what do you see when cat /proc/self/cgroups > Also have you explored in /sys/fs/cgroups and checked what resources are > in the cgroups which a job has? > > On 14 August 2017 at 07:49, Lachlan Musicman <[email protected]> wrote: > >> Hola, >> >> Slurm is complicated software, and sometimes the docs can be dense - I'm >> looking for some clarification please. >> >> We have a system set up with Threads as CPUs. 1 socket, 4 cores, 2 >> threads = 8 cpus >> >> I would like to implement CGroups because some of our users are quite >> happy to utilise all threads despite other users. >> >> We have TaskPlugin=task/cgroup and when testing I noticed that the # of >> threads/cpus being allocated was rounded up to the nearest even. I presume >> this was due to cgroups marking a core as a cpu, rather than a thread as a >> cpu. >> >> So I set TaskPluginParam=Threads, but slurm is still allowing the use of >> more threads than have been requested. >> >> In particular, I'm running this test: >> >> #!/bin/bash >> #SBATCH --nodes=1 >> #SBATCH --ntasks=3 >> >> stress-ng --cpu 5 --cpu-method all --io 5 --vm 1 --vm-bytes 1G --timeout >> 600s --quiet >> >> >> I was hoping that the cgroup would kill the job because of too many cpus, >> but that's not how stress-ng works I've discovered. >> >> Regardless, when running this, I noted that squeue shows I've been >> allocated 3 CPUs, but on the server itself, I'm seeing four cpus being used? >> >> What have I done wrong? Is it possible to have granular control at the >> thread level with cgroups? >> >> cheers >> L. >> >> >> ------ >> "The antidote to apocalypticism is *apocalyptic civics*. Apocalyptic >> civics is the insistence that we cannot ignore the truth, nor should we >> panic about it. It is a shared consciousness that our institutions have >> failed and our ecosystem is collapsing, yet we are still here — and we are >> creative agents who can shape our destinies. Apocalyptic civics is the >> conviction that the only way out is through, and the only way through is >> together. " >> >> *Greg Bloom* @greggish https://twitter.com/greggish/s >> tatus/873177525903609857 >> > >
