Re: [PATCH 0/4] x86: Add Cache QoS Monitoring (CQM) support
From: Peter Zijlstra
Date: Mon Jan 06 2014 - 06:08:29 EST
On Fri, Jan 03, 2014 at 12:34:41PM -0800, Peter P Waskiewicz Jr wrote:
> The CPU features themselves are relatively straight-forward, but
> the presentation of the data is less straight-forward. Since this
> tracks cache usage and occupancy per process (by swapping Resource
> Monitor IDs, or RMIDs, when processes are rescheduled), perf would
> not be a good fit for this data, which does not report on a
> per-process level. Therefore, a new cgroup subsystem, cacheqos, has
> been added. This operates very similarly to the cpu and cpuacct
> cgroup subsystems, where tasks can be grouped into sub-leaves of the
> root-level cgroup.
This doesn't make any sense.. From a quick SDM read you can do pretty
much whatever with those RMIDs. If you allocate a RMID per task (thread
in userspace) you can actually measure things on a task basis.
>From then on you can use perf-cgroup to group whatever tasks you want.
So please be more explicit in why you think this doesn't fit into perf.
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