On 2015/08/19 5:31, Tejun Heo wrote:
Hello, Paul.
On Mon, Aug 17, 2015 at 09:03:30PM -0700, Paul Turner wrote:
2) Control within an address-space. For subsystems with fungible resources,
e.g. CPU, it can be useful for an address space to partition its own
threads. Losing the capability to do this against the CPU controller would
be a large set-back for instance. Occasionally, it is useful to share these
groupings between address spaces when processes are cooperative, but this is
less of a requirement.
This is important to us.
Sure, let's build a proper interface for that. Do you actually need
sub-hierarchy inside a process? Can you describe your use case in
detail and why having hierarchical CPU cycle distribution is essential
for your use case?
An actual per-thread use case in our customers is qemu-kvm + cpuset.
customers pin each vcpus and qemu-kvm's worker threads to cpus.
For example, pinning 4 vcpus to cpu 2-6 and pinning qemu main thread and
others(vhost) to cpu 0-1.
This is an actual kvm tuning on our customers for performance guarantee.
In another case, cpu cgroup's throttling feature is used per vcpu for vm cpu
sizing.
Thanks,
-Kame
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