Re: [PATCH v2 00/11] new cgroup controller for gpu/drm subsystem

Kenny Ho
2020-03-17T16:03:20Z

Hi Tejun,

What's your thoughts on this latest series?

Regards,
Kenny

On Wed, Feb 26, 2020 at 2:02 PM Kenny Ho <Kenny.Ho-5C7GfCeVMHo@public.gmane.org> wrote:
>
> This is a submission for the introduction of a new cgroup controller for the drm subsystem follow a series of RFCs [v1, v2, v3, v4]
>
> Changes from PR v1
> * changed cgroup controller name from drm to gpu
> * removed lgpu
> * added compute.weight resources, clarified resources being distributed as partitions of compute device
>
> PR v1: https://www.spinics.net/lists/cgroups/msg24479.html
>
> Changes from the RFC base on the feedbacks:
> * drop all drm.memory.* related implementation and focus only on buffer and lgpu
> * add weight resource type for logical gpu (lgpu)
> * uncoupled drmcg device iteration from drm_minor
>
> I'd also like to highlight the fact that these patches are currently released under MIT/X11 license aligning with the norm of the drm subsystem, but I am working to have the cgroup parts release under GPLv2 to align with the norm of the cgroup subsystem.
>
> RFC:
> [v1]: https://lists.freedesktop.org/archives/dri-devel/2018-November/197106.html
> [v2]: https://www.spinics.net/lists/cgroups/msg22074.html
> [v3]: https://lists.freedesktop.org/archives/amd-gfx/2019-June/036026.html
> [v4]: https://patchwork.kernel.org/cover/11120371/
>
> Changes since the start of RFC are as follows:
>
> v4:
> Unchanged (no review needed)
> * drm.memory.*/ttm resources (Patch 9-13, I am still working on memory bandwidth
> and shrinker)
> Base on feedbacks on v3:
> * update nominclature to drmcg
> * embed per device drmcg properties into drm_device
> * split GEM buffer related commits into stats and limit
> * rename function name to align with convention
> * combined buffer accounting and check into a try_charge function
> * support buffer stats without limit enforcement
> * removed GEM buffer sharing limitation
> * updated documentations
> New features:
> * introducing logical GPU concept
> * example implementation with AMD KFD
>
> v3:
> Base on feedbacks on v2:
> * removed .help type file from v2
> * conform to cgroup convention for default and max handling
> * conform to cgroup convention for addressing device specific limits (with major:minor)
> New function:
> * adopted memparse for memory size related attributes
> * added macro to marshall drmcgrp cftype private ?(DRMCG_CTF_PRIV, etc.)
> * added ttm buffer usage stats (per cgroup, for system, tt, vram.)
> * added ttm buffer usage limit (per cgroup, for vram.)
> * added per cgroup bandwidth stats and limiting (burst and average bandwidth)
>
> v2:
> * Removed the vendoring concepts
> * Add limit to total buffer allocation
> * Add limit to the maximum size of a buffer allocation
>
> v1: cover letter
>
> The purpose of this patch series is to start a discussion for a generic cgroup
> controller for the drm subsystem. The design proposed here is a very early
> one. We are hoping to engage the community as we develop the idea.
>
> Backgrounds
> ===========
> Control Groups/cgroup provide a mechanism for aggregating/partitioning sets of
> tasks, and all their future children, into hierarchical groups with specialized
> behaviour, such as accounting/limiting the resources which processes in a
> cgroup can access[1]. Weights, limits, protections, allocations are the main
> resource distribution models. Existing cgroup controllers includes cpu,
> memory, io, rdma, and more. cgroup is one of the foundational technologies
> that enables the popular container application deployment and management method.
>
> Direct Rendering Manager/drm contains code intended to support the needs of
> complex graphics devices. Graphics drivers in the kernel may make use of DRM
> functions to make tasks like memory management, interrupt handling and DMA
> easier, and provide a uniform interface to applications. The DRM has also
> developed beyond traditional graphics applications to support compute/GPGPU
> applications.
>
> Motivations
> ===========
> As GPU grow beyond the realm of desktop/workstation graphics into areas like
> data center clusters and IoT, there are increasing needs to monitor and
> regulate GPU as a resource like cpu, memory and io.
>
> Matt Roper from Intel began working on similar idea in early 2018 [2] for the
> purpose of managing GPU priority using the cgroup hierarchy. While that
> particular use case may not warrant a standalone drm cgroup controller, there
> are other use cases where having one can be useful [3]. Monitoring GPU
> resources such as VRAM and buffers, CU (compute unit [AMD's nomenclature])/EU
> (execution unit [Intel's nomenclature]), GPU job scheduling [4] can help
> sysadmins get a better understanding of the applications usage profile.
> Further usage regulations of the aforementioned resources can also help sysadmins
> optimize workload deployment on limited GPU resources.
>
> With the increased importance of machine learning, data science and other
> cloud-based applications, GPUs are already in production use in data centers
> today [5,6,7]. Existing GPU resource management is very course grain, however,
> as sysadmins are only able to distribute workload on a per-GPU basis [8]. An
> alternative is to use GPU virtualization (with or without SRIOV) but it
> generally acts on the entire GPU instead of the specific resources in a GPU.
> With a drm cgroup controller, we can enable alternate, fine-grain, sub-GPU
> resource management (in addition to what may be available via GPU
> virtualization.)
>
> In addition to production use, the DRM cgroup can also help with testing
> graphics application robustness by providing a mean to artificially limit DRM
> resources availble to the applications.
>
>
> Challenges
> ==========
> While there are common infrastructure in DRM that is shared across many vendors
> (the scheduler [4] for example), there are also aspects of DRM that are vendor
> specific. To accommodate this, we borrowed the mechanism used by the cgroup to
> handle different kinds of cgroup controller.
>
> Resources for DRM are also often device (GPU) specific instead of system
> specific and a system may contain more than one GPU. For this, we borrowed
> some of the ideas from RDMA cgroup controller.
>
> Approach
> ========
> To experiment with the idea of a DRM cgroup, we would like to start with basic
> accounting and statistics, then continue to iterate and add regulating
> mechanisms into the driver.
>
> [1] https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt
> [2] https://lists.freedesktop.org/archives/intel-gfx/2018-January/153156.html
> [3] https://www.spinics.net/lists/cgroups/msg20720.html
> [4] https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/scheduler
> [5] https://kubernetes.io/docs/tasks/manage-gpus/scheduling-gpus/
> [6] https://blog.openshift.com/gpu-accelerated-sql-queries-with-postgresql-pg-strom-in-openshift-3-10/
> [7] https://github.com/RadeonOpenCompute/k8s-device-plugin
> [8] https://github.com/kubernetes/kubernetes/issues/52757
>
> Kenny Ho (11):
> cgroup: Introduce cgroup for drm subsystem
> drm, cgroup: Bind drm and cgroup subsystem
> drm, cgroup: Initialize drmcg properties
> drm, cgroup: Add total GEM buffer allocation stats
> drm, cgroup: Add peak GEM buffer allocation stats
> drm, cgroup: Add GEM buffer allocation count stats
> drm, cgroup: Add total GEM buffer allocation limit
> drm, cgroup: Add peak GEM buffer allocation limit
> drm, cgroup: Add compute as gpu cgroup resource
> drm, cgroup: add update trigger after limit change
> drm/amdgpu: Integrate with DRM cgroup
>
> Documentation/admin-guide/cgroup-v2.rst | 138 ++-
> Documentation/cgroup-v1/drm.rst | 1 +
> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 4 +
> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 48 +
> drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 6 +-
> drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 7 +
> drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 3 +
> .../amd/amdkfd/kfd_process_queue_manager.c | 153 +++
> drivers/gpu/drm/drm_drv.c | 12 +
> drivers/gpu/drm/drm_gem.c | 16 +-
> include/drm/drm_cgroup.h | 81 ++
> include/drm/drm_device.h | 7 +
> include/drm/drm_drv.h | 19 +
> include/drm/drm_gem.h | 12 +-
> include/linux/cgroup_drm.h | 138 +++
> include/linux/cgroup_subsys.h | 4 +
> init/Kconfig | 5 +
> kernel/cgroup/Makefile | 1 +
> kernel/cgroup/drm.c | 913 ++++++++++++++++++
> 19 files changed, 1563 insertions(+), 5 deletions(-)
> create mode 100644 Documentation/cgroup-v1/drm.rst
> create mode 100644 include/drm/drm_cgroup.h
> create mode 100644 include/linux/cgroup_drm.h
> create mode 100644 kernel/cgroup/drm.c
>
> --
> 2.25.0
>