From: Daniel Vetter <daniel@ffwll.ch>
To: Alex Deucher <alexdeucher@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>, Kenny Ho <y2kenny@gmail.com>,
Song Liu <songliubraving@fb.com>,
Andrii Nakryiko <andriin@fb.com>,
DRI Development <dri-devel@lists.freedesktop.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Kenny Ho <Kenny.Ho@amd.com>,
"open list:CONTROL GROUP (CGROUP)" <cgroups@vger.kernel.org>,
Brian Welty <brian.welty@intel.com>,
John Fastabend <john.fastabend@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
amd-gfx list <amd-gfx@lists.freedesktop.org>,
Martin KaFai Lau <kafai@fb.com>,
Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Network Development <netdev@vger.kernel.org>,
KP Singh <kpsingh@chromium.org>, Yonghong Song <yhs@fb.com>,
bpf <bpf@vger.kernel.org>, Dave Airlie <airlied@gmail.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Alex Deucher <alexander.deucher@amd.com>
Subject: Re: [RFC] Add BPF_PROG_TYPE_CGROUP_IOCTL
Date: Fri, 7 May 2021 18:26:23 +0200 [thread overview]
Message-ID: <YJVqL4c6SJc8wdkK@phenom.ffwll.local> (raw)
In-Reply-To: <CADnq5_Pvtj1vb0bak_gUkv9J3+vfsMZxVKTKYeUvwQCajAWoVQ@mail.gmail.com>
On Fri, May 07, 2021 at 12:19:13PM -0400, Alex Deucher wrote:
> On Fri, May 7, 2021 at 12:13 PM Daniel Vetter <daniel@ffwll.ch> wrote:
> >
> > On Fri, May 07, 2021 at 11:33:46AM -0400, Kenny Ho wrote:
> > > On Fri, May 7, 2021 at 4:59 AM Daniel Vetter <daniel@ffwll.ch> wrote:
> > > >
> > > > Hm I missed that. I feel like time-sliced-of-a-whole gpu is the easier gpu
> > > > cgroups controler to get started, since it's much closer to other cgroups
> > > > that control bandwidth of some kind. Whether it's i/o bandwidth or compute
> > > > bandwidht is kinda a wash.
> > > sriov/time-sliced-of-a-whole gpu does not really need a cgroup
> > > interface since each slice appears as a stand alone device. This is
> > > already in production (not using cgroup) with users. The cgroup
> > > proposal has always been parallel to that in many sense: 1) spatial
> > > partitioning as an independent but equally valid use case as time
> > > sharing, 2) sub-device resource control as opposed to full device
> > > control motivated by the workload characterization paper. It was
> > > never about time vs space in terms of use cases but having new API for
> > > users to be able to do spatial subdevice partitioning.
> > >
> > > > CU mask feels a lot more like an isolation/guaranteed forward progress
> > > > kind of thing, and I suspect that's always going to be a lot more gpu hw
> > > > specific than anything we can reasonably put into a general cgroups
> > > > controller.
> > > The first half is correct but I disagree with the conclusion. The
> > > analogy I would use is multi-core CPU. The capability of individual
> > > CPU cores, core count and core arrangement may be hw specific but
> > > there are general interfaces to support selection of these cores. CU
> > > mask may be hw specific but spatial partitioning as an idea is not.
> > > Most gpu vendors have the concept of sub-device compute units (EU, SE,
> > > etc.); OpenCL has the concept of subdevice in the language. I don't
> > > see any obstacle for vendors to implement spatial partitioning just
> > > like many CPU vendors support the idea of multi-core.
> > >
> > > > Also for the time slice cgroups thing, can you pls give me pointers to
> > > > these old patches that had it, and how it's done? I very obviously missed
> > > > that part.
> > > I think you misunderstood what I wrote earlier. The original proposal
> > > was about spatial partitioning of subdevice resources not time sharing
> > > using cgroup (since time sharing is already supported elsewhere.)
> >
> > Well SRIOV time-sharing is for virtualization. cgroups is for
> > containerization, which is just virtualization but with less overhead and
> > more security bugs.
> >
> > More or less.
> >
> > So either I get things still wrong, or we'll get time-sharing for
> > virtualization, and partitioning of CU for containerization. That doesn't
> > make that much sense to me.
>
> You could still potentially do SR-IOV for containerization. You'd
> just pass one of the PCI VFs (virtual functions) to the container and
> you'd automatically get the time slice. I don't see why cgroups would
> be a factor there.
Standard interface to manage that time-slicing. I guess for SRIOV it's all
vendor sauce (intel as guilty as anyone else from what I can see), but for
cgroups that feels like it's falling a bit short of what we should aim
for.
But dunno, maybe I'm just dreaming too much :-)
-Daniel
> Alex
>
> >
> > Since time-sharing is the first thing that's done for virtualization I
> > think it's probably also the most reasonable to start with for containers.
> > -Daniel
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
> > _______________________________________________
> > amd-gfx mailing list
> > amd-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/amd-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
next prev parent reply other threads:[~2021-05-07 16:26 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 15:23 [RFC] Add BPF_PROG_TYPE_CGROUP_IOCTL Kenny Ho
2020-11-02 19:23 ` Kenny Ho
2020-11-03 5:32 ` Alexei Starovoitov
2020-11-03 5:39 ` Kenny Ho
2020-11-03 5:42 ` Alexei Starovoitov
2020-11-03 19:19 ` Kenny Ho
2020-11-03 21:04 ` Alexei Starovoitov
2020-11-03 22:57 ` Kenny Ho
2020-11-03 23:28 ` Alexei Starovoitov
2021-02-01 14:49 ` Daniel Vetter
2021-02-01 16:51 ` Kenny Ho
2021-02-03 11:09 ` Daniel Vetter
2021-02-03 19:01 ` Kenny Ho
2021-02-05 13:49 ` Daniel Vetter
2021-05-07 2:06 ` Kenny Ho
2021-05-07 8:59 ` Daniel Vetter
2021-05-07 15:33 ` Kenny Ho
2021-05-07 16:13 ` Daniel Vetter
2021-05-07 16:19 ` Alex Deucher
2021-05-07 16:26 ` Daniel Vetter [this message]
2021-05-07 16:31 ` Alex Deucher
2021-05-07 16:50 ` Alex Deucher
2021-05-07 16:54 ` Daniel Vetter
2021-05-07 17:04 ` Kenny Ho
2021-05-07 19:33 ` Tejun Heo
2021-05-07 19:55 ` Alex Deucher
2021-05-07 20:59 ` Tejun Heo
2021-05-07 22:30 ` Alex Deucher
2021-05-07 23:45 ` Tejun Heo
2021-05-11 15:48 ` Alex Deucher
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