On Fri, May 7, 2021 at 3:33 PM Tejun Heo [off-list ref] wrote:

Hello,

On Fri, May 07, 2021 at 06:54:13PM +0200, Daniel Vetter wrote:

quoted

All I meant is that for the container/cgroups world starting out with
time-sharing feels like the best fit, least because your SRIOV designers
also seem to think that's the best first cut for cloud-y computing.
Whether it's virtualized or containerized is a distinction that's getting
ever more blurry, with virtualization become a lot more dynamic and
container runtimes als possibly using hw virtualization underneath.

FWIW, I'm completely on the same boat. There are two fundamental issues with
hardware-mask based control - control granularity and work conservation.
Combined, they make it a significantly more difficult interface to use which
requires hardware-specific tuning rather than simply being able to say "I
wanna prioritize this job twice over that one".

My knoweldge of gpus is really limited but my understanding is also that the
gpu cores and threads aren't as homogeneous as the CPU counterparts across
the vendors, product generations and possibly even within a single chip,
which makes the problem even worse.

Given that GPUs are time-shareable to begin with, the most universal
solution seems pretty clear.

The problem is temporal partitioning on GPUs is much harder to enforce
unless you have a special case like SR-IOV.  Spatial partitioning, on
AMD GPUs at least, is widely available and easily enforced.  What is
the point of implementing temporal style cgroups if no one can enforce
it effectively?

Alex

Thanks.

--
tejun