[Bug 100899] New: Enable UMD to control GPGPU EUs slice number in static/dynamic way

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=100899

            Bug ID: 100899
           Summary: Enable UMD to control GPGPU EUs slice number in
                    static/dynamic way
           Product: DRI
           Version: unspecified
          Hardware: Other
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: medium
         Component: DRM/Intel
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: dmitry.v.rogozhkin at intel.com
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
                CC: intel-gfx-bugs at lists.freedesktop.org

Media workloads performance may suffer because of the cost associated with
managing of GPGPU EUs slices which are not required for the workloads (media
workloads may use no more than certain number of EUs at the same time due to
wave front limitation). Usually the rule is: lower stream resolution, lower
number of EUs slices is needed. According to experiments, performance may be
5-20% lower from the optimal operating point. This under performance is one of
the key factors why in certain use cases SKL is slower than BDW assuming all
other system settings except EU aligned.

Here is a link to the feature request to provide an API on the UMD level to
permit user to control number of slices selections to potentially benefit the
performance: https://github.com/01org/intel-vaapi-driver/issues/152

Here are links to the RFC i915 drm-tip patches to enable static slice shutdown
for BDW and SKL:
* https://patchwork.kernel.org/patch/9670509/ [RFC,2/2] drm/i915/bdw: permit
make_rpcs execution on BDW to enable slice shutdown
* https://patchwork.kernel.org/patch/9670507/ [RFC,1/2] drm/i915/skl: add slice
shutdown debugfs interface

These patches can be used to demonstrate influence of EUs slice numbers on the
media workloads. Refer to
https://github.com/01org/intel-vaapi-driver/issues/152 for the reproducing
details.

-- 
You are receiving this mail because:
You are the assignee for the bug.
You are the QA Contact for the bug.
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20170502/370e9848/attachment.html>