drm/i915/gvt: Manage shadow pages with radix tree

Browse source

We don't know how many page tables will be shadowed. It varies
considerably corresponding to guest load. Radix tree is a better
choice for us. Since Page Frame Number is used as key so most of
the bits are common.

Here is some performance data (duration in us) of looking up a
element:
Before: (aka. ppgtt_find_shadow_page)
 0.308 0.292 0.246 0.432 0.143 ... 0.311 0.225 0.382 0.199 0.325
After: (aka. intel_vgpu_find_spt_by_mfn)
 0.106 0.106 0.107 0.106 0.105 0.107 ... 0.107 0.109 0.105 0.108

This time I didn't get the early data of hash table. The data is
measured when desktop is shown.

As last change, the overall benchmark almost is not changed, but
we get better scalability.

Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

...

This commit is contained in:

Changbin Du 2018-01-30 19:19:54 +08:00 • committed by Zhenyu Wang

parent e502a2af4c

commit b6c126a393

2 changed files with 27 additions and 27 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

50

drivers/gpu/drm/i915/gvt/gtt.c

View file

4

drivers/gpu/drm/i915/gvt/gtt.h

View file