[OpenJDK 2D-Dev]  request for review: 8087201: OGL: rendering of lcd text is slow
andrew.brygin at oracle.com
Fri Jul 3 14:24:25 UTC 2015
Roughly speaking, the rendering of lcd text with d3d pipeline is 10-20 times
faster that with ogl:
On windows, the suggested fix gives mixed results. It does not affect
the case of
rendering to the screen, because in this case destination SD does not
have a texture.
The effect on rendering to a volatile image depends on hardware/drivers
* Intel HD graphics
There is no NV_texture_barrier extension, so effective parts of the
change here is
cache separation and the increase of cache celll size. It gives
about x4 speedup
for big glyphs. All other cases are not affected.
The NV_texture_barrier is available here, and the fix makes the
rendering 2-3 times
here the fix causes significant performance degradation. A reason of
is not clear to me yet. Probably it is due to significant overhead
So, the fix does not give significant advantage on windows (ogl is still far
slower than d3d in lcd text rendering), and even makes thing worse in some
cases. On osx (at least on 10.9 - 10.10) the fix helps to increase the
speed up to 10 times.
Probably we can consider to use this approach for osx only (see
lines 1007 - 1029):
What do you think?
On 6/25/2015 8:08 PM, Phil Race wrote:
> On 06/25/2015 03:33 AM, Andrew Brygin wrote:
>>> Given that it is a unified driver it sounds like we may be want
>>> to disable this code path when on windows at least for NV but I
>>> guess we
>>> may also want to validate that on some other cards - from Nvidia - to
>>> see if it is a driver or h/w limitation.
>> Probably, we should to run the text benchmarks on relatively big set
>> of windows
>> machines, and if we see that good performance of glCopyTexSubImage()
>> is sooner
>> a rule than an exception, then we can just disable the new code path
>> on windows.
>> Wat do you think?
> Also it occurs to me to wonder why we have not had the same
> performance complaints
> when using D3D on Windows .. different APIs but they have the same
> It would be interesting to know if objective performance tests on the
> same hardware
> show that Windows users are more forgiving or it really is not a
> problem there ...
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