I have confirmed hit a different code path. It goes through generic 2D
s/w loops in this case.
ie we don't use GDIBlitLoops at all. The code in
sun/java2d/pipe/DrawImage.java ends up in
scaleSurfaceData which uses the loops in ScaledBlit.c.
It is a bit surprising to me since I'd expect us to be able to blit
directly at device resolution.
Could we also be taking a performance hit here ? The D3D case doesn't
not go through this loop.
However all that is outside the scope of this fix ... I think setting
uiScale=1 in the test is all that needs to be done.
-phil.
On 6/11/2020 7:51 AM, Philip Race wrote:
Or, maybe we hit a different code path. I'll check that.
uiScale=1 is the way to ensure we hit this code path.
-phil.
On 6/11/20, 7:44 AM, Philip Race wrote:
Can I get clarification here.
> I do, and had to run with "-Dsun.java2d.uiScale=1" in order to see
the failure with LargeWindowPaintTest.
So you both mean a JDK 15 promoted build without this fix and without
this property passes because you have
a hidpi setup. And to see the failure without the fix you needed the
above property.
If so we could just be looking at a similar anomaly as I saw with
printing which uses a very large
image - it reported failure but actually worked !
Also - for both of you - with the fix and without forcing uiScale=1
does the test pass ?
-phil.
On 6/11/20, 7:10 AM, Jayathirth D v wrote:
Yes my machine was at 150% scaling.
If I force uiScale = 1, I see that:
LargeWindowPaintTest fails without patch and passes with patch.
AlphaPrintTest shows instructions without patch also.
@Phil : I think its better if we test at uiScale=1(larger memory
footprint). Please clarify.
Thanks,
Jay
On 11-Jun-2020, at 5:53 PM, Kevin Rushforth
<kevin.rushfo...@oracle.com <mailto:kevin.rushfo...@oracle.com>> wrote:
Do you have a Hi-DPI machine? I do, and had to run with
"-Dsun.java2d.uiScale=1" in order to see the failure with
LargeWindowPaintTest.
For AlphaPrintTest, the test deliberately ensures that you print
before saying whether it passes or not. FWIW, I verified that the
printing test on my system was hitting the fallback code with the
patch, but it seemed to print correctly even without the patch.
-- Kevin
On 6/11/2020 1:58 AM, Jayathirth D v wrote:
Typo : I tried tested -> I tried testing
On 11-Jun-2020, at 2:27 PM, Jayathirth D v
<jayathirth....@oracle.com <mailto:jayathirth....@oracle.com>> wrote:
Hi Phil,
I tried tested the fix in my Windows 10 machine with Intel
integrated UHD Graphics 620.
LargeWindowPaintTest.java passes with/without fix in my machine.
AlphaPrintTest.java without fix just opens up blank frame without
any instructions and with fix it shows instructions for the test.
Is this expected behaviour?
AlphaPrintTest.java with fix when it shows instructions if I
click on Pass(Since I don’t have printer right now) it doesn’t
pass/close the window. Only after I click on Print button and
then close print dialog it allows me to click on Pass button.
Also how does these tests behave in our internal CI machines?
Thanks,
Jay
On 11-Jun-2020, at 2:18 AM, Philip Race <philip.r...@oracle.com
<mailto:philip.r...@oracle.com>> wrote:
Bug: https://bugs.openjdk.java.net/browse/JDK-8240654
Webrev: http://cr.openjdk.java.net/~prr/8240654/index.html
This is for JDK 15 so review ASAP please since RDP 1 and the
test cycle are looming.
This is not a fix for a JDK bug. It is a bunch of workarounds
for a Microsoft Windows bug affecting
GDI in the context of ZGC (http://openjdk.java.net/jeps/333).
Some extra details about the Windows bug at the end, but first
the technical details of the fix.
With ZGC's memory allocation requirement of reserving memory in
2Mb chunks some Windows GDI
functions, mostly involving some bitmaps APIs may return a
failure code (ie fail!)
This typically occurs when Java heap memory is used for a Java
image and then in a JNI
call we use GetPrimitiveArrayCritical so that Java heap
allocated memory is passed to a GDI
function AND the Java heap memory spans one of the 2Mb boundaries.
This is very easy to trigger in almost any Java UI app if the
window is of a large enough (ie typical) size.
NB: if you have an Nvidia or ATI card, then you won't see it,
because the D3D pipeline doesn't
call the affected method but if you have an Intel chip as do 90%
(?) of laptops you will see it.
There are also several other places we found that are affected.
Printing is the other one
somewhat easy to trigger. The others : custom cursors and tray
icons are less common.
The painful thing here is that there is no definitive list (a
list of the known ones is below) of
affected Windows GDI APIs and we are just hunting around our
code trying to see where it
might be side-swiped by this bug.
The basic approach in these workarounds is that for cases where
performance does not matter we now copy
and for cases where performance does matter or larger amounts of
memory is involved we check if
the return value of the GDI function indicates failure and then
re-try with a copy of the heap memory.
Unless GDI was randomly failing already (unlikely) this should
be a no-risk solution in the high profile cases.
We have done performance measurements on the important screen
case and the failures
happen fast so the penalty is then in the re-try which is only
if ZGC is enabled.
Always copying the memory is slower (and memcpy is the slow
operation) than an alternative approach
that "knows" about the memory allocation of ZGC but this
coupling and the complexity seem like they aren't
worth it since I haven't seen any visible performance
consequence. That can be revisited
some day if need be, but for now we have correctness which is
the key as well as sufficient performance.
I've created an automated test for the most important on-screen
case.
Also a manual printing test case which invokes ZGC is provided
since there we also only
conditionally copy. In the other cases we now always copy so
existing test cases should over those.
There is some clean up in this fix - one completely unused
(provably so because it was #if'd out)
JNI method in awt_PrintJob.cpp is removed since it had code that
looked like it needed a workaround,
which would be somewhat of a waste of effort.
the doPrintBand code and its callee bitsToDevice has code I
think we can remove too since
I don't see how it ever gets executed (the top down case for
browserPrint == true) but
I think I'll save that for a P4 follow-on since it does nothing
that would be affected by this
Windows bug.
One oddity is the in the printing case I observed that some
times the rendering is performed
even if an error code is returned. I don't know why, but in code
we can't tell that it was actually
rendered and in any case there is no harm in repeating the call
with copied memory.
We are right before the JDK15 stabilisation fork and this fix
needs to go there and will
but the webrev is against jdk/client simply because jdk15 does
not exist yet !
Please test and review ASAP.
About the bug:
Microsoft has acknowleged the bug and will publish a knowledge
base article about it
but a fix may show up only in a future version of Windows. Not,
it seems, any time soon.
Below is a list of potentially affected GDI APIs. Per microsoft
whether it actually manifests in
any specific case depends on "branching"
https://docs.microsoft.com/en-us/previous-versions/windows/desktop/wcs/checkbitmapbits
https://docs.microsoft.com/en-us/previous-versions/windows/desktop/wcs/createcolortransform
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-setdibitstodevice
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-stretchdibits
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-getbitmapbits
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createdibitmap
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createdibsection
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-polydraw
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-drawescape
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createbitmap
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-setbitmapbits
https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-getdibits
-phil.
