The demo I want to work on is 3d reconstruction from the camera. there’s a couple of papers that do that for simple images, but it’s pretty hard for real world ones. https://paperswithcode.com/paper/soft-rasterizer-a-differentiable-renderer-for
🤔
Just need to find the native-image xml files I made last time a long time ago….
The same as JNI, about 30 ns on average, for example: https://github.com/oracle/graal/issues/885#issuecomment-456299353
so i was doing some benchmarking for my use case and I am seeing about 25 microseconds on the average call.
the timing that I am doing is c++ calling a java object method that i passed to the c++ section. the java object is extending from a pure vitrual c++ class. I originally thought it might have been all of the arguments that was being passed through on the method signature, but then i changed it to just call an empty method with no arguments and I was still seeing about the same timestamps.
the timing that I am doing is c++ calling a java object method that i passed to the c++ section. the java object is extending from a pure vitrual c++ class. I originally thought it might have been all of the arguments that was being passed through on the method signature, but then i changed it to just call an empty method with no arguments and I was still seeing about the same timestamps.
I understand that this is a different use case from what you sent, but it seems like it shouldn't be orders of magnitude slower
I made a very simple program that gives an object created in java from a virtual c++ class to a c++ thread and just have it call a method on the virtual class. the method does nothing and takes no arguments, however it is taking around 14 microseconds to make that call. better then the 25 i mentioned earlier, but still pretty slow. It is also GCing like crazy when i put on gc logging.
I ran a test that timed empty method calls from java to cpp and i got the results that you posted above... about 30 nanoseconds per call.
so it seems like that doing callbacks is very expensive. is that something that is expected?
hmm, that is exactly what I am seeing then. I don't really have control of the thread that is being spawned, just the results of the thread. so then I think the best route to go without having control of the c++ thread then would be to store the results from the c++ initialized thread in a thread safe container in c++, then poll that container from java?
If the thread is never deallocated, it's possible to tell that to JavaCPP and it will initialize it only once and never detach it by setting the
NO_JNI_DETACH_THREAD, for example, this way: https://github.com/bytedeco/javacpp/issues/143#issuecomment-262138799
Actually, according to various sources, the hack that @tmm1 created for pthreads on Android should also work fine with OpenJDK, so I've enabled that in the commit bytedeco/javacpp@89d6069. As long as you're not on Windows, that should do what you need automatically.
right, i was trying that. first with just a void method with the struct passed through to the c++ layer but the struct didnt seem to update, so i am returning a struct as well in the method. I haven't looked to deep into the documentation, but there isn't a struct equivalent that I need to make in java, right? Its just a pointer object
i have a crash
Stack: [0x0000700005eeb000,0x0000700005feb000], sp=0x0000700005fe5e80, free space=1003k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
C [libsystem_platform.dylib+0x929] _platform_memmove$VARIANT$Haswell+0x29
C [libopencv_core.3.2.dylib+0x614ee] _ZNK2cv3Mat6copyToERKNS_12_OutputArrayE+0xc2e
C [libopencv_core.3.2.dylib+0x147077] _ZNK2cv11_InputArray6copyToERKNS_12_OutputArrayE+0x387
C [libopencv_imgproc.3.2.dylib+0x276b7] _ZN2cv8cvtColorERKNS_11_InputArrayERKNS_12_OutputArrayEii+0x257
C [libjniopencv_imgproc.dylib+0x7be79] Java_org_bytedeco_javacpp_opencv_1imgproc_cvtColor__Lorg_bytedeco_javacpp_opencv_1core_00024Mat_2Lorg_bytedeco_javacpp_opencv_1core_00024Mat_2I+0xf9
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
C [libsystem_platform.dylib+0x929] _platform_memmove$VARIANT$Haswell+0x29
C [libopencv_core.3.2.dylib+0x614ee] _ZNK2cv3Mat6copyToERKNS_12_OutputArrayE+0xc2e
C [libopencv_core.3.2.dylib+0x147077] _ZNK2cv11_InputArray6copyToERKNS_12_OutputArrayE+0x387
C [libopencv_imgproc.3.2.dylib+0x276b7] _ZN2cv8cvtColorERKNS_11_InputArrayERKNS_12_OutputArrayEii+0x257
C [libjniopencv_imgproc.dylib+0x7be79] Java_org_bytedeco_javacpp_opencv_1imgproc_cvtColor__Lorg_bytedeco_javacpp_opencv_1core_00024Mat_2Lorg_bytedeco_javacpp_opencv_1core_00024Mat_2I+0xf9
mac os x catalina
<dependency>
<groupId>org.bytedeco.javacpp-presets</groupId>
<artifactId>opencv-platform</artifactId>
<version>${javacv.presets.version}</version>
</dependency>
<dependency>
<groupId>org.bytedeco</groupId>
<artifactId>javacpp</artifactId>
<version>${javacv.version}</version>
</dependency>
<dependency>
<groupId>org.bytedeco</groupId>
<artifactId>javacv</artifactId>
<version>${javacv.version}</version>
</dependency> <javacv.version>1.3.3</javacv.version>
<javacv.presets.version>3.2.0-1.3</javacv.presets.version>Mat matrix = new OpenCVFrameConverter.ToMat().convert(new Java2DFrameConverter().convert(bufferedImage));
Mat grayMatrix = new Mat(matrix.size(), CV_8UC1);
if (matrix.channels() == 4) {
cvtColor(matrix, matrix, CV_BGRA2BGR); <<< crashing here with SIGSEGV on 6k/9k pixel image
}
A fatal error has been detected by the Java Runtime Environment:
#
SIGSEGV (0xb) at pc=0x00007fff6f52d929, pid=10594, tid=0x000000000001b923
#
JRE version: Java(TM) SE Runtime Environment (8.0_261-b12) (build 1.8.0_261-b12)
Java VM: Java HotSpot(TM) 64-Bit Server VM (25.261-b12 mixed mode bsd-amd64 compressed oops)
Problematic frame:
C [libsystem_platform.dylib+0x929] _platform_memmove$VARIANT$Haswell+0x29
no luck though so far i think whatever im doing isnt enough because the images are filled with noise
@supergrecko Would you be able to help this guy? https://stackoverflow.com/questions/65634369/llvm-ir-with-java-api