Really interesting benchmark, thank you. > On 8 Nov 2023, at 23:04, Martin Desruisseaux > <[email protected]> wrote: > > Hello all > > Apache SIS 1.4 contains a Cloud Optimized GeoTIFF reader, and a GeoTIFF > writer is currently available in 1.5-SNAPSHOT (not yet fully completed). > Those reader/writer are in pure Java (ignoring native code provided by the > JDK itself). There is a widespread belief that a Java code would surely be > slower than C/C++ code. To verify, we conducted a superficial benchmark. It > is very superficial in that we tested only one image with one compression > method, no sub-region, no subsampling, no parallelization, no reprojection, > etc. But the results nevertheless question the above-cited belief. In that > benchmark, Apache SIS and GDAL performances were equivalent. The numbers > actually report Apache SIS as very slightly faster than GDAL, but we cannot > conclude much because of all above-cited limitations, because there is a > possibility of biais in time measurements (we tried to compensate it), > because the differences are close to margin errors, and because Apache SIS > spent 95% of its time in the native code of the `java.util.zip` package. > Assuming that GDAL also uses the `zlib` library (we did not tested with > `libdeflate`), 95% of this benchmark is actually measuring the same code. > However for the remaining 5%, it suggests that the interfacing between Java > and the native code in `java.nio` and `java.util.zip` packages can be as > efficient as the interfacing between a C/C++ application and native libraries. > > More details are there: > https://www.geomatys.com/2023/10/05/geotiff-reader-writer-performance-comparison/ > > Martin > >
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