Tune thomaswue submission. #1
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mmap the entire file, use Unsafe directly instead of ByteBuffer, avoid byte[] copies. These tricks give a ~30% speedup, over an already fast implementation.
thomaswue
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Jan 18, 2024
…m 16th based on local testing; no Unsafe; no bitwise tricks yet (gunnarmorling#465) * Squashing a bunch of commits together. Commit#2; Uplift of 7% using native byteorder from ByteBuffer. Commit#1: Minor changes to formatting. * Commit gunnarmorling#4: Parallelize munmap() and reduce completion time further by 10%. As the jvm exits with exit(0) syscall, the kernel reclaims the memory mappings via munmap() call. Prior to this change. all the unmap() calls were happening right at the end as the JVM exited. This led to serial execution of about 350ms out of 2500 ms right at the end after each shard completed its work. We can parallelize it by exposing the Cleaner from MappedByteBuffer and then ensure that it is truly parallel execution of munmap() by using a non-blocking lock (SeqLock). The optimal strategy for when each thread must call unmap() is an interesting math problem with an exact solution and this code roughly reflects it. Commit gunnarmorling#3: Tried out reading long at a time from bytebuffer and checking for presence of ';'.. it was slower compared to just reading int(). Removed the code for reading longs; just retaining the hasSemicolonByte(..) check code Commit gunnarmorling#2: Introduce processLineSlow() and processRangeSlow() for the tial part. Commit #1: Create a separate tail piece of work for the last few lines to be processed separately from the main loop. This allows the main loop to read past its allocated range (by a 'long' if we reserve atleast 8 bytes for the tail piece of work.)
thomaswue
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Jan 28, 2024
* Latest snapshot (#1) preparing initial version * Improved performance to 20seconds (-9seconds from the previous version) (gunnarmorling#2) improved performance a bit * Improved performance to 14 seconds (-6 seconds) (gunnarmorling#3) improved performance to 14 seconds * sync branches (gunnarmorling#4) * initial commit * some refactoring of methods * some fixes for partitioning * some fixes for partitioning * fixed hacky getcode for utf8 bytes * simplified getcode for partitioning * temp solution with syncing * temp solution with syncing * new stream processing * new stream processing * some improvements * cleaned stuff * run configuration * round buffer for the stream to pages * not using compute since it's slower than straightforward get/put. using own byte array equals. * using parallel gc * avoid copying bytes when creating a station object * formatting * Copy less arrays. Improved performance to 12.7 seconds (-2 seconds) (gunnarmorling#5) * initial commit * some refactoring of methods * some fixes for partitioning * some fixes for partitioning * fixed hacky getcode for utf8 bytes * simplified getcode for partitioning * temp solution with syncing * temp solution with syncing * new stream processing * new stream processing * some improvements * cleaned stuff * run configuration * round buffer for the stream to pages * not using compute since it's slower than straightforward get/put. using own byte array equals. * using parallel gc * avoid copying bytes when creating a station object * formatting * some tuning to increase performance * some tuning to increase performance * avoid copying data; fast hashCode with slightly more collisions * avoid copying data; fast hashCode with slightly more collisions * cleanup (gunnarmorling#6) * tidy up
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mmap the entire file, use Unsafe directly instead of ByteBuffer, avoid byte[] copies. These tricks give a ~30% speedup, over an already fast implementation.