On Mon, 8 Apr 2024 19:11:19 GMT, Scott Gibbons <sgibb...@openjdk.org> wrote:
>> This code makes an intrinsic stub for `Unsafe::setMemory` for x86_64. See >> [this PR](https://github.com/openjdk/jdk/pull/16760) for discussion around >> this change. >> >> Overall, making this an intrinsic improves overall performance of >> `Unsafe::setMemory` by up to 4x for all buffer sizes. >> >> Tested with tier-1 (and full CI). I've added a table of the before and >> after numbers for the JMH I ran (`MemorySegmentZeroUnsafe`). >> >> [setMemoryBM.txt](https://github.com/openjdk/jdk/files/14808974/setMemoryBM.txt) > > Scott Gibbons has updated the pull request incrementally with one additional > commit since the last revision: > > Add movq to locate_operand src/hotspot/cpu/x86/stubGenerator_x86_64_arraycopy.cpp line 2497: > 2495: // > 2496: address StubGenerator::generate_unsafe_setmemory(const char *name, > 2497: address > byte_fill_entry) { Need to add UnsafeSetMemoryMark on similar lines as UnsafeCopyMemoryMark to handle page error. src/hotspot/cpu/x86/stubGenerator_x86_64_arraycopy.cpp line 2522: > 2520: #define rScratch3 r8 > 2521: #undef rScratch4 > 2522: #define rScratch4 r11 We could do this setup using const Register declaration instead of using #undef/#define pair. src/hotspot/share/opto/library_call.cpp line 4950: > 4948: > 4949: bool LibraryCallKit::inline_unsafe_setMemory() { > 4950: if (callee()->is_static()) return false; // caller must have the > capability! Also need to return false if StubRoutines::unsafe_setmemory() == nullptr. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/18555#discussion_r1560201153 PR Review Comment: https://git.openjdk.org/jdk/pull/18555#discussion_r1560202218 PR Review Comment: https://git.openjdk.org/jdk/pull/18555#discussion_r1560194011
