On Thu, 19 Jun 2025 08:19:55 GMT, Per Minborg <pminb...@openjdk.org> wrote:
>> This PR aims to Panamize the Java Kqueue implementation, This is based on >> the work that was previously shared in >> https://github.com/openjdk/jdk/pull/22307 , The main change since then is >> that this branch takes advantage of the changes made in >> https://github.com/openjdk/jdk/pull/25043 to allow for better performance >> during errno handling. >> >> These changes feature a lot of Jextract generated files, though alterations >> have been made in relation to Errno handling and performance improvements. >> >> I will update this description soon to include performance metrics on a few >> microbenchmarks, though currently it's roughly 2% to 3% slower with the >> changes, which is somewhat expected, though there are still a few ideas of >> possible performance improvements that could be tried. Any suggestions or >> comments in that area are more than welcome however. > > src/java.base/macosx/classes/jdk/internal/ffi/generated/BindingUtils.java > line 45: > >> 43: public static final AddressLayout C_POINTER = ValueLayout.ADDRESS >> 44: >> .withTargetLayout(MemoryLayout.sequenceLayout(Long.MAX_VALUE, JAVA_BYTE)); >> 45: public static final ValueLayout.OfLong C_LONG = >> ValueLayout.JAVA_LONG; > > This is `int` on Windows. So, we could perhaps use > `Linker.nativeLinker().canonicalLayouts().get("long")` here? "size_t" and > "wchar_t" are other canonical layouts that may differ across platforms. I think this is a good idea and would allow us to make BindingUtils shared, Though I wonder if it's best to move BindingUtils to be shared, or if its worth merging it into FFMUtils. I'd favour the second option > src/java.base/macosx/classes/jdk/internal/ffi/generated/kqueue/kqueue_h.java > line 263: > >> 261: var adapted$ = kevent64.ADAPTED; >> 262: try { >> 263: if (FFMUtils.TRACE_DOWNCALLS) { > > I wonder what the price of this `if` branch might be (if any)? The javac > compiler probably sees the > > `public static final boolean TRACE_DOWNCALLS = false;` as constant foldable > and can eliminate the code at compile time. I think that's a good question, I can do some testing with it removed to see if theres any gain to be had ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/25546#discussion_r2159147090 PR Review Comment: https://git.openjdk.org/jdk/pull/25546#discussion_r2140347487
