> Certain signatures for foreign function calls (e.g. HVA return by value) > require allocation of an intermediate buffer to adapt the FFM's to the native > stub's calling convention. In the current implementation, this buffer is > malloced and freed on every FFM invocation, a non-negligible overhead. > > Sample stack trace: > > java.lang.Thread.State: RUNNABLE > at jdk.internal.misc.Unsafe.allocateMemory0(java.base@25-ea/Native > Method) > ... > at > jdk.internal.foreign.abi.SharedUtils.newBoundedArena(java.base@25-ea/SharedUtils.java:386) > at > jdk.internal.foreign.abi.DowncallStub/0x000001f001084c00.invoke(java.base@25-ea/Unknown > Source) > ... > at > java.lang.invoke.Invokers$Holder.invokeExact_MT(java.base@25-ea/Invokers$Holder) > > > To alleviate this, this PR implements a per carrier-thread stacked allocator. > > Performance (MBA M3): > > > Before: > Benchmark Mode Cnt Score Error Units > CallOverheadByValue.byPtr avgt 10 3.333 ? 0.152 ns/op > CallOverheadByValue.byValue avgt 10 33.892 ? 0.034 ns/op > > After: > Benchmark Mode Cnt Score Error Units > CallOverheadByValue.byPtr avgt 30 3.311 ? 0.034 ns/op > CallOverheadByValue.byValue avgt 30 6.143 ? 0.053 ns/op > > > `-prof gc` also shows that the new call path is fully scalar-replaced vs 160 > byte/call before.
Matthias Ernst has updated the pull request incrementally with one additional commit since the last revision: Apply suggestions from code review Co-authored-by: Jorn Vernee <jornver...@users.noreply.github.com> ------------- Changes: - all: https://git.openjdk.org/jdk/pull/23142/files - new: https://git.openjdk.org/jdk/pull/23142/files/13dfec94..f09a29de Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=23142&range=14 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23142&range=13-14 Stats: 4 lines in 2 files changed: 1 ins; 1 del; 2 mod Patch: https://git.openjdk.org/jdk/pull/23142.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/23142/head:pull/23142 PR: https://git.openjdk.org/jdk/pull/23142
