RFR: 8181147: JNI_GetStringPlatformChars should have a fast path for UTF-8
claes.redestad at oracle.com
Fri May 26 17:58:15 UTC 2017
various JNI methods in the JDK converts from java Strings to native
encoding using JNI_GetStringPlatformChars, which has long standing
optimizations for dealing with various default charsets.
However, UTF-8 is missing, which is a shame since we have optimized
utilities for converting from a String to UTF-8-encoded char* (since
this is the native encoding used by HotSpot internally).
Allocation rate can drop significantly in microbenchmarks, e.g., -60%
in a trivial micro doing new File(path).isHidden() (along with a 30%
throughput win), while the rate of native allocation with is net neutral.
(I think the code for FAST_646_US could be removed, since Solaris 8
support was dropped in JDK 8, but that's a separate RFE...)
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