On 10/02/2014 06:55 PM, Vladimir Ivanov wrote:
Small update:
http://cr.openjdk.java.net/~vlivanov/8058892/webrev.01/
Need to reorder initialization sequence in MHI.Lazy. Initialized
FILL_ARRAYS and ARRAYS are required for later MH lookups.
Additional testing:
* jck (api/java_lang/invoke)
* jdk/java/lang/invoke, jdk/java/util/streams w/ "-ea -esa" and
COMPILE_THRESHOLD={0,30}
Best regards,
Vladimir Ivanov
Hi Vladimir,
I have a comment that does not directly pertain to the code changes (the
initialization of arrays) but to the sub-optimal implementation of
"fillArray" methods I noticed by the way. While it is nice to use
varargs "makeArray" helper method with "array" methods to construct the
array, the same strategy used with "fillWithArguments" in "fillArray"
methods makes a redundant array that is then copied to target array and
discarded. The redundant copying has a price. Here's a benchmark
(Aleksey, please bear with me):
@State(Scope.Benchmark)
public class FillArrayTest {
private Object
a0 = new Object(),
a1 = new Object(),
a2 = new Object(),
a3 = new Object(),
a4 = new Object(),
a5 = new Object(),
a6 = new Object(),
a7 = new Object();
private static void fillWithArguments(Object[] a, int pos,
Object... args) {
System.arraycopy(args, 0, a, pos, args.length);
}
private static Object[] fillArray(
Integer pos, Object[] a,
Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7
) {
fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7);
return a;
}
private static Object[] fillArrayAlt(
Integer pos, Object[] a,
Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7
) {
int i = pos;
a[i++] = a0;
a[i++] = a1;
a[i++] = a2;
a[i++] = a3;
a[i++] = a4;
a[i++] = a5;
a[i++] = a6;
a[i++] = a7;
return a;
}
@Benchmark
public Object[] fillArray() {
return fillArray(0, new Object[8], a0, a1, a2, a3, a4, a5, a6, a7);
}
@Benchmark
public Object[] fillArrayAlt() {
return fillArrayAlt(0, new Object[8], a0, a1, a2, a3, a4, a5,
a6, a7);
}
}
The results on my i7 with JMH arguments "-i 8 -wi 5 -f 1 -gc true":
Benchmark Mode Samples Score Score
error Units
j.t.FillArrayTest.fillArray thrpt 8 48601447.674
5414853.634 ops/s
j.t.FillArrayTest.fillArrayAlt thrpt 8 90044973.732
8713725.735 ops/s
So fillArrayAlt is nearly twice as fast...
Regards, Peter
On 10/2/14, 7:52 PM, Vladimir Ivanov wrote:
http://cr.openjdk.java.net/~vlivanov/8058892/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8058892
Core j.l.i classes are preloaded during VM startup in order to avoid
possible deadlock when accessing JSR292-related functionality from
multiple threads. After LF sharing-related changes, FILL_ARRAYS and
ARRAYS are initialized too early. It affects startup time & footprint of
applications that don't use JSR292.
The fix is to move these fields into MHI.Lazy class, thus delaying their
initialization to the first usage of JSR292 API.
Testing: failing test, manual (measured HelloWorld app startup time;
compared -XX:+PrintCompilation logs)
Best regards,
Vladimir Ivanov
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