Hello Tagir!
On 4/30/19 8:57 AM, Tagir Valeev wrote:
Hello!
New webrev looks good. Probably it worth adding a testcase for
overflow (assert that OOME is thrown)? I guess, something like
"1".repeat(65536).replace("1", "1".repeat(65536)) would produce OOME
quite fast and without allocating much memory.
Good point! Will do.
With kind regards,
Ivan
With best regards,
Tagir Valeev.
On Tue, Apr 30, 2019 at 11:43 AM Ivan Gerasimov
<ivan.gerasi...@oracle.com> wrote:
Hello everyone!
Please help review the second version of the enhancement.
A separate branch was added to handle UTF16 in the searched string and/or in
the target and replacement.
Switching to Math.xxxExact() suggested by Tagir gave ~4% of throughput on
affected test cases.
Also, allocating uninitialized array added ~7% for Latin1 strings.
I used StringConcatHelper.newArray() to avoid bringing Unsafe into StringLatin1.
In the StringLatin1.replace(), the newly allocated array is guaranteed to be
filled up, and the filling code should never throw, so I believe using
uninitialized arrays here is justified.
Here's the updated webrev:
http://cr.openjdk.java.net/~igerasim/8222955/01/webrev/
Below please find the benchmark numbers (with an additional column, showing the
improvement.)
Surprisingly, in one test case a slowdown was observed: Only for Latin1
string, with 1-char target, when the target string was *not* found.
If I understood it correctly, this is because prior the fix the intrinsified
StringLatin1.indexOf(byte[], byte[]) was called on the first place, so there
were effectively a fast path for exactly this pattern.
I'm not quite sure what to do about it.
Maybe this is fine as it is, since the *average* improvement across different
test cases is still good?
- prior fix:
Benchmark Mode Cnt Score Error Units
StringReplace.replace0x1_1_Latin1 avgt 15 7.116 ± 0.060 ns/op
StringReplace.replace0x1_1_UTF16 avgt 15 84.255 ± 3.381 ns/op
StringReplace.replace1x1_0_Latin1 avgt 15 63.254 ± 0.973 ns/op
StringReplace.replace1x1_0_UTF16 avgt 15 89.941 ± 3.210 ns/op
StringReplace.replace1x1_1_Latin1 avgt 15 75.662 ± 0.344 ns/op
StringReplace.replace1x1_1_UTF16 avgt 15 81.454 ± 1.986 ns/op
StringReplace.replace1x1_2_Latin1 avgt 15 89.492 ± 1.889 ns/op
StringReplace.replace1x1_2_UTF16 avgt 15 87.430 ± 1.341 ns/op
StringReplace.replace2x1_0_Latin1 avgt 15 69.575 ± 0.368 ns/op
StringReplace.replace2x1_0_UTF16 avgt 15 112.201 ± 2.836 ns/op
StringReplace.replace2x1_1_Latin1 avgt 15 83.841 ± 0.940 ns/op
StringReplace.replace2x1_1_UTF16 avgt 15 115.722 ± 2.267 ns/op
StringReplace.replace2x1_2_Latin1 avgt 15 99.266 ± 1.008 ns/op
StringReplace.replace2x1_2_UTF16 avgt 15 132.271 ± 2.365 ns/op
- after fix:
Benchmark Mode Cnt Score Error Units
StringReplace.replace0x1_1_Latin1 avgt 15 10.541 ± 0.826 ns/op x0.68
StringReplace.replace0x1_1_UTF16 avgt 15 31.473 ± 0.389 ns/op x2.68
StringReplace.replace1x1_0_Latin1 avgt 15 50.455 ± 5.038 ns/op x1.25
StringReplace.replace1x1_0_UTF16 avgt 15 35.355 ± 0.074 ns/op x2.54
StringReplace.replace1x1_1_Latin1 avgt 15 22.868 ± 0.076 ns/op x3.31
StringReplace.replace1x1_1_UTF16 avgt 15 22.290 ± 1.913 ns/op x3.65
StringReplace.replace1x1_2_Latin1 avgt 15 51.362 ± 0.130 ns/op x1.74
StringReplace.replace1x1_2_UTF16 avgt 15 33.086 ± 0.088 ns/op x2.64
StringReplace.replace2x1_0_Latin1 avgt 15 57.169 ± 7.165 ns/op x1.22
StringReplace.replace2x1_0_UTF16 avgt 15 50.886 ± 1.193 ns/op x2.20
StringReplace.replace2x1_1_Latin1 avgt 15 23.320 ± 2.954 ns/op x3.60
StringReplace.replace2x1_1_UTF16 avgt 15 24.741 ± 0.229 ns/op x4.68
StringReplace.replace2x1_2_Latin1 avgt 15 56.045 ± 0.153 ns/op x1.77
StringReplace.replace2x1_2_UTF16 avgt 15 49.795 ± 0.178 ns/op x2.66
--
With kind regards,
Ivan Gerasimov
--
With kind regards,
Ivan Gerasimov
