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author | 2017-10-31 10:56:47 +0000 | |
---|---|---|
committer | 2019-05-16 14:44:09 +0000 | |
commit | 552a13415573da19eafa46e1ac00fb0eb68f2b23 (patch) | |
tree | 8cae5f3602d8f8e65cd3cbc349af17d785128605 /benchmark/stringbuilder-append/src/StringBuilderAppendBenchmark.java | |
parent | 0dda8c84938d6bb4ce5a1707e5e109ea187fc33d (diff) |
ART: Optimize StringBuilder append pattern.
Recognize appending with StringBuilder and replace the
entire expression with a runtime call that perfoms the
append in a more efficient manner.
For now, require the entire pattern to be in a single block
and be very strict about the StringBuilder environment uses.
Also, do not accept StringBuilder/char[]/Object/float/double
arguments as they throw non-OOME exceptions and/or require a
call from the entrypoint back to a helper function in Java;
these shall be implemented later.
Boot image size for aosp_taimen-userdebug:
- before:
arm/boot*.oat: 19653872
arm64/boot*.oat: 23292784
oat/arm64/services.odex: 22408664
- after:
arm/boot*.oat: 19432184 (-216KiB)
arm64/boot*.oat: 22992488 (-293KiB)
oat/arm64/services.odex: 22376776 (-31KiB)
Note that const-string in compiled boot image methods cannot
throw, but for apps it can and therefore its environment can
prevent the optimization for apps. We could implement either
a simple carve-out for const-string or generic environment
pruning to allow this pattern to be applied more often.
Results for the new StringBuilderAppendBenchmark on taimen:
timeAppendLongStrings: ~700ns -> ~200ns
timeAppendStringAndInt: ~220ns -> ~140ns
timeAppendStrings: ~200ns -> 130ns
Bug: 19575890
Test: 697-checker-string-append
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Test: aosp_taimen-userdebug boots.
Test: run-gtests.sh
Test: testrunner.py --target --optimizing
Test: vogar --benchmark art/benchmark/stringbuilder-append/src/StringBuilderAppendBenchmark.java
Change-Id: I51789bf299f5219f68ada4c077b6a1d3fe083964
Diffstat (limited to 'benchmark/stringbuilder-append/src/StringBuilderAppendBenchmark.java')
-rw-r--r-- | benchmark/stringbuilder-append/src/StringBuilderAppendBenchmark.java | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/benchmark/stringbuilder-append/src/StringBuilderAppendBenchmark.java b/benchmark/stringbuilder-append/src/StringBuilderAppendBenchmark.java new file mode 100644 index 0000000000..1550e81bf7 --- /dev/null +++ b/benchmark/stringbuilder-append/src/StringBuilderAppendBenchmark.java @@ -0,0 +1,62 @@ +/* + * Copyright (C) 2019 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +public class StringBuilderAppendBenchmark { + public static String string1 = "s1"; + public static String string2 = "s2"; + public static String longString1 = "This is a long string 1"; + public static String longString2 = "This is a long string 2"; + public static int int1 = 42; + + public void timeAppendStrings(int count) { + String s1 = string1; + String s2 = string2; + int sum = 0; + for (int i = 0; i < count; ++i) { + String result = s1 + s2; + sum += result.length(); // Make sure the append is not optimized away. + } + if (sum != count * (s1.length() + s2.length())) { + throw new AssertionError(); + } + } + + public void timeAppendLongStrings(int count) { + String s1 = longString1; + String s2 = longString2; + int sum = 0; + for (int i = 0; i < count; ++i) { + String result = s1 + s2; + sum += result.length(); // Make sure the append is not optimized away. + } + if (sum != count * (s1.length() + s2.length())) { + throw new AssertionError(); + } + } + + public void timeAppendStringAndInt(int count) { + String s1 = string1; + int i1 = int1; + int sum = 0; + for (int i = 0; i < count; ++i) { + String result = s1 + i1; + sum += result.length(); // Make sure the append is not optimized away. + } + if (sum != count * (s1.length() + Integer.toString(i1).length())) { + throw new AssertionError(); + } + } +} |