Re: RFR: 8334328: Reduce object allocation for FloatToDecimal and DoubleToDecimal [v20]
On Wed, 26 Jun 2024 14:55:44 GMT, Shaojin Wen wrote:
>> The current versions of FloatToDecimal and DoubleToDecimal allocate
>> additional objects. Reducing these allocations can improve the performance
>> of Float/Double.toString and AbstractStringBuilder's append(float/double).
>>
>> This patch is just a code refactoring to reduce object allocation, but does
>> not change the Float/Double to decimal algorithm.
>>
>> The following code comments the allocated objects to be removed.
>>
>>
>> class FloatToDecimal {
>> public static String toString(float v) {
>> // allocate object FloatToDecimal
>> return new FloatToDecimal().toDecimalString(v);
>> }
>>
>> public static Appendable appendTo(float v, Appendable app)
>> throws IOException {
>> // allocate object FloatToDecimal
>> return new FloatToDecimal().appendDecimalTo(v, app);
>> }
>>
>> private Appendable appendDecimalTo(float v, Appendable app)
>> throws IOException {
>> switch (toDecimal(v)) {
>> case NON_SPECIAL:
>> // allocate object char[]
>> char[] chars = new char[index + 1];
>> for (int i = 0; i < chars.length; ++i) {
>> chars[i] = (char) bytes[i];
>> }
>> if (app instanceof StringBuilder builder) {
>> return builder.append(chars);
>> }
>> if (app instanceof StringBuffer buffer) {
>> return buffer.append(chars);
>> }
>> for (char c : chars) {
>> app.append(c);
>> }
>> return app;
>> // ...
>> }
>> }
>> }
>>
>> class DoubleToDecimal {
>> public static String toString(double v) {
>> // allocate object DoubleToDecimal
>> return new DoubleToDecimal(false).toDecimalString(v);
>> }
>>
>> public static Appendable appendTo(double v, Appendable app)
>> throws IOException {
>> // allocate object DoubleToDecimal
>> return new DoubleToDecimal(false).appendDecimalTo(v, app);
>> }
>>
>> private Appendable appendDecimalTo(double v, Appendable app)
>> throws IOException {
>> switch (toDecimal(v, null)) {
>> case NON_SPECIAL:
>> // allocate object char[]
>> char[] chars = new char[index + 1];
>> for (int i = 0; i < chars.length; ++i) {
>> chars[i] = (char) bytes[i];
>> }
>> ...
>
> Shaojin Wen has updated the pull request incrementally with one additional
> commit since the last revision:
>
> 1. revert code change.
> 2. comment remove space
Tier 1-3 tests look good. Thanks Wen Shaojin!
-
PR Comment: https://git.openjdk.org/jdk/pull/19730#issuecomment-2193714370
Re: RFR: 8334328: Reduce object allocation for FloatToDecimal and DoubleToDecimal [v20]
On Wed, 26 Jun 2024 17:42:13 GMT, Chen Liang wrote:
>> Shaojin Wen has updated the pull request incrementally with one additional
>> commit since the last revision:
>>
>> 1. revert code change.
>> 2. comment remove space
>
> src/java.base/share/classes/jdk/internal/math/DoubleToDecimal.java line 194:
>
>> 192: * otherwise NON_SPECIAL
>> 193: */
>> 194: private int toDecimal(byte[] str, int index, double v,
>> FormattedFPDecimal fd) {
>
> This `toDecimal` returns packed int with info but the other returns the new
> index; this is extremely confusing for future readers, especially that they
> have very similar signatures (difference in signature is in the middle). I
> recommend making this return a `long` so when it's downcasted to an int, it's
> just the size (like String concat's coderIndex)
The maximum length of float to decimal is 15, and the maximum length of double
to decimal is 24, so one byte is enough. If we use the long return type, we
have to add `cast int to long` and `cast long to int` to the code, which is
redundant. It will also confuse people, thinking that float to decimal and
double to decimal will have a large length, just like the size of string
concat, which requires a complete int.
-
PR Review Comment: https://git.openjdk.org/jdk/pull/19730#discussion_r1655573216
Re: RFR: 8334328: Reduce object allocation for FloatToDecimal and DoubleToDecimal [v20]
On Wed, 26 Jun 2024 14:55:44 GMT, Shaojin Wen wrote:
>> The current versions of FloatToDecimal and DoubleToDecimal allocate
>> additional objects. Reducing these allocations can improve the performance
>> of Float/Double.toString and AbstractStringBuilder's append(float/double).
>>
>> This patch is just a code refactoring to reduce object allocation, but does
>> not change the Float/Double to decimal algorithm.
>>
>> The following code comments the allocated objects to be removed.
>>
>>
>> class FloatToDecimal {
>> public static String toString(float v) {
>> // allocate object FloatToDecimal
>> return new FloatToDecimal().toDecimalString(v);
>> }
>>
>> public static Appendable appendTo(float v, Appendable app)
>> throws IOException {
>> // allocate object FloatToDecimal
>> return new FloatToDecimal().appendDecimalTo(v, app);
>> }
>>
>> private Appendable appendDecimalTo(float v, Appendable app)
>> throws IOException {
>> switch (toDecimal(v)) {
>> case NON_SPECIAL:
>> // allocate object char[]
>> char[] chars = new char[index + 1];
>> for (int i = 0; i < chars.length; ++i) {
>> chars[i] = (char) bytes[i];
>> }
>> if (app instanceof StringBuilder builder) {
>> return builder.append(chars);
>> }
>> if (app instanceof StringBuffer buffer) {
>> return buffer.append(chars);
>> }
>> for (char c : chars) {
>> app.append(c);
>> }
>> return app;
>> // ...
>> }
>> }
>> }
>>
>> class DoubleToDecimal {
>> public static String toString(double v) {
>> // allocate object DoubleToDecimal
>> return new DoubleToDecimal(false).toDecimalString(v);
>> }
>>
>> public static Appendable appendTo(double v, Appendable app)
>> throws IOException {
>> // allocate object DoubleToDecimal
>> return new DoubleToDecimal(false).appendDecimalTo(v, app);
>> }
>>
>> private Appendable appendDecimalTo(double v, Appendable app)
>> throws IOException {
>> switch (toDecimal(v, null)) {
>> case NON_SPECIAL:
>> // allocate object char[]
>> char[] chars = new char[index + 1];
>> for (int i = 0; i < chars.length; ++i) {
>> chars[i] = (char) bytes[i];
>> }
>> ...
>
> Shaojin Wen has updated the pull request incrementally with one additional
> commit since the last revision:
>
> 1. revert code change.
> 2. comment remove space
LGTM2
-
Marked as reviewed by redestad (Reviewer).
PR Review: https://git.openjdk.org/jdk/pull/19730#pullrequestreview-2142672406
Re: RFR: 8334328: Reduce object allocation for FloatToDecimal and DoubleToDecimal [v20]
On Wed, 26 Jun 2024 14:55:44 GMT, Shaojin Wen wrote:
>> The current versions of FloatToDecimal and DoubleToDecimal allocate
>> additional objects. Reducing these allocations can improve the performance
>> of Float/Double.toString and AbstractStringBuilder's append(float/double).
>>
>> This patch is just a code refactoring to reduce object allocation, but does
>> not change the Float/Double to decimal algorithm.
>>
>> The following code comments the allocated objects to be removed.
>>
>>
>> class FloatToDecimal {
>> public static String toString(float v) {
>> // allocate object FloatToDecimal
>> return new FloatToDecimal().toDecimalString(v);
>> }
>>
>> public static Appendable appendTo(float v, Appendable app)
>> throws IOException {
>> // allocate object FloatToDecimal
>> return new FloatToDecimal().appendDecimalTo(v, app);
>> }
>>
>> private Appendable appendDecimalTo(float v, Appendable app)
>> throws IOException {
>> switch (toDecimal(v)) {
>> case NON_SPECIAL:
>> // allocate object char[]
>> char[] chars = new char[index + 1];
>> for (int i = 0; i < chars.length; ++i) {
>> chars[i] = (char) bytes[i];
>> }
>> if (app instanceof StringBuilder builder) {
>> return builder.append(chars);
>> }
>> if (app instanceof StringBuffer buffer) {
>> return buffer.append(chars);
>> }
>> for (char c : chars) {
>> app.append(c);
>> }
>> return app;
>> // ...
>> }
>> }
>> }
>>
>> class DoubleToDecimal {
>> public static String toString(double v) {
>> // allocate object DoubleToDecimal
>> return new DoubleToDecimal(false).toDecimalString(v);
>> }
>>
>> public static Appendable appendTo(double v, Appendable app)
>> throws IOException {
>> // allocate object DoubleToDecimal
>> return new DoubleToDecimal(false).appendDecimalTo(v, app);
>> }
>>
>> private Appendable appendDecimalTo(double v, Appendable app)
>> throws IOException {
>> switch (toDecimal(v, null)) {
>> case NON_SPECIAL:
>> // allocate object char[]
>> char[] chars = new char[index + 1];
>> for (int i = 0; i < chars.length; ++i) {
>> chars[i] = (char) bytes[i];
>> }
>> ...
>
> Shaojin Wen has updated the pull request incrementally with one additional
> commit since the last revision:
>
> 1. revert code change.
> 2. comment remove space
Changes requested by liach (Committer).
src/java.base/share/classes/jdk/internal/math/DoubleToDecimal.java line 194:
> 192: * otherwise NON_SPECIAL
> 193: */
> 194: private int toDecimal(byte[] str, int index, double v,
> FormattedFPDecimal fd) {
This `toDecimal` returns packed int with info but the other returns the new
index; this is extremely confusing for future readers, especially that they
have very similar signatures (difference in signature is in the middle). I
recommend making this return a `long` so when it's downcasted to an int, it's
just the size (like String concat's coderIndex)
-
PR Review: https://git.openjdk.org/jdk/pull/19730#pullrequestreview-2142568839
PR Review Comment: https://git.openjdk.org/jdk/pull/19730#discussion_r1655287303
Re: RFR: 8334328: Reduce object allocation for FloatToDecimal and DoubleToDecimal [v20]
On Wed, 26 Jun 2024 14:55:44 GMT, Shaojin Wen wrote:
>> The current versions of FloatToDecimal and DoubleToDecimal allocate
>> additional objects. Reducing these allocations can improve the performance
>> of Float/Double.toString and AbstractStringBuilder's append(float/double).
>>
>> This patch is just a code refactoring to reduce object allocation, but does
>> not change the Float/Double to decimal algorithm.
>>
>> The following code comments the allocated objects to be removed.
>>
>>
>> class FloatToDecimal {
>> public static String toString(float v) {
>> // allocate object FloatToDecimal
>> return new FloatToDecimal().toDecimalString(v);
>> }
>>
>> public static Appendable appendTo(float v, Appendable app)
>> throws IOException {
>> // allocate object FloatToDecimal
>> return new FloatToDecimal().appendDecimalTo(v, app);
>> }
>>
>> private Appendable appendDecimalTo(float v, Appendable app)
>> throws IOException {
>> switch (toDecimal(v)) {
>> case NON_SPECIAL:
>> // allocate object char[]
>> char[] chars = new char[index + 1];
>> for (int i = 0; i < chars.length; ++i) {
>> chars[i] = (char) bytes[i];
>> }
>> if (app instanceof StringBuilder builder) {
>> return builder.append(chars);
>> }
>> if (app instanceof StringBuffer buffer) {
>> return buffer.append(chars);
>> }
>> for (char c : chars) {
>> app.append(c);
>> }
>> return app;
>> // ...
>> }
>> }
>> }
>>
>> class DoubleToDecimal {
>> public static String toString(double v) {
>> // allocate object DoubleToDecimal
>> return new DoubleToDecimal(false).toDecimalString(v);
>> }
>>
>> public static Appendable appendTo(double v, Appendable app)
>> throws IOException {
>> // allocate object DoubleToDecimal
>> return new DoubleToDecimal(false).appendDecimalTo(v, app);
>> }
>>
>> private Appendable appendDecimalTo(double v, Appendable app)
>> throws IOException {
>> switch (toDecimal(v, null)) {
>> case NON_SPECIAL:
>> // allocate object char[]
>> char[] chars = new char[index + 1];
>> for (int i = 0; i < chars.length; ++i) {
>> chars[i] = (char) bytes[i];
>> }
>> ...
>
> Shaojin Wen has updated the pull request incrementally with one additional
> commit since the last revision:
>
> 1. revert code change.
> 2. comment remove space
LGTM
-
Marked as reviewed by rgiulietti (Reviewer).
PR Review: https://git.openjdk.org/jdk/pull/19730#pullrequestreview-2142544887
Re: RFR: 8334328: Reduce object allocation for FloatToDecimal and DoubleToDecimal [v20]
> The current versions of FloatToDecimal and DoubleToDecimal allocate
> additional objects. Reducing these allocations can improve the performance of
> Float/Double.toString and AbstractStringBuilder's append(float/double).
>
> This patch is just a code refactoring to reduce object allocation, but does
> not change the Float/Double to decimal algorithm.
>
> The following code comments the allocated objects to be removed.
>
>
> class FloatToDecimal {
> public static String toString(float v) {
> // allocate object FloatToDecimal
> return new FloatToDecimal().toDecimalString(v);
> }
>
> public static Appendable appendTo(float v, Appendable app)
> throws IOException {
> // allocate object FloatToDecimal
> return new FloatToDecimal().appendDecimalTo(v, app);
> }
>
> private Appendable appendDecimalTo(float v, Appendable app)
> throws IOException {
> switch (toDecimal(v)) {
> case NON_SPECIAL:
> // allocate object char[]
> char[] chars = new char[index + 1];
> for (int i = 0; i < chars.length; ++i) {
> chars[i] = (char) bytes[i];
> }
> if (app instanceof StringBuilder builder) {
> return builder.append(chars);
> }
> if (app instanceof StringBuffer buffer) {
> return buffer.append(chars);
> }
> for (char c : chars) {
> app.append(c);
> }
> return app;
> // ...
> }
> }
> }
>
> class DoubleToDecimal {
> public static String toString(double v) {
> // allocate object DoubleToDecimal
> return new DoubleToDecimal(false).toDecimalString(v);
> }
>
> public static Appendable appendTo(double v, Appendable app)
> throws IOException {
> // allocate object DoubleToDecimal
> return new DoubleToDecimal(false).appendDecimalTo(v, app);
> }
>
> private Appendable appendDecimalTo(double v, Appendable app)
> throws IOException {
> switch (toDecimal(v, null)) {
> case NON_SPECIAL:
> // allocate object char[]
> char[] chars = new char[index + 1];
> for (int i = 0; i < chars.length; ++i) {
> chars[i] = (char) bytes[i];
> }
> if (app instanceof StringBuilder builder) {
> return builder.append(chars);
> }
> ...
Shaojin Wen has updated the pull request incrementally with one additional
commit since the last revision:
1. revert code change.
2. comment remove space
-
Changes:
- all: https://git.openjdk.org/jdk/pull/19730/files
- new: https://git.openjdk.org/jdk/pull/19730/files/a3d216dd..b4f2d875
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk=19730=19
- incr: https://webrevs.openjdk.org/?repo=jdk=19730=18-19
Stats: 7 lines in 2 files changed: 0 ins; 3 del; 4 mod
Patch: https://git.openjdk.org/jdk/pull/19730.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/19730/head:pull/19730
PR: https://git.openjdk.org/jdk/pull/19730
