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Use byte padding to avoid fields re-ordering on JDK 15 and above #3168

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merged 12 commits into from
Aug 29, 2022
Merged

Use byte padding to avoid fields re-ordering on JDK 15 and above #3168

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9a0f4ff
Replace 'long' padding by 'byte' padding to avoid re-ordering on mode…
lantalex Aug 24, 2022
65747a9
Update license header
lantalex Aug 25, 2022
fc14627
Replace 'long' padding for QueueDrainSubscriber
lantalex Aug 26, 2022
f381459
Replace the QueueDrainSubscriber#objectLayout() test with the simplif…
lantalex Aug 26, 2022
f23ab52
Use 'pad' prefix for padding field names
lantalex Aug 26, 2022
0eba668
Add object layout test for SpscArrayQueue
lantalex Aug 26, 2022
3d8ef21
Extend padding for QueueDrainSubscriber + update test
lantalex Aug 28, 2022
ab0fa1d
Making SpscArrayQueue internal padding consistent for actual versions…
lantalex Aug 28, 2022
c58af9d
Fix alignment
lantalex Aug 29, 2022
915a8b4
Add `unused` annotation for padding fields
lantalex Aug 29, 2022
4420d41
Add `unused` annotation for padding fields
lantalex Aug 29, 2022
463c559
Remove unnecessary `public` modifier
lantalex Aug 29, 2022
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59 changes: 52 additions & 7 deletions reactor-core/src/main/java/reactor/core/publisher/QueueDrainSubscriber.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2018-2021 VMware Inc. or its affiliates, All Rights Reserved.
* Copyright (c) 2018-2022 VMware Inc. or its affiliates, All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand Down Expand Up @@ -284,9 +284,24 @@ static <Q, S> boolean checkTerminated(boolean d, boolean empty,
//-------------------------------------------------------------------

/** Pads the header away from other fields. */
@SuppressWarnings("unused")
class QueueDrainSubscriberPad0 {
volatile long p1, p2, p3, p4, p5, p6, p7;
volatile long p8, p9, p10, p11, p12, p13, p14, p15;
byte pad000,pad001,pad002,pad003,pad004,pad005,pad006,pad007;// 8b
byte pad010,pad011,pad012,pad013,pad014,pad015,pad016,pad017;// 16b
byte pad020,pad021,pad022,pad023,pad024,pad025,pad026,pad027;// 24b
byte pad030,pad031,pad032,pad033,pad034,pad035,pad036,pad037;// 32b
byte pad040,pad041,pad042,pad043,pad044,pad045,pad046,pad047;// 40b
byte pad050,pad051,pad052,pad053,pad054,pad055,pad056,pad057;// 48b
byte pad060,pad061,pad062,pad063,pad064,pad065,pad066,pad067;// 56b
byte pad070,pad071,pad072,pad073,pad074,pad075,pad076,pad077;// 64b
byte pad100,pad101,pad102,pad103,pad104,pad105,pad106,pad107;// 72b
byte pad110,pad111,pad112,pad113,pad114,pad115,pad116,pad117;// 80b
byte pad120,pad121,pad122,pad123,pad124,pad125,pad126,pad127;// 88b
byte pad130,pad131,pad132,pad133,pad134,pad135,pad136,pad137;// 96b
byte pad140,pad141,pad142,pad143,pad144,pad145,pad146,pad147;//104b
byte pad150,pad151,pad152,pad153,pad154,pad155,pad156,pad157;//112b
byte pad160,pad161,pad162,pad163,pad164,pad165,pad166,pad167;//120b
byte pad170,pad171,pad172,pad173,pad174,pad175,pad176,pad177;//128b
}

/** The WIP counter. */
Expand All @@ -295,9 +310,24 @@ class QueueDrainSubscriberWip extends QueueDrainSubscriberPad0 {
}

/** Pads away the wip from the other fields. */
@SuppressWarnings("unused")
class QueueDrainSubscriberPad2 extends QueueDrainSubscriberWip {
volatile long p1a, p2a, p3a, p4a, p5a, p6a, p7a;
volatile long p8a, p9a, p10a, p11a, p12a, p13a, p14a, p15a;
byte pad000,pad001,pad002,pad003,pad004,pad005,pad006,pad007;// 8b
byte pad010,pad011,pad012,pad013,pad014,pad015,pad016,pad017;// 16b
byte pad020,pad021,pad022,pad023,pad024,pad025,pad026,pad027;// 24b
byte pad030,pad031,pad032,pad033,pad034,pad035,pad036,pad037;// 32b
byte pad040,pad041,pad042,pad043,pad044,pad045,pad046,pad047;// 40b
byte pad050,pad051,pad052,pad053,pad054,pad055,pad056,pad057;// 48b
byte pad060,pad061,pad062,pad063,pad064,pad065,pad066,pad067;// 56b
byte pad070,pad071,pad072,pad073,pad074,pad075,pad076,pad077;// 64b
byte pad100,pad101,pad102,pad103,pad104,pad105,pad106,pad107;// 72b
byte pad110,pad111,pad112,pad113,pad114,pad115,pad116,pad117;// 80b
byte pad120,pad121,pad122,pad123,pad124,pad125,pad126,pad127;// 88b
byte pad130,pad131,pad132,pad133,pad134,pad135,pad136,pad137;// 96b
byte pad140,pad141,pad142,pad143,pad144,pad145,pad146,pad147;//104b
byte pad150,pad151,pad152,pad153,pad154,pad155,pad156,pad157;//112b
byte pad160,pad161,pad162,pad163,pad164,pad165,pad166,pad167;//120b
byte pad170,pad171,pad172,pad173,pad174,pad175,pad176,pad177;//128b
}

/** Contains the requested field. */
Expand All @@ -310,7 +340,22 @@ class QueueDrainSubscriberPad3 extends QueueDrainSubscriberPad2 {
}

/** Pads away the requested from the other fields. */
@SuppressWarnings("unused")
class QueueDrainSubscriberPad4 extends QueueDrainSubscriberPad3 {
volatile long q1, q2, q3, q4, q5, q6, q7;
volatile long q8, q9, q10, q11, q12, q13, q14, q15;
byte pad000,pad001,pad002,pad003,pad004,pad005,pad006,pad007;// 8b
byte pad010,pad011,pad012,pad013,pad014,pad015,pad016,pad017;// 16b
byte pad020,pad021,pad022,pad023,pad024,pad025,pad026,pad027;// 24b
byte pad030,pad031,pad032,pad033,pad034,pad035,pad036,pad037;// 32b
byte pad040,pad041,pad042,pad043,pad044,pad045,pad046,pad047;// 40b
byte pad050,pad051,pad052,pad053,pad054,pad055,pad056,pad057;// 48b
byte pad060,pad061,pad062,pad063,pad064,pad065,pad066,pad067;// 56b
byte pad070,pad071,pad072,pad073,pad074,pad075,pad076,pad077;// 64b
byte pad100,pad101,pad102,pad103,pad104,pad105,pad106,pad107;// 72b
byte pad110,pad111,pad112,pad113,pad114,pad115,pad116,pad117;// 80b
byte pad120,pad121,pad122,pad123,pad124,pad125,pad126,pad127;// 88b
byte pad130,pad131,pad132,pad133,pad134,pad135,pad136,pad137;// 96b
byte pad140,pad141,pad142,pad143,pad144,pad145,pad146,pad147;//104b
byte pad150,pad151,pad152,pad153,pad154,pad155,pad156,pad157;//112b
byte pad160,pad161,pad162,pad163,pad164,pad165,pad166,pad167;//120b
byte pad170,pad171,pad172,pad173,pad174,pad175,pad176,pad177;//128b
}
65 changes: 55 additions & 10 deletions reactor-core/src/main/java/reactor/util/concurrent/SpscArrayQueue.java
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2016-2021 VMware Inc. or its affiliates, All Rights Reserved.
* Copyright (c) 2016-2022 VMware Inc. or its affiliates, All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand Down Expand Up @@ -175,13 +175,28 @@ public SpscArrayQueueCold(int length) {
mask = length - 1;
}
}
@SuppressWarnings("unused")
class SpscArrayQueueP1<T> extends SpscArrayQueueCold<T> {
/** */
private static final long serialVersionUID = -4461305682174876914L;

long p00, p01, p02, p03, p04, p05, p06, p07;
long p08, p09, p0A, p0B, p0C, p0D, p0E;

byte pad000,pad001,pad002,pad003,pad004,pad005,pad006,pad007;// 8b
byte pad010,pad011,pad012,pad013,pad014,pad015,pad016,pad017;// 16b
byte pad020,pad021,pad022,pad023,pad024,pad025,pad026,pad027;// 24b
byte pad030,pad031,pad032,pad033,pad034,pad035,pad036,pad037;// 32b
byte pad040,pad041,pad042,pad043,pad044,pad045,pad046,pad047;// 40b
byte pad050,pad051,pad052,pad053,pad054,pad055,pad056,pad057;// 48b
byte pad060,pad061,pad062,pad063,pad064,pad065,pad066,pad067;// 56b
byte pad070,pad071,pad072,pad073,pad074,pad075,pad076,pad077;// 64b
byte pad100,pad101,pad102,pad103,pad104,pad105,pad106,pad107;// 72b
byte pad110,pad111,pad112,pad113,pad114,pad115,pad116,pad117;// 80b
byte pad120,pad121,pad122,pad123,pad124,pad125,pad126,pad127;// 88b
byte pad130,pad131,pad132,pad133,pad134,pad135,pad136,pad137;// 96b
byte pad140,pad141,pad142,pad143,pad144,pad145,pad146,pad147;//104b
byte pad150,pad151,pad152,pad153,pad154,pad155,pad156,pad157;//112b
byte pad160,pad161,pad162,pad163,pad164,pad165,pad166,pad167;//120b
byte pad170,pad171,pad172,pad173,pad174,pad175,pad176,pad177;//128b
byte pad200,pad201,pad202,pad203; //132b
SpscArrayQueueP1(int length) {
super(length);
}
Expand All @@ -203,12 +218,27 @@ class SpscArrayQueueProducer<T> extends SpscArrayQueueP1<T> {

}

@SuppressWarnings("unused")
class SpscArrayQueueP2<T> extends SpscArrayQueueProducer<T> {
/** */
private static final long serialVersionUID = -5400235061461013116L;

long p00, p01, p02, p03, p04, p05, p06, p07;
long p08, p09, p0A, p0B, p0C, p0D, p0E;

byte pad000,pad001,pad002,pad003,pad004,pad005,pad006,pad007;// 8b
byte pad010,pad011,pad012,pad013,pad014,pad015,pad016,pad017;// 16b
byte pad020,pad021,pad022,pad023,pad024,pad025,pad026,pad027;// 24b
byte pad030,pad031,pad032,pad033,pad034,pad035,pad036,pad037;// 32b
byte pad040,pad041,pad042,pad043,pad044,pad045,pad046,pad047;// 40b
byte pad050,pad051,pad052,pad053,pad054,pad055,pad056,pad057;// 48b
byte pad060,pad061,pad062,pad063,pad064,pad065,pad066,pad067;// 56b
byte pad070,pad071,pad072,pad073,pad074,pad075,pad076,pad077;// 64b
byte pad100,pad101,pad102,pad103,pad104,pad105,pad106,pad107;// 72b
byte pad110,pad111,pad112,pad113,pad114,pad115,pad116,pad117;// 80b
byte pad120,pad121,pad122,pad123,pad124,pad125,pad126,pad127;// 88b
byte pad130,pad131,pad132,pad133,pad134,pad135,pad136,pad137;// 96b
byte pad140,pad141,pad142,pad143,pad144,pad145,pad146,pad147;//104b
byte pad150,pad151,pad152,pad153,pad154,pad155,pad156,pad157;//112b
byte pad160,pad161,pad162,pad163,pad164,pad165,pad166,pad167;//120b
byte pad170,pad171,pad172,pad173,pad174,pad175,pad176,pad177;//128b

SpscArrayQueueP2(int length) {
super(length);
Expand All @@ -231,12 +261,27 @@ class SpscArrayQueueConsumer<T> extends SpscArrayQueueP2<T> {

}

@SuppressWarnings("unused")
class SpscArrayQueueP3<T> extends SpscArrayQueueConsumer<T> {
/** */
private static final long serialVersionUID = -2684922090021364171L;

long p00, p01, p02, p03, p04, p05, p06, p07;
long p08, p09, p0A, p0B, p0C, p0D, p0E;

byte pad000,pad001,pad002,pad003,pad004,pad005,pad006,pad007;// 8b
byte pad010,pad011,pad012,pad013,pad014,pad015,pad016,pad017;// 16b
byte pad020,pad021,pad022,pad023,pad024,pad025,pad026,pad027;// 24b
byte pad030,pad031,pad032,pad033,pad034,pad035,pad036,pad037;// 32b
byte pad040,pad041,pad042,pad043,pad044,pad045,pad046,pad047;// 40b
byte pad050,pad051,pad052,pad053,pad054,pad055,pad056,pad057;// 48b
byte pad060,pad061,pad062,pad063,pad064,pad065,pad066,pad067;// 56b
byte pad070,pad071,pad072,pad073,pad074,pad075,pad076,pad077;// 64b
byte pad100,pad101,pad102,pad103,pad104,pad105,pad106,pad107;// 72b
byte pad110,pad111,pad112,pad113,pad114,pad115,pad116,pad117;// 80b
byte pad120,pad121,pad122,pad123,pad124,pad125,pad126,pad127;// 88b
byte pad130,pad131,pad132,pad133,pad134,pad135,pad136,pad137;// 96b
byte pad140,pad141,pad142,pad143,pad144,pad145,pad146,pad147;//104b
byte pad150,pad151,pad152,pad153,pad154,pad155,pad156,pad157;//112b
byte pad160,pad161,pad162,pad163,pad164,pad165,pad166,pad167;//120b
byte pad170,pad171,pad172,pad173,pad174,pad175,pad176,pad177;//128b

SpscArrayQueueP3(int length) {
super(length);
Expand Down
78 changes: 35 additions & 43 deletions reactor-core/src/test/java/reactor/core/publisher/QueueDrainSubscriberTest.java
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2018-2021 VMware Inc. or its affiliates, All Rights Reserved.
* Copyright (c) 2018-2022 VMware Inc. or its affiliates, All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand All @@ -16,64 +16,56 @@

package reactor.core.publisher;

import java.util.concurrent.atomic.AtomicReference;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicLong;

import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;
import org.openjdk.jol.info.ClassLayout;
import org.openjdk.jol.info.FieldLayout;

import static org.assertj.core.api.Assertions.assertThat;

public class QueueDrainSubscriberTest {

@Test
@Tag("slow")
public void objectPadding() {
void objectPadding() {
ClassLayout layout = ClassLayout.parseClass(QueueDrainSubscriber.class);
AtomicReference<FieldLayout> wip = new AtomicReference<>();
AtomicReference<FieldLayout> requested = new AtomicReference<>();

AtomicLong currentPaddingSize = new AtomicLong();
List<String> fields = new ArrayList<>();
List<Long> paddingSizes = new ArrayList<>();

layout.fields().forEach(f -> {
if ("wip".equals(f.name())) wip.set(f);
else if ("requested".equals(f.name())) requested.set(f);
if (f.name().startsWith("pad")) {
currentPaddingSize.addAndGet(f.size());
} else {
if (currentPaddingSize.get() > 0) {
fields.add("[padding]");
paddingSizes.add(currentPaddingSize.getAndSet(0));
}
fields.add(f.name());
}
});
if (currentPaddingSize.get() > 0) {
fields.add("[padding]");
paddingSizes.add(currentPaddingSize.getAndSet(0));
}

final FieldLayout fieldAfterRequested = layout.fields()
.tailSet(requested.get())
.stream()
.skip(1)
.filter(fl -> fl.name().length() >= 4)
.findFirst()
.get();

assertThat(layout.fields().headSet(wip.get()))
.as("wip pre-padding")
.hasSize(15)
.allSatisfy(fl -> assertThat(fl.name()).startsWith("p"));

assertThat(layout.fields().subSet(wip.get(), requested.get()).stream().skip(1))
.as("wip-requested padding")
.hasSize(15)
.allSatisfy(fl -> assertThat(fl.name()).startsWith("p").endsWith("a"));
assertThat(fields).containsExactly(
"[padding]",
"wip",
"[padding]",
"requested",
"[padding]",
"cancelled",
"done",
"actual",
"queue",
"error"
);

assertThat(layout.fields().subSet(requested.get(), fieldAfterRequested)
.stream()
.skip(1))
.as("requested post-padding")
.hasSize(15)
.allSatisfy(fl -> assertThat(fl.name()).startsWith("q").isNotEqualTo("queue"));

assertThat(wip.get().offset())
.as("wip offset")
.isEqualTo(136);
assertThat(requested.get().offset())
.as("requested offset")
.isEqualTo(wip.get().offset() + 128);

System.out.println(wip.get());
System.out.println(requested.get());
System.out.println(fieldAfterRequested);
assertThat(paddingSizes).containsExactly(128L, 128L, 128L);
}

}