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HDDS-10489. Use CRC tables to speed up galoisFieldMultiply in CrcUtil. #10155

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Merged
szetszwo merged 2 commits into from
Apr 29, 2026
Merged

HDDS-10489. Use CRC tables to speed up galoisFieldMultiply in CrcUtil. #10155

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HDDS-10489. Use CRC tables to speed up galoisFieldMultiply in CrcUtil.
szetszwo Apr 26, 2026
ed79382
Use LongToIntFunction
szetszwo Apr 29, 2026
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12 changes: 12 additions & 0 deletions hadoop-hdds/common/src/main/java/org/apache/hadoop/ozone/common/PureJavaCrc32ByteBuffer.java
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Expand Up @@ -553,4 +553,16 @@ public final class PureJavaCrc32ByteBuffer extends ChecksumByteBuffer.CrcIntTabl
int[] getTable() {
return T;
}

/**
* Compute x mod p, where p is the CRC32 polynomial.
* @param x the input value
* @return x mod p
*/
public static int mod(long x) {
final int y = (int)(x);
return (int)(x >> 32)
^ ((T[((y << 24) >>> 24) + 0x300] ^ T[((y << 16) >>> 24) + 0x200])
^ (T[((y << 8) >>> 24) + 0x100] ^ T[((y /* */) >>> 24) /* */]));
}
}
12 changes: 12 additions & 0 deletions ...op-hdds/common/src/main/java/org/apache/hadoop/ozone/common/PureJavaCrc32CByteBuffer.java
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Expand Up @@ -557,4 +557,16 @@ public final class PureJavaCrc32CByteBuffer extends ChecksumByteBuffer.CrcIntTab
int[] getTable() {
return T;
}

/**
* Compute x mod p, where p is the CRC32C polynomial.
* @param x the input value
* @return x mod p
*/
public static int mod(long x) {
final int y = (int)(x);
return (int)(x >> 32)
^ ((T[((y << 24) >>> 24) + 0x300] ^ T[((y << 16) >>> 24) + 0x200])
^ (T[((y << 8) >>> 24) + 0x100] ^ T[((y /* */) >>> 24) /* */]));
}
}
49 changes: 25 additions & 24 deletions hadoop-ozone/common/src/main/java/org/apache/hadoop/ozone/client/checksum/CrcComposer.java
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Expand Up @@ -20,8 +20,11 @@
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.function.LongToIntFunction;
import org.apache.hadoop.hdds.annotation.InterfaceAudience;
import org.apache.hadoop.hdds.annotation.InterfaceStability;
import org.apache.hadoop.ozone.common.PureJavaCrc32ByteBuffer;
import org.apache.hadoop.ozone.common.PureJavaCrc32CByteBuffer;
import org.apache.hadoop.util.DataChecksum;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
Expand All @@ -34,11 +37,11 @@
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class CrcComposer {
public final class CrcComposer {
private static final int CRC_SIZE_BYTES = 4;
private static final Logger LOG = LoggerFactory.getLogger(CrcComposer.class);

private final int crcPolynomial;
private final LongToIntFunction mod;
private final int precomputedMonomialForHint;
private final long bytesPerCrcHint;
private final long stripeLength;
Expand Down Expand Up @@ -76,28 +79,26 @@ public static CrcComposer newCrcComposer(DataChecksum.Type type, long bytesPerCr
* underlying data size which aligns with the specified stripe boundary.
*/
public static CrcComposer newStripedCrcComposer(DataChecksum.Type type, long bytesPerCrcHint, long stripeLength) {
final int polynomial = CrcUtil.getCrcPolynomialForType(type);
return new CrcComposer(
polynomial,
CrcUtil.getMonomial(bytesPerCrcHint, polynomial),
bytesPerCrcHint,
stripeLength);
return new CrcComposer(type, bytesPerCrcHint, stripeLength);
}

CrcComposer(
int crcPolynomial,
int precomputedMonomialForHint,
long bytesPerCrcHint,
long stripeLength) {
LOG.debug(
"crcPolynomial=0x{}, precomputedMonomialForHint=0x{}, "
+ "bytesPerCrcHint={}, stripeLength={}",
Integer.toString(crcPolynomial, 16),
Integer.toString(precomputedMonomialForHint, 16),
bytesPerCrcHint,
stripeLength);
this.crcPolynomial = crcPolynomial;
this.precomputedMonomialForHint = precomputedMonomialForHint;
/** @return the mod function for the given type. */
static LongToIntFunction getModFunction(DataChecksum.Type type) {
switch (type) {
case CRC32:
return PureJavaCrc32ByteBuffer::mod;
case CRC32C:
return PureJavaCrc32CByteBuffer::mod;
default:
throw new IllegalArgumentException("Unexpected type: " + type);
}
}

private CrcComposer(DataChecksum.Type type, long bytesPerCrcHint, long stripeLength) {
LOG.debug("type={}, bytesPerCrcHint={}, stripeLength={}",
type, bytesPerCrcHint, stripeLength);
this.mod = getModFunction(type);
this.precomputedMonomialForHint = CrcUtil.getMonomial(bytesPerCrcHint, mod);
this.bytesPerCrcHint = bytesPerCrcHint;
this.stripeLength = stripeLength;
}
Expand Down Expand Up @@ -157,9 +158,9 @@ public void update(int crcB, long bytesPerCrc) {
if (curCompositeCrc == 0) {
curCompositeCrc = crcB;
} else if (bytesPerCrc == bytesPerCrcHint) {
curCompositeCrc = CrcUtil.composeWithMonomial(curCompositeCrc, crcB, precomputedMonomialForHint, crcPolynomial);
curCompositeCrc = CrcUtil.composeWithMonomial(curCompositeCrc, crcB, precomputedMonomialForHint, mod);
} else {
curCompositeCrc = CrcUtil.compose(curCompositeCrc, crcB, bytesPerCrc, crcPolynomial);
curCompositeCrc = CrcUtil.compose(curCompositeCrc, crcB, bytesPerCrc, mod);
}

curPositionInStripe += bytesPerCrc;
Expand Down
113 changes: 52 additions & 61 deletions hadoop-ozone/common/src/main/java/org/apache/hadoop/ozone/client/checksum/CrcUtil.java
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Expand Up @@ -18,9 +18,9 @@
package org.apache.hadoop.ozone.client.checksum;

import java.util.Arrays;
import java.util.function.LongToIntFunction;
import org.apache.hadoop.hdds.annotation.InterfaceAudience;
import org.apache.hadoop.hdds.annotation.InterfaceStability;
import org.apache.hadoop.util.DataChecksum;

/**
* This class provides utilities for working with CRCs.
Expand All @@ -29,8 +29,7 @@
@InterfaceStability.Unstable
public final class CrcUtil {
public static final int MULTIPLICATIVE_IDENTITY = 0x80000000;
public static final int GZIP_POLYNOMIAL = 0xEDB88320;
public static final int CASTAGNOLI_POLYNOMIAL = 0x82F63B78;
private static final long UNIT = 0x8000_0000_0000_0000L;

/**
* Hide default constructor for a static utils class.
Expand All @@ -39,22 +38,51 @@ private CrcUtil() {
}

/**
* getCrcPolynomialForType.
*
* @param type type.
* @return the int representation of the polynomial associated with the
* CRC {@code type}, suitable for use with further CRC arithmetic.
* @return a * b (mod p),
* where mod p is computed by the given mod function.
*/
public static int getCrcPolynomialForType(DataChecksum.Type type) {
switch (type) {
case CRC32:
return GZIP_POLYNOMIAL;
case CRC32C:
return CASTAGNOLI_POLYNOMIAL;
default:
throw new IllegalArgumentException(
"No CRC polynomial could be associated with type: " + type);
}
static int multiplyMod(int a, int b, LongToIntFunction mod) {
final long left = ((long)a) << 32;
final long right = ((long)b) << 32;

final long product
= ((((((left & (UNIT /* */)) == 0L ? 0L : right)
^ ((left & (UNIT >>> 1)) == 0L ? 0L : right >>> 1))
^ (((left & (UNIT >>> 2)) == 0L ? 0L : right >>> 2)
^ ((left & (UNIT >>> 3)) == 0L ? 0L : right >>> 3)))
^ ((((left & (UNIT >>> 4)) == 0L ? 0L : right >>> 4)
^ ((left & (UNIT >>> 5)) == 0L ? 0L : right >>> 5))
^ (((left & (UNIT >>> 6)) == 0L ? 0L : right >>> 6)
^ ((left & (UNIT >>> 7)) == 0L ? 0L : right >>> 7))))

^ (((((left & (UNIT >>> 8)) == 0L ? 0L : right >>> 8)
^ ((left & (UNIT >>> 9)) == 0L ? 0L : right >>> 9))
^ (((left & (UNIT >>> 10)) == 0L ? 0L : right >>> 10)
^ ((left & (UNIT >>> 11)) == 0L ? 0L : right >>> 11)))
^ ((((left & (UNIT >>> 12)) == 0L ? 0L : right >>> 12)
^ ((left & (UNIT >>> 13)) == 0L ? 0L : right >>> 13))
^ (((left & (UNIT >>> 14)) == 0L ? 0L : right >>> 14)
^ ((left & (UNIT >>> 15)) == 0L ? 0L : right >>> 15)))))

^ ((((((left & (UNIT >>> 16)) == 0L ? 0L : right >>> 16)
^ ((left & (UNIT >>> 17)) == 0L ? 0L : right >>> 17))
^ (((left & (UNIT >>> 18)) == 0L ? 0L : right >>> 18)
^ ((left & (UNIT >>> 19)) == 0L ? 0L : right >>> 19)))
^ ((((left & (UNIT >>> 20)) == 0L ? 0L : right >>> 20)
^ ((left & (UNIT >>> 21)) == 0L ? 0L : right >>> 21))
^ (((left & (UNIT >>> 22)) == 0L ? 0L : right >>> 22)
^ ((left & (UNIT >>> 23)) == 0L ? 0L : right >>> 23))))

^ (((((left & (UNIT >>> 24)) == 0L ? 0L : right >>> 24)
^ ((left & (UNIT >>> 25)) == 0L ? 0L : right >>> 25))
^ (((left & (UNIT >>> 26)) == 0L ? 0L : right >>> 26)
^ ((left & (UNIT >>> 27)) == 0L ? 0L : right >>> 27)))
^ ((((left & (UNIT >>> 28)) == 0L ? 0L : right >>> 28)
^ ((left & (UNIT >>> 29)) == 0L ? 0L : right >>> 29))
^ (((left & (UNIT >>> 30)) == 0L ? 0L : right >>> 30)
^ ((left & (UNIT >>> 31)) == 0L ? 0L : right >>> 31)))));

return mod.applyAsInt(product);
}

/**
Expand All @@ -66,7 +94,7 @@ public static int getCrcPolynomialForType(DataChecksum.Type type) {
* @param mod mod.
* @return monomial.
*/
public static int getMonomial(long lengthBytes, int mod) {
public static int getMonomial(long lengthBytes, LongToIntFunction mod) {
if (lengthBytes == 0) {
return MULTIPLICATIVE_IDENTITY;
} else if (lengthBytes < 0) {
Expand All @@ -85,9 +113,9 @@ public static int getMonomial(long lengthBytes, int mod) {
while (degree > 0) {
if ((degree & 1) != 0) {
product = (product == MULTIPLICATIVE_IDENTITY) ? multiplier :
galoisFieldMultiply(product, multiplier, mod);
multiplyMod(product, multiplier, mod);
}
multiplier = galoisFieldMultiply(multiplier, multiplier, mod);
multiplier = multiplyMod(multiplier, multiplier, mod);
degree >>= 1;
}
return product;
Expand All @@ -103,8 +131,8 @@ public static int getMonomial(long lengthBytes, int mod) {
* @return compose with monomial.
*/
public static int composeWithMonomial(
int crcA, int crcB, int monomial, int mod) {
return galoisFieldMultiply(crcA, monomial, mod) ^ crcB;
int crcA, int crcB, int monomial, LongToIntFunction mod) {
return multiplyMod(crcA, monomial, mod) ^ crcB;
}

/**
Expand All @@ -116,7 +144,7 @@ public static int composeWithMonomial(
* @param mod mod.
* @return compose result.
*/
public static int compose(int crcA, int crcB, long lengthB, int mod) {
public static int compose(int crcA, int crcB, long lengthB, LongToIntFunction mod) {
int monomial = getMonomial(lengthB, mod);
return composeWithMonomial(crcA, crcB, monomial, mod);
}
Expand Down Expand Up @@ -216,41 +244,4 @@ public static String toMultiCrcString(final byte[] bytes) {
sb.append(']');
return sb.toString();
}

/**
* Galois field multiplication of {@code p} and {@code q} with the
* generator polynomial {@code m} as the modulus.
*
* @param m The little-endian polynomial to use as the modulus when
* multiplying p and q, with implicit "1" bit beyond the bottom bit.
*/
private static int galoisFieldMultiply(int p, int q, int m) {
int summation = 0;

// Top bit is the x^0 place; each right-shift increments the degree of the
// current term.
int curTerm = MULTIPLICATIVE_IDENTITY;

// Iteratively multiply p by x mod m as we go to represent the q[i] term
// (of degree x^i) times p.
int px = p;

while (curTerm != 0) {
if ((q & curTerm) != 0) {
summation ^= px;
}

// Bottom bit represents highest degree since we're little-endian; before
// we multiply by "x" for the next term, check bottom bit to know whether
// the resulting px will thus have a term matching the implicit "1" term
// of "m" and thus will need to subtract "m" after mutiplying by "x".
boolean hasMaxDegree = ((px & 1) != 0);
px >>>= 1;
if (hasMaxDegree) {
px ^= m;
}
curTerm >>>= 1;
}
return summation;
}
}
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