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remove HAS_FAST_INTEGER_VECTORS checks from panama support. #14901

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Merged
rmuir merged 3 commits into from
Jul 11, 2025
Merged

remove HAS_FAST_INTEGER_VECTORS checks from panama support. #14901

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de9c172
remove HAS_FAST_INTEGER_VECTORS checks from panama support.
rmuir Jul 6, 2025
cb30191
rename constants and enable integer vectors when explicit bitsize is …
uschindler Jul 7, 2025
7d5c4b1
nuke dead code
uschindler Jul 8, 2025
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10 changes: 2 additions & 8 deletions ...nfra/src/main/java/org/apache/lucene/gradle/plugins/java/TestsAndRandomizationPlugin.java
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Original file line number Diff line number Diff line change
Expand Up @@ -543,20 +543,14 @@ private static boolean addVectorizationOptions(
Provider<Boolean> defaultVectorizationOption =
buildOptions.addBooleanOption(
"tests.defaultvectorization",
"Uses defaults for running tests with correct JVM settings to test Panama vectorization (tests.jvmargs, tests.vectorsize, tests.forceintegervectors).",
"Uses defaults for running tests with correct JVM settings to test Panama vectorization (tests.jvmargs, tests.vectorsize).",
false);
buildOptions.addOption(
"tests.vectorsize",
"Sets preferred vector size in bits.",
project.provider(() -> defaultVectorizationOption.get() ? "default" : randomVectorSize));

buildOptions.addBooleanOption(
"tests.forceintegervectors",
"Forces use of integer vectors even when slow.",
project.provider(
() -> defaultVectorizationOption.get() ? false : (randomVectorSize != "default")));

optionsInheritedAsProperties.addAll(List.of("tests.vectorsize", "tests.forceintegervectors"));
optionsInheritedAsProperties.add("tests.vectorsize");

return defaultVectorizationOption.get();
}
Expand Down
15 changes: 2 additions & 13 deletions lucene/core/src/java/org/apache/lucene/internal/vectorization/VectorizationProvider.java
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Expand Up @@ -46,7 +46,6 @@
public abstract class VectorizationProvider {

static final OptionalInt TESTS_VECTOR_SIZE;
static final boolean TESTS_FORCE_INTEGER_VECTORS;
static final int UPPER_JAVA_FEATURE_VERSION = getUpperJavaFeatureVersion();

static {
Expand All @@ -63,16 +62,6 @@ public abstract class VectorizationProvider {
// ignored
}
TESTS_VECTOR_SIZE = vs;

boolean enforce = false;
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try {
enforce = Boolean.getBoolean("tests.forceintegervectors");
} catch (
@SuppressWarnings("unused")
SecurityException se) {
// ignored
}
TESTS_FORCE_INTEGER_VECTORS = enforce;
}

private static final String UPPER_JAVA_FEATURE_VERSION_SYSPROP =
Expand Down Expand Up @@ -157,9 +146,9 @@ static VectorizationProvider lookup(boolean testMode) {
vectorMod.ifPresent(VectorizationProvider.class.getModule()::addReads);
// check for testMode and otherwise fallback to default if slowness could happen
if (!testMode) {
if (TESTS_VECTOR_SIZE.isPresent() || TESTS_FORCE_INTEGER_VECTORS) {
if (TESTS_VECTOR_SIZE.isPresent()) {
LOG.warning(
"Vector bitsize and/or integer vectors enforcement; using default vectorization provider outside of testMode");
"Vector bitsize enforcement; using default vectorization provider outside of testMode");
return new DefaultVectorizationProvider();
}
if (Constants.IS_CLIENT_VM) {
Expand Down
3 changes: 1 addition & 2 deletions lucene/core/src/java24/org/apache/lucene/internal/vectorization/PanamaVectorConstants.java
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Expand Up @@ -42,8 +42,7 @@ final class PanamaVectorConstants {
// to be fair, they do document this thing only works well with AVX2/AVX3 and Neon
boolean isAMD64withoutAVX2 =
Constants.OS_ARCH.equals("amd64") && PREFERRED_VECTOR_BITSIZE < 256;
HAS_FAST_INTEGER_VECTORS =
VectorizationProvider.TESTS_FORCE_INTEGER_VECTORS || (isAMD64withoutAVX2 == false);
HAS_FAST_INTEGER_VECTORS = isAMD64withoutAVX2 == false;

@uschindler uschindler Jul 7, 2025

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See above and let's do it like that:

HAS_FAST_INTEGER_VECTORS = isAMD64withoutAVX2 == false || TESTS_VECTOR_SIZE.isPresent()

@uschindler uschindler Jul 7, 2025

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In the special test mode I'd like to test our code, although CPU is wrong.

@rmuir rmuir Jul 7, 2025

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if we can better contain this constant we can also give it a better name. The idea is: if you are on x86, you need AVX2 as a minimum baseline for us to support vectors.

@uschindler uschindler Jul 7, 2025

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That's OK. I just want the condition to stay alive here.


PRERERRED_LONG_SPECIES =
VectorSpecies.of(long.class, VectorShape.forBitSize(PREFERRED_VECTOR_BITSIZE));
Expand Down
22 changes: 9 additions & 13 deletions lucene/core/src/java24/org/apache/lucene/internal/vectorization/PanamaVectorUtilSupport.java
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Expand Up @@ -46,7 +46,6 @@
*
* <ul>
* <li>tests.vectorsize (int)
* <li>tests.forceintegervectors (boolean)
* </ul>
*
* Setting these properties will make this code run EXTREMELY slow!
Expand Down Expand Up @@ -313,9 +312,8 @@ public static int dotProduct(MemorySegment a, MemorySegment b) {
int i = 0;
int res = 0;

// only vectorize if we'll at least enter the loop a single time, and we have at least 128-bit
// vectors (256-bit on intel to dodge performance landmines)
if (a.byteSize() >= 16 && PanamaVectorConstants.HAS_FAST_INTEGER_VECTORS) {
// only vectorize if we'll at least enter the loop a single time
if (a.byteSize() >= 16) {
// compute vectorized dot product consistent with VPDPBUSD instruction
if (VECTOR_BITSIZE >= 512) {
i += BYTE_SPECIES.loopBound(a.byteSize());
Expand Down Expand Up @@ -409,7 +407,7 @@ public int int4DotProduct(byte[] a, boolean apacked, byte[] b, boolean bpacked)
} else if (VECTOR_BITSIZE == 256) {
i += ByteVector.SPECIES_128.loopBound(packed.length);
res += dotProductBody256Int4Packed(unpacked, packed, i);
} else if (PanamaVectorConstants.HAS_FAST_INTEGER_VECTORS) {
} else {
i += ByteVector.SPECIES_64.loopBound(packed.length);
res += dotProductBody128Int4Packed(unpacked, packed, i);
}
Expand All @@ -425,7 +423,7 @@ public int int4DotProduct(byte[] a, boolean apacked, byte[] b, boolean bpacked)
} else {
if (VECTOR_BITSIZE >= 512 || VECTOR_BITSIZE == 256) {
return dotProduct(a, b);
} else if (a.length >= 32 && PanamaVectorConstants.HAS_FAST_INTEGER_VECTORS) {
} else if (a.length >= 32) {
i += ByteVector.SPECIES_128.loopBound(a.length);
res += int4DotProductBody128(a, b, i);
}
Expand Down Expand Up @@ -581,9 +579,8 @@ public static float cosine(MemorySegment a, MemorySegment b) {
int norm1 = 0;
int norm2 = 0;

// only vectorize if we'll at least enter the loop a single time, and we have at least 128-bit
// vectors (256-bit on intel to dodge performance landmines)
if (a.byteSize() >= 16 && PanamaVectorConstants.HAS_FAST_INTEGER_VECTORS) {
// only vectorize if we'll at least enter the loop a single time
if (a.byteSize() >= 16) {
final float[] ret;
if (VECTOR_BITSIZE >= 512) {
i += BYTE_SPECIES.loopBound((int) a.byteSize());
Expand Down Expand Up @@ -704,9 +701,8 @@ public static int squareDistance(MemorySegment a, MemorySegment b) {
int i = 0;
int res = 0;

// only vectorize if we'll at least enter the loop a single time, and we have at least 128-bit
// vectors (256-bit on intel to dodge performance landmines)
if (a.byteSize() >= 16 && PanamaVectorConstants.HAS_FAST_INTEGER_VECTORS) {
// only vectorize if we'll at least enter the loop a single time
if (a.byteSize() >= 16) {
if (VECTOR_BITSIZE >= 256) {
i += BYTE_SPECIES.loopBound((int) a.byteSize());
res += squareDistanceBody256(a, b, i);
Expand Down Expand Up @@ -798,7 +794,7 @@ public int findNextGEQ(int[] buffer, int target, int from, int to) {
public long int4BitDotProduct(byte[] q, byte[] d) {
assert q.length == d.length * 4;
// 128 / 8 == 16
if (d.length >= 16 && PanamaVectorConstants.HAS_FAST_INTEGER_VECTORS) {
if (d.length >= 16) {
if (VECTOR_BITSIZE >= 256) {
return int4BitDotProduct256(q, d);
} else if (VECTOR_BITSIZE == 128) {
Expand Down
7 changes: 5 additions & 2 deletions ...core/src/java24/org/apache/lucene/internal/vectorization/PanamaVectorizationProvider.java
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Expand Up @@ -45,6 +45,10 @@ final class PanamaVectorizationProvider extends VectorizationProvider {
"Vector bit size is less than 128: " + PanamaVectorConstants.PREFERRED_VECTOR_BITSIZE);
}

if (PanamaVectorConstants.HAS_FAST_INTEGER_VECTORS == false) {
throw new UnsupportedOperationException("No integer vector support");

@uschindler uschindler Jul 7, 2025

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I'd change this message a bit more verbose as this is logged to enduser in a warning (see VectorizationProvider around line 169).

Maybe "CPU flags do not guarantee fast integer vectors".

}

this.vectorUtilSupport = new PanamaVectorUtilSupport();

var log = Logger.getLogger(getClass().getName());
Expand All @@ -53,8 +57,7 @@ final class PanamaVectorizationProvider extends VectorizationProvider {
Locale.ENGLISH,
"Java vector incubator API enabled; uses preferredBitSize=%d%s%s",
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PanamaVectorConstants.PREFERRED_VECTOR_BITSIZE,
Constants.HAS_FAST_VECTOR_FMA ? "; FMA enabled" : "",
PanamaVectorConstants.HAS_FAST_INTEGER_VECTORS ? "" : "; floating-point vectors only"));
Constants.HAS_FAST_VECTOR_FMA ? "; FMA enabled" : ""));
}

@Override
Expand Down
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