SERVER-23506 Vectorized fts char scan for ppc64le

Acceleration via ppc64le altivec support for full text search

3 files changed, 164 insertions, 0 deletions

diff --git a/src/mongo/db/fts/unicode/byte_vector.h b/src/mongo/db/fts/unicode/byte_vector.h
index d361a857ff1..2404e15dfda 100644
--- a/src/mongo/db/fts/unicode/byte_vector.h
+++ b/src/mongo/db/fts/unicode/byte_vector.h
@@ -33,6 +33,8 @@
 // TODO replace this with #if BOOST_HW_SIMD_X86 >= BOOST_HW_SIMD_X86_SSE2_VERSION in boost 1.60
 #if defined(_M_AMD64) || defined(__amd64__)
 #include "mongo/db/fts/unicode/byte_vector_sse2.h"
+#elif defined(__powerpc64__)
+#include "mongo/db/fts/unicode/byte_vector_altivec.h"
 #else  // Other platforms go above here.
 #undef MONGO_HAVE_FAST_BYTE_VECTOR
 #endif
diff --git a/src/mongo/db/fts/unicode/byte_vector_altivec.h b/src/mongo/db/fts/unicode/byte_vector_altivec.h
new file mode 100644
index 00000000000..f7a07ac0743
--- /dev/null
+++ b/src/mongo/db/fts/unicode/byte_vector_altivec.h
@@ -0,0 +1,160 @@
+/**
+ *    Copyright (C) 2016 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include <altivec.h>
+#undef vector
+#undef bool
+
+#include <cstdint>
+
+#include "mongo/platform/bits.h"
+
+namespace mongo {
+namespace unicode {
+
+/**
+ * A sequence of bytes that can be manipulated using vectorized instructions.
+ *
+ * This is specific to the use case in mongo::unicode::String and not intended as a general purpose
+ * vector class.
+ *
+ * This specialization offers acceleration for ppc64le
+ */
+class ByteVector {
+public:
+    using Native = __vector signed char;
+
+    // Logically 16 bits, but this is the actual output type of vec_vbpermq
+    using Mask = uint64_t;
+
+    using Scalar = int8_t;
+    static const int size = sizeof(Native);
+
+    /**
+     * Sets all bytes to 0.
+     */
+    ByteVector() {
+        _data = vec_splat_s8(0);
+    }
+
+    /**
+     * Sets all bytes to val.
+     */
+    explicit ByteVector(Scalar val) {
+        _data = vec_splats(val);
+    }
+
+    /**
+     * Load a vector from a potentially unaligned location.
+     */
+    static ByteVector load(const void* ptr) {
+        // This function is documented as taking an unaligned pointer.
+        return vec_vsx_ld(0, reinterpret_cast<const Native*>(ptr));
+    }
+
+    /**
+     * Store this vector to a potentially unaligned location.
+     */
+    void store(void* ptr) const {
+        // This function is documented as taking an unaligned pointer.
+        vec_vsx_st(_data, 0, reinterpret_cast<Native*>(ptr));
+    }
+
+    /**
+     * Returns a bitmask with the high bit from each byte.
+     */
+    Mask maskHigh() const {
+        // The bits array represents the api indexes of the left to right high bits.
+        //
+        // This seems really wrong, but the indexes you hand to vec_vbpermq are actually mirrored on
+        // little endian (the interface seems more designed for big endian).  You'd do 7, 15, etc on
+        // big endian by comparison.
+        const Native bits = {120, 112, 104, 96, 88, 80, 72, 64, 56, 48, 40, 32, 24, 16, 8, 0};
+
+        return vec_extract(vec_vbpermq(_data, bits), 0);
+    }
+
+    /**
+     * Returns a bitmask with any bit from each byte.
+     *
+     * This operation only makes sense if all bytes are either 0x00 or 0xff, such as the result from
+     * comparison operations.
+     */
+    Mask maskAny() const {
+        return maskHigh();  // Other archs may be more efficient here.
+    }
+
+    /**
+     * Counts zero bits in mask from whichever side corresponds to the lowest memory address.
+     */
+    static uint32_t countInitialZeros(Mask mask) {
+        return mask == 0 ? size : countTrailingZeros64(mask);
+    }
+
+    /**
+     * Sets each byte to 0xff if it is ==(EQ), <(LT), or >(GT), otherwise 0x00.
+     *
+     * May use either signed or unsigned comparisons since this use case doesn't care about bytes
+     * with high bit set.
+     */
+    ByteVector compareEQ(Scalar val) const {
+        return (Native)vec_cmpeq(_data, ByteVector(val)._data);
+    }
+    ByteVector compareLT(Scalar val) const {
+        return (Native)vec_cmplt(_data, ByteVector(val)._data);
+    }
+    ByteVector compareGT(Scalar val) const {
+        return (Native)vec_cmpgt(_data, ByteVector(val)._data);
+    }
+
+    ByteVector operator|(ByteVector other) const {
+        return (Native)vec_or(_data, other._data);
+    }
+
+    ByteVector& operator|=(ByteVector other) {
+        return (*this = (*this | other));
+    }
+
+    ByteVector operator&(ByteVector other) const {
+        return (Native)vec_and(_data, other._data);
+    }
+
+    ByteVector& operator&=(ByteVector other) {
+        return (*this = (*this & other));
+    }
+
+private:
+    ByteVector(Native data) : _data(data) {}
+
+    Native _data;
+};
+
+}  // namespace unicode
+}  // namespace mongo
diff --git a/src/mongo/db/fts/unicode/byte_vector_sse2.h b/src/mongo/db/fts/unicode/byte_vector_sse2.h
index 6262488085a..7a44dd31e92 100644
--- a/src/mongo/db/fts/unicode/byte_vector_sse2.h
+++ b/src/mongo/db/fts/unicode/byte_vector_sse2.h
@@ -41,6 +41,8 @@ namespace unicode {
  *
  * This is specific to the use case in mongo::unicode::String and not intended as a general purpose
  * vector class.
+ *
+ * This specialization offers acceleration for x86_64
  */
 class ByteVector {
 public: