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Optimize ScanCopyUnescapedString for insitu parsing

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This commit is contained in:
Milo Yip 2016-01-22 18:26:24 +08:00
parent f13caadded
commit a5990f3eea
3 changed files with 120 additions and 8 deletions
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110
include/rapidjson/reader.h
View File

@ -705,6 +705,9 @@ private:
internal::StreamLocalCopy<InputStream> copy(is);
InputStream& s(copy.s);
RAPIDJSON_ASSERT(s.Peek() == '\"');
s.Take(); // Skip '\"'
bool success = false;
if (parseFlags & kParseInsituFlag) {
typename InputStream::Ch *head = s.PutBegin();
@ -743,9 +746,6 @@ private:
#undef Z16
//!@endcond
RAPIDJSON_ASSERT(is.Peek() == '\"');
is.Take(); // Skip '\"'
for (;;) {
// Scan and copy string before "\\\"" or < 0x20. This is an optional optimzation.
if (!(parseFlags & kParseValidateEncodingFlag))
@ -801,13 +801,14 @@ private:
}
#if defined(RAPIDJSON_SSE2) || defined(RAPIDJSON_SSE42)
// StringStream -> StackStream<char>
static RAPIDJSON_FORCEINLINE void ScanCopyUnescapedString(StringStream& is, StackStream<char>& os) {
const char* p = is.src_;
// Scan one by one until alignment (unaligned load may cross page boundary and cause crash)
const char* nextAligned = reinterpret_cast<const char*>((reinterpret_cast<size_t>(p) + 15) & static_cast<size_t>(~15));
while (p != nextAligned)
if (RAPIDJSON_UNLIKELY(*p == '\"') || RAPIDJSON_UNLIKELY(*p == '\\') || RAPIDJSON_UNLIKELY(*p < 0x20)) {
if (RAPIDJSON_UNLIKELY(*p == '\"') || RAPIDJSON_UNLIKELY(*p == '\\') || RAPIDJSON_UNLIKELY(static_cast<unsigned>(*p) < 0x20)) {
is.src_ = p;
return;
}
@ -850,6 +851,107 @@ private:
is.src_ = p;
}
// InsituStringStream -> InsituStringStream
static RAPIDJSON_FORCEINLINE void ScanCopyUnescapedString(InsituStringStream& is, InsituStringStream& os) {
RAPIDJSON_ASSERT(&is == &os);
if (is.src_ == is.dst_) {
SkipUnescapedString(is);
return;
}
char* p = is.src_;
char *q = is.dst_;
// Scan one by one until alignment (unaligned load may cross page boundary and cause crash)
const char* nextAligned = reinterpret_cast<const char*>((reinterpret_cast<size_t>(p) + 15) & static_cast<size_t>(~15));
while (p != nextAligned)
if (RAPIDJSON_UNLIKELY(*p == '\"') || RAPIDJSON_UNLIKELY(*p == '\\') || RAPIDJSON_UNLIKELY(static_cast<unsigned>(*p) < 0x20))
goto exit;
else
*q++ = *p++;
// The rest of string using SIMD
static const char dquote[16] = { '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"' };
static const char bslash[16] = { '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\' };
static const char space[16] = { 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19 };
const __m128i dq = _mm_loadu_si128(reinterpret_cast<const __m128i *>(&dquote[0]));
const __m128i bs = _mm_loadu_si128(reinterpret_cast<const __m128i *>(&bslash[0]));
const __m128i sp = _mm_loadu_si128(reinterpret_cast<const __m128i *>(&space[0]));
for (;; p += 16, q += 16) {
const __m128i s = _mm_load_si128(reinterpret_cast<const __m128i *>(p));
const __m128i t1 = _mm_cmpeq_epi8(s, dq);
const __m128i t2 = _mm_cmpeq_epi8(s, bs);
const __m128i t3 = _mm_cmpeq_epi8(_mm_max_epu8(s, sp), sp); // s < 0x20 <=> max(s, 0x19) == 0x19
const __m128i x = _mm_or_si128(_mm_or_si128(t1, t2), t3);
unsigned short r = static_cast<unsigned short>(_mm_movemask_epi8(x));
if (RAPIDJSON_UNLIKELY(r != 0)) { // some of characters is escaped
size_t length;
#ifdef _MSC_VER // Find the index of first escaped
unsigned long offset;
_BitScanForward(&offset, r);
length = offset;
#else
length = static_cast<size_t>(__builtin_ffs(r) - 1);
#endif
for (const char* pend = p + length; p != pend; )
*q++ = *p++;
break;
}
_mm_storeu_si128(reinterpret_cast<__m128i *>(q), s);
}
exit:
is.src_ = p;
is.dst_ = q;
}
// When read/write pointers are the same for insitu stream, just skip unescaped characters
static RAPIDJSON_FORCEINLINE void SkipUnescapedString(InsituStringStream& is) {
RAPIDJSON_ASSERT(is.src_ == is.dst_);
char* p = is.src_;
// Scan one by one until alignment (unaligned load may cross page boundary and cause crash)
const char* nextAligned = reinterpret_cast<const char*>((reinterpret_cast<size_t>(p) + 15) & static_cast<size_t>(~15));
bool found = false;
for (; p != nextAligned; p++)
if (RAPIDJSON_UNLIKELY(*p == '\"') || RAPIDJSON_UNLIKELY(*p == '\\') || RAPIDJSON_UNLIKELY(static_cast<unsigned>(*p) < 0x20))
goto exit;
// The rest of string using SIMD
static const char dquote[16] = { '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"', '\"' };
static const char bslash[16] = { '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\', '\\' };
static const char space[16] = { 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19 };
const __m128i dq = _mm_loadu_si128(reinterpret_cast<const __m128i *>(&dquote[0]));
const __m128i bs = _mm_loadu_si128(reinterpret_cast<const __m128i *>(&bslash[0]));
const __m128i sp = _mm_loadu_si128(reinterpret_cast<const __m128i *>(&space[0]));
for (;; p += 16) {
const __m128i s = _mm_load_si128(reinterpret_cast<const __m128i *>(p));
const __m128i t1 = _mm_cmpeq_epi8(s, dq);
const __m128i t2 = _mm_cmpeq_epi8(s, bs);
const __m128i t3 = _mm_cmpeq_epi8(_mm_max_epu8(s, sp), sp); // s < 0x20 <=> max(s, 0x19) == 0x19
const __m128i x = _mm_or_si128(_mm_or_si128(t1, t2), t3);
unsigned short r = static_cast<unsigned short>(_mm_movemask_epi8(x));
if (RAPIDJSON_UNLIKELY(r != 0)) { // some of characters is escaped
size_t length;
#ifdef _MSC_VER // Find the index of first escaped
unsigned long offset;
_BitScanForward(&offset, r);
length = offset;
#else
length = static_cast<size_t>(__builtin_ffs(r) - 1);
#endif
p += length;
break;
}
}
exit:
is.src_ = is.dst_ = p;
}
#endif
template<typename InputStream, bool backup>

9
test/perftest/perftest.h
View File

@ -135,11 +135,11 @@ public:
sprintf(filename, "%s/%s", typespaths[i], typesfilenames[j]);
if (FILE* fp = fopen(filename, "rb")) {
fseek(fp, 0, SEEK_END);
size_t length = (size_t)ftell(fp);
typesLength_[j] = (size_t)ftell(fp);
fseek(fp, 0, SEEK_SET);
types_[j] = (char*)malloc(length + 1);
ASSERT_EQ(length, fread(types_[j], 1, length, fp));
types_[j][length] = '\0';
types_[j] = (char*)malloc(typesLength_[j] + 1);
ASSERT_EQ(typesLength_[j], fread(types_[j], 1, typesLength_[j], fp));
types_[j][typesLength_[j]] = '\0';
fclose(fp);
break;
}
@ -170,6 +170,7 @@ protected:
char *whitespace_;
size_t whitespace_length_;
char *types_[7];
size_t typesLength_[7];
static const size_t kTrialCount = 1000;
};

9
test/perftest/rapidjsontest.cpp
View File

@ -103,6 +103,15 @@ TEST_F(RapidJson, SIMD_SUFFIX(ReaderParse_DummyHandler_##Name)) {\
Reader reader;\
EXPECT_TRUE(reader.Parse(s, h));\
}\
}\
TEST_F(RapidJson, SIMD_SUFFIX(ReaderParseInsitu_DummyHandler_##Name)) {\
for (size_t i = 0; i < kTrialCount * 10; i++) {\
memcpy(temp_, types_[index], typesLength_[index] + 1);\
InsituStringStream s(temp_);\
BaseReaderHandler<> h;\
Reader reader;\
EXPECT_TRUE(reader.Parse<kParseInsituFlag>(s, h));\
}\
}
TEST_TYPED(0, Booleans)