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LZ4: Port LZ4 1.9.x FAST_DEC_LOOP and enable it on x86 and ARM64

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FAST_DEC_LOOP was introduced from LZ4 1.9.0[1]
This change would be introduce 10% on decompress operation
according to LZ4 benchmark result on X86 devices.
Meanwhile, LZ4 with FAST_DEC_LOOP could get improvements on ARM64,
however clang compiler has downgrade if FAST_DEC_LOOP enabled.

So FAST_DEC_LOOP only enabled on X86/X86-64 or ARM64 with GCC build.

LZ4 FAST_DEC_LOOP bug fixes include as well.
1. fixed read-after input in LZ4_decompress_safe() (issue 681)
2. Fix out-of-bound read in LZ4_decompress_fast() (issue 676)

PS2:
1. Move common API to lz4defs.h
2. Add PPC related inline Macro defination.
3. Force inline new static apis.

Here is the test result on ARM64(cortex-A53)
Benchmark via ZRAM:

Test case:
taskset 03 /data/fio --bs=32k --randrepeat=1 --randseed=100 --refill_buffers \
--buffer_compress_percentage=75  --size=700M \
--scramble_buffers=1 --direct=1 --loops=100 --numjobs=1 \
--filename=/data/test/test --name=seq-read --rw=read --stonewall

Patched:
    READ: bw=150MiB/s (157MB/s)
Vanilla:
    READ: bw=135MiB/s (142MB/s)

[1] https://github.com/lz4/lz4/releases/tag/v1.9.0

Signed-off-by: chenxi.mao <chenxi.mao@sony.com>
Signed-off-by: Kazuki Hashimoto <kazukih@tuta.io>
This commit is contained in:
Chenxi Mao 2019-05-17 13:56:24 +08:00 committed by spakkkk
parent 70e706babd
commit 73837ba8d0
4 changed files with 391 additions and 71 deletions
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4
lib/lz4/lz4_compress.c
View File

@ -322,7 +322,7 @@ static FORCE_INLINE int LZ4_compress_generic(
*token = (BYTE)(litLength << ML_BITS);
/* Copy Literals */
LZ4_wildCopy(op, anchor, op + litLength);
LZ4_wildCopy8(op, anchor, op + litLength);
op += litLength;
}
@ -628,7 +628,7 @@ static int LZ4_compress_destSize_generic(
*token = (BYTE)(litLength << ML_BITS);
/* Copy Literals */
LZ4_wildCopy(op, anchor, op + litLength);
LZ4_wildCopy8(op, anchor, op + litLength);
op += litLength;
}

396
lib/lz4/lz4_decompress.c
View File

@ -50,6 +50,96 @@
#define assert(condition) ((void)0)
#endif
#ifndef LZ4_FAST_DEC_LOOP
#if defined(__i386__) || defined(__x86_64__)
#define LZ4_FAST_DEC_LOOP 1
#elif defined(__aarch64__) && !defined(__clang__)
/* On aarch64, we disable this optimization for clang because on certain
* mobile chipsets and clang, it reduces performance. For more information
* refer to https://github.com/lz4/lz4/pull/707. */
#define LZ4_FAST_DEC_LOOP 1
#else
#define LZ4_FAST_DEC_LOOP 0
#endif
#endif
#if LZ4_FAST_DEC_LOOP
#define FASTLOOP_SAFE_DISTANCE 64
FORCE_O2_INLINE_GCC_PPC64LE void
LZ4_memcpy_using_offset_base(BYTE * dstPtr, const BYTE * srcPtr, BYTE * dstEnd,
const size_t offset)
{
if (offset < 8) {
dstPtr[0] = srcPtr[0];
dstPtr[1] = srcPtr[1];
dstPtr[2] = srcPtr[2];
dstPtr[3] = srcPtr[3];
srcPtr += inc32table[offset];
memcpy(dstPtr + 4, srcPtr, 4);
srcPtr -= dec64table[offset];
dstPtr += 8;
} else {
memcpy(dstPtr, srcPtr, 8);
dstPtr += 8;
srcPtr += 8;
}
LZ4_wildCopy8(dstPtr, srcPtr, dstEnd);
}
/* customized variant of memcpy, which can overwrite up to 32 bytes beyond dstEnd
* this version copies two times 16 bytes (instead of one time 32 bytes)
* because it must be compatible with offsets >= 16. */
FORCE_O2_INLINE_GCC_PPC64LE void
LZ4_wildCopy32(void *dstPtr, const void *srcPtr, void *dstEnd)
{
BYTE *d = (BYTE *) dstPtr;
const BYTE *s = (const BYTE *)srcPtr;
BYTE *const e = (BYTE *) dstEnd;
do {
memcpy(d, s, 16);
memcpy(d + 16, s + 16, 16);
d += 32;
s += 32;
} while (d < e);
}
FORCE_O2_INLINE_GCC_PPC64LE void
LZ4_memcpy_using_offset(BYTE *dstPtr, const BYTE *srcPtr, BYTE *dstEnd,
const size_t offset)
{
BYTE v[8];
switch (offset) {
case 1:
memset(v, *srcPtr, 8);
goto copy_loop;
case 2:
memcpy(v, srcPtr, 2);
memcpy(&v[2], srcPtr, 2);
memcpy(&v[4], &v[0], 4);
goto copy_loop;
case 4:
memcpy(v, srcPtr, 4);
memcpy(&v[4], srcPtr, 4);
goto copy_loop;
default:
LZ4_memcpy_using_offset_base(dstPtr, srcPtr, dstEnd, offset);
return;
}
copy_loop:
memcpy(dstPtr, v, 8);
dstPtr += 8;
while (dstPtr < dstEnd) {
memcpy(dstPtr, v, 8);
dstPtr += 8;
}
}
#endif
/*
* LZ4_decompress_generic() :
* This generic decompression function covers all use cases.
@ -80,25 +170,27 @@ static FORCE_INLINE int LZ4_decompress_generic(
const size_t dictSize
)
{
const BYTE *ip = (const BYTE *) src;
const BYTE * const iend = ip + srcSize;
const BYTE *ip = (const BYTE *)src;
const BYTE *const iend = ip + srcSize;
BYTE *op = (BYTE *) dst;
BYTE * const oend = op + outputSize;
BYTE *const oend = op + outputSize;
BYTE *cpy;
const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4};
static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3};
const int safeDecode = (endOnInput == endOnInputSize);
const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
/* Set up the "end" pointers for the shortcut. */
const BYTE *const shortiend = iend -
(endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/;
(endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/;
const BYTE *const shortoend = oend -
(endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/;
(endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/;
const BYTE *match;
size_t offset;
unsigned int token;
size_t length;
DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__,
srcSize, outputSize);
@ -117,15 +209,195 @@ static FORCE_INLINE int LZ4_decompress_generic(
if ((endOnInput) && unlikely(srcSize == 0))
return -1;
#if LZ4_FAST_DEC_LOOP
if ((oend - op) < FASTLOOP_SAFE_DISTANCE) {
DEBUGLOG(6, "skip fast decode loop");
goto safe_decode;
}
/* Fast loop : decode sequences as long as output < iend-FASTLOOP_SAFE_DISTANCE */
while (1) {
/* Main fastloop assertion: We can always wildcopy FASTLOOP_SAFE_DISTANCE */
assert(oend - op >= FASTLOOP_SAFE_DISTANCE);
if (endOnInput) {
assert(ip < iend);
}
token = *ip++;
length = token >> ML_BITS; /* literal length */
assert(!endOnInput || ip <= iend); /* ip < iend before the increment */
/* decode literal length */
if (length == RUN_MASK) {
variable_length_error error = ok;
length +=
read_variable_length(&ip, iend - RUN_MASK,
endOnInput, endOnInput,
&error);
if (error == initial_error) {
goto _output_error;
}
if ((safeDecode)
&& unlikely((uptrval) (op) + length <
(uptrval) (op))) {
goto _output_error;
} /* overflow detection */
if ((safeDecode)
&& unlikely((uptrval) (ip) + length <
(uptrval) (ip))) {
goto _output_error;
}
/* overflow detection */
/* copy literals */
cpy = op + length;
LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
if (endOnInput) { /* LZ4_decompress_safe() */
if ((cpy > oend - 32)
|| (ip + length > iend - 32)) {
goto safe_literal_copy;
}
LZ4_wildCopy32(op, ip, cpy);
} else { /* LZ4_decompress_fast() */
if (cpy > oend - 8) {
goto safe_literal_copy;
}
LZ4_wildCopy8(op, ip, cpy);
/* LZ4_decompress_fast() cannot copy more than 8 bytes at a time */
/* it doesn't know input length, and only relies on end-of-block */
/* properties */
}
ip += length;
op = cpy;
} else {
cpy = op + length;
if (endOnInput) { /* LZ4_decompress_safe() */
DEBUGLOG(7,
"copy %u bytes in a 16-bytes stripe",
(unsigned)length);
/* We don't need to check oend */
/* since we check it once for each loop below */
if (ip > iend - (16 + 1)) { /*max lit + offset + nextToken */
goto safe_literal_copy;
}
/* Literals can only be 14, but hope compilers optimize */
/*if we copy by a register size */
memcpy(op, ip, 16);
} else {
/* LZ4_decompress_fast() cannot copy more than 8 bytes at a time */
/* it doesn't know input length, and relies on end-of-block */
/* properties */
memcpy(op, ip, 8);
if (length > 8) {
memcpy(op + 8, ip + 8, 8);
}
}
ip += length;
op = cpy;
}
/* get offset */
offset = LZ4_readLE16(ip);
ip += 2; /* end-of-block condition violated */
match = op - offset;
/* get matchlength */
length = token & ML_MASK;
if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) {
goto _output_error;
}
/* Error : offset outside buffers */
if (length == ML_MASK) {
variable_length_error error = ok;
length +=
read_variable_length(&ip, iend - LASTLITERALS + 1,
endOnInput, 0, &error);
if (error != ok) {
goto _output_error;
}
if ((safeDecode)
&& unlikely((uptrval) (op) + length < (uptrval) op)) {
goto _output_error;
} /* overflow detection */
length += MINMATCH;
if (op + length >= oend - FASTLOOP_SAFE_DISTANCE) {
goto safe_match_copy;
}
} else {
length += MINMATCH;
if (op + length >= oend - FASTLOOP_SAFE_DISTANCE) {
goto safe_match_copy;
}
/* Fastpath check: Avoids a branch in LZ4_wildCopy32 if true */
if (!(dict == usingExtDict) || (match >= lowPrefix)) {
if (offset >= 8) {
memcpy(op, match, 8);
memcpy(op + 8, match + 8, 8);
memcpy(op + 16, match + 16, 2);
op += length;
continue;
}
}
}
/* match starting within external dictionary */
if ((dict == usingExtDict) && (match < lowPrefix)) {
if (unlikely(op + length > oend - LASTLITERALS)) {
if (partialDecoding) {
/* reach end of buffer */
length =
min(length, (size_t) (oend - op));
} else {
/* end-of-block condition violated */
goto _output_error;
}
}
if (length <= (size_t) (lowPrefix - match)) {
/* match fits entirely within external dictionary : just copy */
memmove(op, dictEnd - (lowPrefix - match),
length);
op += length;
} else {
/* match stretches into both external dict and current block */
size_t const copySize =
(size_t) (lowPrefix - match);
size_t const restSize = length - copySize;
memcpy(op, dictEnd - copySize, copySize);
op += copySize;
if (restSize > (size_t) (op - lowPrefix)) { /* overlap copy */
BYTE *const endOfMatch = op + restSize;
const BYTE *copyFrom = lowPrefix;
while (op < endOfMatch) {
*op++ = *copyFrom++;
}
} else {
memcpy(op, lowPrefix, restSize);
op += restSize;
}
}
continue;
}
/* copy match within block */
cpy = op + length;
assert((op <= oend) && (oend - op >= 32));
if (unlikely(offset < 16)) {
LZ4_memcpy_using_offset(op, match, cpy, offset);
} else {
LZ4_wildCopy32(op, match, cpy);
}
op = cpy; /* wildcopy correction */
}
safe_decode:
#endif
/* Main Loop : decode sequences */
while (1) {
size_t length;
const BYTE *match;
size_t offset;
/* get literal length */
unsigned int const token = *ip++;
length = token>>ML_BITS;
length = token >> ML_BITS;
/* ip < iend before the increment */
assert(!endOnInput || ip <= iend);
@ -146,26 +418,27 @@ static FORCE_INLINE int LZ4_decompress_generic(
* some compilers can produce better parallelized runtime code
*/
if ((endOnInput ? length != RUN_MASK : length <= 8)
/*
* strictly "less than" on input, to re-enter
* the loop with at least one byte
*/
&& likely((endOnInput ? ip < shortiend : 1) &
(op <= shortoend))) {
/*
* strictly "less than" on input, to re-enter
* the loop with at least one byte
*/
&& likely((endOnInput ? ip < shortiend : 1) &
(op <= shortoend))) {
/* Copy the literals */
LZ4_memcpy(op, ip, endOnInput ? 16 : 8);
op += length; ip += length;
op += length;
ip += length;
/*
* The second stage:
* prepare for match copying, decode full info.
* If it doesn't work out, the info won't be wasted.
*/
length = token & ML_MASK; /* match length */
length = token & ML_MASK; /* match length */
offset = LZ4_readLE16(ip);
ip += 2;
match = op - offset;
assert(match <= op); /* check overflow */
assert(match <= op); /* check overflow */
/* Do not deal with overlapping matches. */
if ((length != ML_MASK) &&
@ -190,28 +463,24 @@ static FORCE_INLINE int LZ4_decompress_generic(
/* decode literal length */
if (length == RUN_MASK) {
unsigned int s;
if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) {
/* overflow detection */
variable_length_error error = ok;
length +=
read_variable_length(&ip, iend - RUN_MASK,
endOnInput, endOnInput,
&error);
if (error == initial_error)
goto _output_error;
}
do {
s = *ip++;
length += s;
} while (likely(endOnInput
? ip < iend - RUN_MASK
: 1) & (s == 255));
if ((safeDecode)
&& unlikely((uptrval)(op) +
length < (uptrval)(op))) {
&& unlikely((uptrval) (op) +
length < (uptrval) (op))) {
/* overflow detection */
goto _output_error;
}
if ((safeDecode)
&& unlikely((uptrval)(ip) +
length < (uptrval)(ip))) {
&& unlikely((uptrval) (ip) +
length < (uptrval) (ip))) {
/* overflow detection */
goto _output_error;
}
@ -219,11 +488,15 @@ static FORCE_INLINE int LZ4_decompress_generic(
/* copy literals */
cpy = op + length;
#if LZ4_FAST_DEC_LOOP
safe_literal_copy:
#endif
LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
if (((endOnInput) && ((cpy > oend - MFLIMIT)
|| (ip + length > iend - (2 + 1 + LASTLITERALS))))
|| ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
|| (ip + length >
iend - (2 + 1 + LASTLITERALS))))
|| ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
if (partialDecoding) {
if (cpy > oend) {
/*
@ -234,7 +507,7 @@ static FORCE_INLINE int LZ4_decompress_generic(
length = oend - op;
}
if ((endOnInput)
&& (ip + length > iend)) {
&& (ip + length > iend)) {
/*
* Error :
* read attempt beyond
@ -244,7 +517,7 @@ static FORCE_INLINE int LZ4_decompress_generic(
}
} else {
if ((!endOnInput)
&& (cpy != oend)) {
&& (cpy != oend)) {
/*
* Error :
* block decoding must
@ -253,7 +526,7 @@ static FORCE_INLINE int LZ4_decompress_generic(
goto _output_error;
}
if ((endOnInput)
&& ((ip + length != iend)
&& ((ip + length != iend)
|| (cpy > oend))) {
/*
* Error :
@ -276,7 +549,7 @@ static FORCE_INLINE int LZ4_decompress_generic(
break;
} else {
/* may overwrite up to WILDCOPYLENGTH beyond cpy */
LZ4_wildCopy(op, ip, cpy);
LZ4_wildCopy8(op, ip, cpy);
ip += length;
op = cpy;
}
@ -295,29 +568,14 @@ _copy_match:
goto _output_error;
}
/* costs ~1%; silence an msan warning when offset == 0 */
/*
* note : when partialDecoding, there is no guarantee that
* at least 4 bytes remain available in output buffer
*/
if (!partialDecoding) {
assert(oend > op);
assert(oend - op >= 4);
LZ4_write32(op, (U32)offset);
}
if (length == ML_MASK) {
unsigned int s;
do {
s = *ip++;
if ((endOnInput) && (ip > iend - LASTLITERALS))
goto _output_error;
length += s;
} while (s == 255);
variable_length_error error = ok;
length +=
read_variable_length(&ip, iend - LASTLITERALS + 1,
endOnInput, 0, &error);
if (error != ok)
goto _output_error;
if ((safeDecode)
&& unlikely(
@ -329,6 +587,10 @@ _copy_match:
length += MINMATCH;
#if LZ4_FAST_DEC_LOOP
safe_match_copy:
#endif
/* match starting within external dictionary */
if ((dict == usingExtDict) && (match < lowPrefix)) {
if (unlikely(op + length > oend - LASTLITERALS)) {
@ -425,7 +687,7 @@ _copy_match:
}
if (op < oCopyLimit) {
LZ4_wildCopy(op, match, oCopyLimit);
LZ4_wildCopy8(op, match, oCopyLimit);
match += oCopyLimit - op;
op = oCopyLimit;
}
@ -434,7 +696,7 @@ _copy_match:
} else {
LZ4_copy8(op, match);
if (length > 16)
LZ4_wildCopy(op + 8, match + 8, cpy);
LZ4_wildCopy8(op + 8, match + 8, cpy);
}
op = cpy; /* wildcopy correction */
}

60
lib/lz4/lz4defs.h
View File

@ -40,6 +40,28 @@
#define FORCE_INLINE __always_inline
/* LZ4_FORCE_O2_GCC_PPC64LE and LZ4_FORCE_O2_INLINE_GCC_PPC64LE
* gcc on ppc64le generates an unrolled SIMDized loop for LZ4_wildCopy8,
* together with a simple 8-byte copy loop as a fall-back path.
* However, this optimization hurts the decompression speed by >30%,
* because the execution does not go to the optimized loop
* for typical compressible data, and all of the preamble checks
* before going to the fall-back path become useless overhead.
* This optimization happens only with the -O3 flag, and -O2 generates
* a simple 8-byte copy loop.
* With gcc on ppc64le, all of the LZ4_decompress_* and LZ4_wildCopy8
* functions are annotated with __attribute__((optimize("O2"))),
* and also LZ4_wildCopy8 is forcibly inlined, so that the O2 attribute
* of LZ4_wildCopy8 does not affect the compression speed.
*/
#if defined(__PPC64__) && defined(__LITTLE_ENDIAN__) && defined(__GNUC__) && !defined(__clang__)
# define FORCE_O2_GCC_PPC64LE __attribute__((optimize("O2")))
# define FORCE_O2_INLINE_GCC_PPC64LE (__attribute__((optimize("O2"))) FORCE_INLINE)
#else
# define FORCE_O2_GCC_PPC64LE FORCE_INLINE
# define FORCE_O2_INLINE_GCC_PPC64LE FORCE_INLINE
#endif
/*-************************************
* Basic Types
**************************************/
@ -99,6 +121,9 @@ typedef uintptr_t uptrval;
#define RUN_BITS (8 - ML_BITS)
#define RUN_MASK ((1U << RUN_BITS) - 1)
static const unsigned inc32table[8] = { 0, 1, 2, 1, 0, 4, 4, 4 };
static const int dec64table[8] = { 0, 0, 0, -1, -4, 1, 2, 3 };
/*-************************************
* Reading and writing into memory
**************************************/
@ -167,7 +192,7 @@ static FORCE_INLINE void LZ4_copy8(void *dst, const void *src)
* customized variant of memcpy,
* which can overwrite up to 7 bytes beyond dstEnd
*/
static FORCE_INLINE void LZ4_wildCopy(void *dstPtr,
static FORCE_O2_INLINE_GCC_PPC64LE void LZ4_wildCopy8(void *dstPtr,
const void *srcPtr, void *dstEnd)
{
BYTE *d = (BYTE *)dstPtr;
@ -231,6 +256,39 @@ static FORCE_INLINE unsigned int LZ4_count(
return (unsigned int)(pIn - pStart);
}
/* Read the variable-length literal or match length.
*
* ip - pointer to use as input.
* lencheck - end ip. Return an error if ip advances >= lencheck.
* loop_check - check ip >= lencheck in body of loop. Returns loop_error if so.
* initial_check - check ip >= lencheck before start of loop. Returns initial_error if so.
* error (output) - error code. Should be set to 0 before call.
*/
typedef enum { loop_error = -2, initial_error = -1, ok = 0} variable_length_error;
static FORCE_INLINE unsigned read_variable_length(const BYTE **ip,
const BYTE *lencheck,
int loop_check, int initial_check,
variable_length_error *error)
{
unsigned length = 0;
unsigned s;
if (initial_check && unlikely((*ip) >= lencheck)) { /* overflow detection */
*error = initial_error;
return length;
}
do {
s = **ip;
(*ip)++;
length += s;
if (loop_check && unlikely((*ip) >= lencheck)) { /* overflow detection */
*error = loop_error;
return length;
}
} while (s == 255);
return length;
}
typedef enum { noLimit = 0, limitedOutput = 1 } limitedOutput_directive;
typedef enum { byPtr, byU32, byU16 } tableType_t;

2
lib/lz4/lz4hc_compress.c
View File

@ -293,7 +293,7 @@ static FORCE_INLINE int LZ4HC_encodeSequence(
*token = (BYTE)(length<<ML_BITS);
/* Copy Literals */
LZ4_wildCopy(*op, *anchor, (*op) + length);
LZ4_wildCopy8(*op, *anchor, (*op) + length);
*op += length;
/* Encode Offset */