File zlib-1.2.12-adler32-vector-optimizations-for-power.patch of Package zlib
From 772f4bd0f880c4c193ab7da78728f38821572a02 Mon Sep 17 00:00:00 2001
From: Rogerio Alves <rcardoso@linux.ibm.com>
Date: Mon, 9 Dec 2019 14:40:53 -0300
Subject: [PATCH] Adler32 vector optimization for Power.
This commit implements a Power (POWER8+) vector optimization for Adler32
checksum using VSX (vector) instructions. The VSX adler32 checksum is up
to 10x fast than the adler32 baseline code.
Author: Rogerio Alves <rcardoso@linux.ibm.com>
---
CMakeLists.txt | 1 +
Makefile.in | 8 ++
adler32.c | 11 ++
configure | 4 +-
contrib/power/adler32_power8.c | 196 +++++++++++++++++++++++++++++++
contrib/power/adler32_resolver.c | 15 +++
contrib/power/power.h | 4 +-
7 files changed, 236 insertions(+), 3 deletions(-)
create mode 100644 contrib/power/adler32_power8.c
create mode 100644 contrib/power/adler32_resolver.c
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 581e1fa6d..c6296ee68 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -185,6 +185,7 @@ if(CMAKE_COMPILER_IS_GNUCC)
if(POWER8)
add_definitions(-DZ_POWER8)
set(ZLIB_POWER8
+ contrib/power/adler32_power8.c
contrib/power/crc32_z_power8.c)
set_source_files_properties(
diff --git a/Makefile.in b/Makefile.in
index 16943044e..a0ffac860 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -165,6 +165,9 @@ minigzip64.o: $(SRCDIR)test/minigzip.c $(SRCDIR)zlib.h zconf.h
adler32.o: $(SRCDIR)adler32.c
$(CC) $(CFLAGS) $(ZINC) -c -o $@ $(SRCDIR)adler32.c
+adler32_power8.o: $(SRCDIR)contrib/power/adler32_power8.c
+ $(CC) $(CFLAGS) -mcpu=power8 $(ZINC) -c -o $@ $(SRCDIR)contrib/power/adler32_power8.c
+
crc32.o: $(SRCDIR)crc32.c
$(CC) $(CFLAGS) $(ZINC) -c -o $@ $(SRCDIR)crc32.c
@@ -216,6 +219,11 @@ adler32.lo: $(SRCDIR)adler32.c
$(CC) $(SFLAGS) $(ZINC) -DPIC -c -o objs/adler32.o $(SRCDIR)adler32.c
-@mv objs/adler32.o $@
+adler32_power8.lo: $(SRCDIR)contrib/power/adler32_power8.c
+ -@mkdir objs 2>/dev/null || test -d objs
+ $(CC) $(SFLAGS) -mcpu=power8 $(ZINC) -DPIC -c -o objs/adler32_power8.o $(SRCDIR)contrib/power/adler32_power8.c
+ -@mv objs/adler32_power8.o $@
+
crc32.lo: $(SRCDIR)crc32.c
-@mkdir objs 2>/dev/null || test -d objs
$(CC) $(SFLAGS) $(ZINC) -DPIC -c -o objs/crc32.o $(SRCDIR)crc32.c
diff --git a/adler32.c b/adler32.c
index d0be4380a..4bde0fa18 100644
--- a/adler32.c
+++ b/adler32.c
@@ -131,6 +131,12 @@ uLong ZEXPORT adler32_z(adler, buf, len)
}
/* ========================================================================= */
+
+#ifdef Z_POWER_OPT
+/* Rename the default function to avoid naming conflicts */
+#define adler32 adler32_default
+#endif /* Z_POWER_OPT */
+
uLong ZEXPORT adler32(adler, buf, len)
uLong adler;
const Bytef *buf;
@@ -139,6 +145,11 @@ uLong ZEXPORT adler32(adler, buf, len)
return adler32_z(adler, buf, len);
}
+#ifdef Z_POWER_OPT
+#undef adler32
+#include "contrib/power/adler32_resolver.c"
+#endif /* Z_POWER_OPT */
+
/* ========================================================================= */
local uLong adler32_combine_(adler1, adler2, len2)
uLong adler1;
diff --git a/configure b/configure
index 914d9f4aa..810a7404d 100755
--- a/configure
+++ b/configure
@@ -879,8 +879,8 @@ if tryboth $CC -c $CFLAGS $test.c; then
if tryboth $CC -c $CFLAGS -mcpu=power8 $test.c; then
POWER8="-DZ_POWER8"
- PIC_OBJC="${PIC_OBJC} crc32_z_power8.lo"
- OBJC="${OBJC} crc32_z_power8.o"
+ PIC_OBJC="${PIC_OBJC} adler32_power8.lo crc32_z_power8.lo"
+ OBJC="${OBJC} adler32_power8.o crc32_z_power8.o"
echo "Checking for -mcpu=power8 support... Yes." | tee -a configure.log
else
echo "Checking for -mcpu=power8 support... No." | tee -a configure.log
diff --git a/contrib/power/adler32_power8.c b/contrib/power/adler32_power8.c
new file mode 100644
index 000000000..473c39457
--- /dev/null
+++ b/contrib/power/adler32_power8.c
@@ -0,0 +1,196 @@
+/*
+ * Adler32 for POWER 8+ using VSX instructions.
+ *
+ * Calculate adler32 checksum for 16 bytes at once using POWER8+ VSX (vector)
+ * instructions.
+ *
+ * If adler32 do 1 byte at time on the first iteration s1 is s1_0 (_n means
+ * iteration n) is the initial value of adler - at start _0 is 1 unless
+ * adler initial value is different than 1. So s1_1 = s1_0 + c[0] after
+ * the first calculation. For the iteration s1_2 = s1_1 + c[1] and so on.
+ * Hence, for iteration N, s1_N = s1_(N-1) + c[N] is the value of s1 on
+ * after iteration N.
+ *
+ * Therefore, for s2 and iteration N, s2_N = s2_0 + N*s1_N + N*c[0] +
+ * N-1*c[1] + ... + c[N]
+ *
+ * In a more general way:
+ *
+ * s1_N = s1_0 + sum(i=1 to N)c[i]
+ * s2_N = s2_0 + N*s1 + sum (i=1 to N)(N-i+1)*c[i]
+ *
+ * Where s1_N, s2_N are the values for s1, s2 after N iterations. So if we
+ * can process N-bit at time we can do this at once.
+ *
+ * Since VSX can support 16-bit vector instructions, we can process
+ * 16-bit at time using N = 16 we have:
+ *
+ * s1 = s1_16 = s1_(16-1) + c[16] = s1_0 + sum(i=1 to 16)c[i]
+ * s2 = s2_16 = s2_0 + 16*s1 + sum(i=1 to 16)(16-i+1)*c[i]
+ *
+ * After the first iteration we calculate the adler32 checksum for 16 bytes.
+ *
+ * For more background about adler32 please check the RFC:
+ * https://www.ietf.org/rfc/rfc1950.txt
+ *
+ * Copyright (C) 2019 Rogerio Alves <rcardoso@linux.ibm.com>, IBM
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ *
+ */
+
+#include "../../zutil.h"
+#include <altivec.h>
+
+/* Largest prime smaller than 65536. */
+#define BASE 65521U
+#define NMAX 5552
+/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1. */
+
+#define DO1(s1,s2,buf,i) {(s1) += buf[(i)]; (s2) += (s1);}
+#define DO2(s1,s2,buf,i) {DO1(s1,s2,buf,i); DO1(s1,s2,buf,i+1);}
+#define DO4(s1,s2,buf,i) {DO2(s1,s2,buf,i); DO2(s1,s2,buf,i+2);}
+#define DO8(s1,s2,buf,i) {DO4(s1,s2,buf,i); DO4(s1,s2,buf,i+4);}
+#define DO16(s1,s2,buf) {DO8(s1,s2,buf,0); DO8(s1,s2,buf,8);}
+
+/* Vector across sum unsigned int (saturate). */
+inline vector unsigned int vec_sumsu (vector unsigned int __a,
+ vector unsigned int __b)
+{
+ __b = vec_sld(__a, __a, 8);
+ __b = vec_add(__b, __a);
+ __a = vec_sld(__b, __b, 4);
+ __a = vec_add(__a, __b);
+
+ return __a;
+}
+
+uLong ZLIB_INTERNAL _adler32_power8 (uLong adler, const Bytef* buf, uInt len)
+{
+ /* If buffer is empty or len=0 we need to return adler initial value. */
+ if (buf == NULL)
+ return 1;
+
+ unsigned int s1 = adler & 0xffff;
+ unsigned int s2 = (adler >> 16) & 0xffff;
+
+ /* in case user likes doing a byte at a time, keep it fast */
+ if (len == 1) {
+ s1 += buf[0];
+ if (s1 >= BASE)
+ s1 -= BASE;
+ s2 += s1;
+ if (s2 >= BASE)
+ s2 -= BASE;
+ return (s2 << 16) | s1;
+ }
+
+ /* Keep it fast for short length buffers. */
+ if (len < 16) {
+ while (len--) {
+ s1 += *buf++;
+ s2 += s1;
+ }
+ if (s1 >= BASE)
+ s1 -= BASE;
+ s2 %= BASE;
+ return (s2 << 16) | s1;
+ }
+
+ /* This is faster than VSX code for len < 64. */
+ if (len < 64) {
+ while (len >= 16) {
+ len -= 16;
+ DO16(s1,s2,buf);
+ buf += 16;
+ }
+ } else {
+ /* Use POWER VSX instructions for len >= 64. */
+ const vector unsigned int v_zeros = { 0 };
+ const vector unsigned char v_mul = {16, 15, 14, 13, 12, 11, 10, 9, 8, 7,
+ 6, 5, 4, 3, 2, 1};
+ const vector unsigned char vsh = vec_splat_u8(4);
+ const vector unsigned int vmask = {0xffffffff, 0x0, 0x0, 0x0};
+ vector unsigned int vs1 = vec_xl(0, &s1);
+ vector unsigned int vs2 = vec_xl(0, &s2);
+ vector unsigned int vs1_save = { 0 };
+ vector unsigned int vsum1, vsum2;
+ vector unsigned char vbuf;
+ int n;
+
+ /* Zeros the undefined values of vectors vs1, vs2. */
+ vs1 = vec_and(vs1, vmask);
+ vs2 = vec_and(vs2, vmask);
+
+ /* Do length bigger than NMAX in blocks of NMAX size. */
+ while (len >= NMAX) {
+ len -= NMAX;
+ n = NMAX / 16;
+ do {
+ vbuf = vec_xl(0, (unsigned char *) buf);
+ vsum1 = vec_sum4s(vbuf, v_zeros); /* sum(i=1 to 16) buf[i]. */
+ /* sum(i=1 to 16) buf[i]*(16-i+1). */
+ vsum2 = vec_msum(vbuf, v_mul, v_zeros);
+ /* Save vs1. */
+ vs1_save = vec_add(vs1_save, vs1);
+ /* Accumulate the sums. */
+ vs1 = vec_add(vsum1, vs1);
+ vs2 = vec_add(vsum2, vs2);
+
+ buf += 16;
+ } while (--n);
+ /* Once each block of NMAX size. */
+ vs1 = vec_sumsu(vs1, vsum1);
+ vs1_save = vec_sll(vs1_save, vsh); /* 16*vs1_save. */
+ vs2 = vec_add(vs1_save, vs2);
+ vs2 = vec_sumsu(vs2, vsum2);
+
+ /* vs1[0] = (s1_i + sum(i=1 to 16)buf[i]) mod 65521. */
+ vs1[0] = vs1[0] % BASE;
+ /* vs2[0] = s2_i + 16*s1_save +
+ sum(i=1 to 16)(16-i+1)*buf[i] mod 65521. */
+ vs2[0] = vs2[0] % BASE;
+
+ vs1 = vec_and(vs1, vmask);
+ vs2 = vec_and(vs2, vmask);
+ vs1_save = v_zeros;
+ }
+
+ /* len is less than NMAX one modulo is needed. */
+ if (len >= 16) {
+ while (len >= 16) {
+ len -= 16;
+
+ vbuf = vec_xl(0, (unsigned char *) buf);
+
+ vsum1 = vec_sum4s(vbuf, v_zeros); /* sum(i=1 to 16) buf[i]. */
+ /* sum(i=1 to 16) buf[i]*(16-i+1). */
+ vsum2 = vec_msum(vbuf, v_mul, v_zeros);
+ /* Save vs1. */
+ vs1_save = vec_add(vs1_save, vs1);
+ /* Accumulate the sums. */
+ vs1 = vec_add(vsum1, vs1);
+ vs2 = vec_add(vsum2, vs2);
+
+ buf += 16;
+ }
+ /* Since the size will be always less than NMAX we do this once. */
+ vs1 = vec_sumsu(vs1, vsum1);
+ vs1_save = vec_sll(vs1_save, vsh); /* 16*vs1_save. */
+ vs2 = vec_add(vs1_save, vs2);
+ vs2 = vec_sumsu(vs2, vsum2);
+ }
+ /* Copy result back to s1, s2 (mod 65521). */
+ s1 = vs1[0] % BASE;
+ s2 = vs2[0] % BASE;
+ }
+
+ /* Process tail (len < 16). */
+ while (len--) {
+ s1 += *buf++;
+ s2 += s1;
+ }
+ s1 %= BASE;
+ s2 %= BASE;
+
+ return (s2 << 16) | s1;
+}
diff --git a/contrib/power/adler32_resolver.c b/contrib/power/adler32_resolver.c
new file mode 100644
index 000000000..07a1a2cb2
--- /dev/null
+++ b/contrib/power/adler32_resolver.c
@@ -0,0 +1,15 @@
+/* Copyright (C) 2019 Rogerio Alves <rcardoso@linux.ibm.com>, IBM
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+#include "../gcc/zifunc.h"
+#include "power.h"
+
+Z_IFUNC(adler32) {
+#ifdef Z_POWER8
+ if (__builtin_cpu_supports("arch_2_07"))
+ return _adler32_power8;
+#endif
+
+ return adler32_default;
+}
diff --git a/contrib/power/power.h b/contrib/power/power.h
index 79123aa90..f57c76167 100644
--- a/contrib/power/power.h
+++ b/contrib/power/power.h
@@ -2,7 +2,9 @@
* 2019 Rogerio Alves <rogerio.alves@ibm.com>, IBM
* For conditions of distribution and use, see copyright notice in zlib.h
*/
-
#include "../../zconf.h"
+#include "../../zutil.h"
+
+uLong _adler32_power8(uLong adler, const Bytef* buf, uInt len);
unsigned long _crc32_z_power8(unsigned long, const Bytef *, z_size_t);
