From c53c70a90fdce3e7a53a0412abf7cc2b2a645988 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Thu, 1 Aug 2013 15:52:17 -0400 Subject: [PATCH] tile: optimize and clean up string functions This change cleans up the string code in a number of ways: - For memcpy(), fix bug in prefetch and increase distance to 3 lines; optimize for unaligned data; do all loads before wh64 to make memcpy safe for forward-overlapping calls; etc. Performance is improved. - Use new copy_byte() function on tilegx to spread a single byte value out into a full word using the shufflebytes instruction. - Clean up header include ordering to be more canonical, and remove spurious #undefs of function names. Signed-off-by: Chris Metcalf --- arch/tile/lib/memchr_64.c | 2 +- arch/tile/lib/memcpy_64.c | 255 +++++++++++++++++++++++++--------- arch/tile/lib/memset_32.c | 5 +- arch/tile/lib/memset_64.c | 9 +- arch/tile/lib/strchr_32.c | 2 - arch/tile/lib/strchr_64.c | 2 +- arch/tile/lib/string-endian.h | 13 +- arch/tile/lib/strlen_32.c | 2 - 8 files changed, 209 insertions(+), 81 deletions(-) diff --git a/arch/tile/lib/memchr_64.c b/arch/tile/lib/memchr_64.c index 6f867dbf7c56..f8196b3a950e 100644 --- a/arch/tile/lib/memchr_64.c +++ b/arch/tile/lib/memchr_64.c @@ -36,7 +36,7 @@ void *memchr(const void *s, int c, size_t n) p = (const uint64_t *)(s_int & -8); /* Create eight copies of the byte for which we are looking. */ - goal = 0x0101010101010101ULL * (uint8_t) c; + goal = copy_byte(c); /* Read the first word, but munge it so that bytes before the array * will not match goal. diff --git a/arch/tile/lib/memcpy_64.c b/arch/tile/lib/memcpy_64.c index c79b8e7c6828..46fc1600c17d 100644 --- a/arch/tile/lib/memcpy_64.c +++ b/arch/tile/lib/memcpy_64.c @@ -18,14 +18,17 @@ /* EXPORT_SYMBOL() is in arch/tile/lib/exports.c since this should be asm. */ /* Must be 8 bytes in size. */ -#define word_t uint64_t +#define op_t uint64_t -#if CHIP_L2_LINE_SIZE() != 64 && CHIP_L2_LINE_SIZE() != 128 -#error "Assumes 64 or 128 byte line size" +/* Threshold value for when to enter the unrolled loops. */ +#define OP_T_THRES 16 + +#if CHIP_L2_LINE_SIZE() != 64 +#error "Assumes 64 byte line size" #endif /* How many cache lines ahead should we prefetch? */ -#define PREFETCH_LINES_AHEAD 3 +#define PREFETCH_LINES_AHEAD 4 /* * Provide "base versions" of load and store for the normal code path. @@ -58,8 +61,8 @@ int USERCOPY_FUNC(void *__restrict dstv, const void *__restrict srcv, size_t n) const char *__restrict src1 = (const char *)srcv; const char *__restrict src1_end; const char *__restrict prefetch; - word_t *__restrict dst8; /* 8-byte pointer to destination memory. */ - word_t final; /* Final bytes to write to trailing word, if any */ + op_t *__restrict dst8; /* 8-byte pointer to destination memory. */ + op_t final; /* Final bytes to write to trailing word, if any */ long i; if (n < 16) { @@ -79,104 +82,228 @@ int USERCOPY_FUNC(void *__restrict dstv, const void *__restrict srcv, size_t n) for (i = 0; i < PREFETCH_LINES_AHEAD; i++) { __insn_prefetch(prefetch); prefetch += CHIP_L2_LINE_SIZE(); - prefetch = (prefetch > src1_end) ? prefetch : src1; + prefetch = (prefetch < src1_end) ? prefetch : src1; } /* Copy bytes until dst is word-aligned. */ - for (; (uintptr_t)dst1 & (sizeof(word_t) - 1); n--) + for (; (uintptr_t)dst1 & (sizeof(op_t) - 1); n--) ST1(dst1++, LD1(src1++)); /* 8-byte pointer to destination memory. */ - dst8 = (word_t *)dst1; + dst8 = (op_t *)dst1; - if (__builtin_expect((uintptr_t)src1 & (sizeof(word_t) - 1), 0)) { - /* - * Misaligned copy. Copy 8 bytes at a time, but don't - * bother with other fanciness. - * - * TODO: Consider prefetching and using wh64 as well. - */ + if (__builtin_expect((uintptr_t)src1 & (sizeof(op_t) - 1), 0)) { + /* Unaligned copy. */ - /* Create an aligned src8. */ - const word_t *__restrict src8 = - (const word_t *)((uintptr_t)src1 & -sizeof(word_t)); - word_t b; + op_t tmp0 = 0, tmp1 = 0, tmp2, tmp3; + const op_t *src8 = (const op_t *) ((uintptr_t)src1 & + -sizeof(op_t)); + const void *srci = (void *)src1; + int m; - word_t a = LD8(src8++); - for (; n >= sizeof(word_t); n -= sizeof(word_t)) { - b = LD8(src8++); - a = __insn_dblalign(a, b, src1); - ST8(dst8++, a); - a = b; + m = (CHIP_L2_LINE_SIZE() << 2) - + (((uintptr_t)dst8) & ((CHIP_L2_LINE_SIZE() << 2) - 1)); + m = (n < m) ? n : m; + m /= sizeof(op_t); + + /* Copy until 'dst' is cache-line-aligned. */ + n -= (sizeof(op_t) * m); + + switch (m % 4) { + case 0: + if (__builtin_expect(!m, 0)) + goto _M0; + tmp1 = LD8(src8++); + tmp2 = LD8(src8++); + goto _8B3; + case 2: + m += 2; + tmp3 = LD8(src8++); + tmp0 = LD8(src8++); + goto _8B1; + case 3: + m += 1; + tmp2 = LD8(src8++); + tmp3 = LD8(src8++); + goto _8B2; + case 1: + m--; + tmp0 = LD8(src8++); + tmp1 = LD8(src8++); + if (__builtin_expect(!m, 0)) + goto _8B0; + } + + do { + tmp2 = LD8(src8++); + tmp0 = __insn_dblalign(tmp0, tmp1, srci); + ST8(dst8++, tmp0); +_8B3: + tmp3 = LD8(src8++); + tmp1 = __insn_dblalign(tmp1, tmp2, srci); + ST8(dst8++, tmp1); +_8B2: + tmp0 = LD8(src8++); + tmp2 = __insn_dblalign(tmp2, tmp3, srci); + ST8(dst8++, tmp2); +_8B1: + tmp1 = LD8(src8++); + tmp3 = __insn_dblalign(tmp3, tmp0, srci); + ST8(dst8++, tmp3); + m -= 4; + } while (m); + +_8B0: + tmp0 = __insn_dblalign(tmp0, tmp1, srci); + ST8(dst8++, tmp0); + src8--; + +_M0: + if (__builtin_expect(n >= CHIP_L2_LINE_SIZE(), 0)) { + op_t tmp4, tmp5, tmp6, tmp7, tmp8; + + prefetch = ((const char *)src8) + + CHIP_L2_LINE_SIZE() * PREFETCH_LINES_AHEAD; + + for (tmp0 = LD8(src8++); n >= CHIP_L2_LINE_SIZE(); + n -= CHIP_L2_LINE_SIZE()) { + /* Prefetch and advance to next line to + prefetch, but don't go past the end. */ + __insn_prefetch(prefetch); + + /* Make sure prefetch got scheduled + earlier. */ + __asm__ ("" : : : "memory"); + + prefetch += CHIP_L2_LINE_SIZE(); + prefetch = (prefetch < src1_end) ? prefetch : + (const char *) src8; + + tmp1 = LD8(src8++); + tmp2 = LD8(src8++); + tmp3 = LD8(src8++); + tmp4 = LD8(src8++); + tmp5 = LD8(src8++); + tmp6 = LD8(src8++); + tmp7 = LD8(src8++); + tmp8 = LD8(src8++); + + tmp0 = __insn_dblalign(tmp0, tmp1, srci); + tmp1 = __insn_dblalign(tmp1, tmp2, srci); + tmp2 = __insn_dblalign(tmp2, tmp3, srci); + tmp3 = __insn_dblalign(tmp3, tmp4, srci); + tmp4 = __insn_dblalign(tmp4, tmp5, srci); + tmp5 = __insn_dblalign(tmp5, tmp6, srci); + tmp6 = __insn_dblalign(tmp6, tmp7, srci); + tmp7 = __insn_dblalign(tmp7, tmp8, srci); + + __insn_wh64(dst8); + + ST8(dst8++, tmp0); + ST8(dst8++, tmp1); + ST8(dst8++, tmp2); + ST8(dst8++, tmp3); + ST8(dst8++, tmp4); + ST8(dst8++, tmp5); + ST8(dst8++, tmp6); + ST8(dst8++, tmp7); + + tmp0 = tmp8; + } + src8--; + } + + /* Copy the rest 8-byte chunks. */ + if (n >= sizeof(op_t)) { + tmp0 = LD8(src8++); + for (; n >= sizeof(op_t); n -= sizeof(op_t)) { + tmp1 = LD8(src8++); + tmp0 = __insn_dblalign(tmp0, tmp1, srci); + ST8(dst8++, tmp0); + tmp0 = tmp1; + } + src8--; } if (n == 0) return RETVAL; - b = ((const char *)src8 <= src1_end) ? *src8 : 0; + tmp0 = LD8(src8++); + tmp1 = ((const char *)src8 <= src1_end) + ? LD8((op_t *)src8) : 0; + final = __insn_dblalign(tmp0, tmp1, srci); - /* - * Final source bytes to write to trailing partial - * word, if any. - */ - final = __insn_dblalign(a, b, src1); } else { /* Aligned copy. */ - const word_t* __restrict src8 = (const word_t *)src1; + const op_t *__restrict src8 = (const op_t *)src1; /* src8 and dst8 are both word-aligned. */ if (n >= CHIP_L2_LINE_SIZE()) { /* Copy until 'dst' is cache-line-aligned. */ for (; (uintptr_t)dst8 & (CHIP_L2_LINE_SIZE() - 1); - n -= sizeof(word_t)) + n -= sizeof(op_t)) ST8(dst8++, LD8(src8++)); for (; n >= CHIP_L2_LINE_SIZE(); ) { - __insn_wh64(dst8); + op_t tmp0, tmp1, tmp2, tmp3; + op_t tmp4, tmp5, tmp6, tmp7; /* * Prefetch and advance to next line - * to prefetch, but don't go past the end + * to prefetch, but don't go past the + * end. */ __insn_prefetch(prefetch); + + /* Make sure prefetch got scheduled + earlier. */ + __asm__ ("" : : : "memory"); + prefetch += CHIP_L2_LINE_SIZE(); - prefetch = (prefetch > src1_end) ? prefetch : + prefetch = (prefetch < src1_end) ? prefetch : (const char *)src8; /* - * Copy an entire cache line. Manually - * unrolled to avoid idiosyncracies of - * compiler unrolling. + * Do all the loads before wh64. This + * is necessary if [src8, src8+7] and + * [dst8, dst8+7] share the same cache + * line and dst8 <= src8, as can be + * the case when called from memmove, + * or with code tested on x86 whose + * memcpy always works with forward + * copies. */ -#define COPY_WORD(offset) ({ ST8(dst8+offset, LD8(src8+offset)); n -= 8; }) - COPY_WORD(0); - COPY_WORD(1); - COPY_WORD(2); - COPY_WORD(3); - COPY_WORD(4); - COPY_WORD(5); - COPY_WORD(6); - COPY_WORD(7); -#if CHIP_L2_LINE_SIZE() == 128 - COPY_WORD(8); - COPY_WORD(9); - COPY_WORD(10); - COPY_WORD(11); - COPY_WORD(12); - COPY_WORD(13); - COPY_WORD(14); - COPY_WORD(15); -#elif CHIP_L2_LINE_SIZE() != 64 -# error Fix code that assumes particular L2 cache line sizes -#endif + tmp0 = LD8(src8++); + tmp1 = LD8(src8++); + tmp2 = LD8(src8++); + tmp3 = LD8(src8++); + tmp4 = LD8(src8++); + tmp5 = LD8(src8++); + tmp6 = LD8(src8++); + tmp7 = LD8(src8++); - dst8 += CHIP_L2_LINE_SIZE() / sizeof(word_t); - src8 += CHIP_L2_LINE_SIZE() / sizeof(word_t); + /* wh64 and wait for tmp7 load completion. */ + __asm__ ("move %0, %0; wh64 %1\n" + : : "r"(tmp7), "r"(dst8)); + + ST8(dst8++, tmp0); + ST8(dst8++, tmp1); + ST8(dst8++, tmp2); + ST8(dst8++, tmp3); + ST8(dst8++, tmp4); + ST8(dst8++, tmp5); + ST8(dst8++, tmp6); + ST8(dst8++, tmp7); + + n -= CHIP_L2_LINE_SIZE(); } +#if CHIP_L2_LINE_SIZE() != 64 +# error "Fix code that assumes particular L2 cache line size." +#endif } - for (; n >= sizeof(word_t); n -= sizeof(word_t)) + for (; n >= sizeof(op_t); n -= sizeof(op_t)) ST8(dst8++, LD8(src8++)); if (__builtin_expect(n == 0, 1)) diff --git a/arch/tile/lib/memset_32.c b/arch/tile/lib/memset_32.c index 57dbb3a5bff8..9a7837d11f7d 100644 --- a/arch/tile/lib/memset_32.c +++ b/arch/tile/lib/memset_32.c @@ -12,13 +12,10 @@ * more details. */ -#include - #include #include #include - -#undef memset +#include void *memset(void *s, int c, size_t n) { diff --git a/arch/tile/lib/memset_64.c b/arch/tile/lib/memset_64.c index 3873085711d5..03ef69cd73de 100644 --- a/arch/tile/lib/memset_64.c +++ b/arch/tile/lib/memset_64.c @@ -12,13 +12,11 @@ * more details. */ -#include - #include #include #include - -#undef memset +#include +#include "string-endian.h" void *memset(void *s, int c, size_t n) { @@ -70,8 +68,7 @@ void *memset(void *s, int c, size_t n) n64 = n >> 3; /* Tile input byte out to 64 bits. */ - /* KLUDGE */ - v64 = 0x0101010101010101ULL * (uint8_t)c; + v64 = copy_byte(c); /* This must be at least 8 or the following loop doesn't work. */ #define CACHE_LINE_SIZE_IN_DOUBLEWORDS (CHIP_L2_LINE_SIZE() / 8) diff --git a/arch/tile/lib/strchr_32.c b/arch/tile/lib/strchr_32.c index c94e6f7ae7b5..841fe6963019 100644 --- a/arch/tile/lib/strchr_32.c +++ b/arch/tile/lib/strchr_32.c @@ -16,8 +16,6 @@ #include #include -#undef strchr - char *strchr(const char *s, int c) { int z, g; diff --git a/arch/tile/lib/strchr_64.c b/arch/tile/lib/strchr_64.c index f39f9dc422b0..fe6e31c06f8d 100644 --- a/arch/tile/lib/strchr_64.c +++ b/arch/tile/lib/strchr_64.c @@ -26,7 +26,7 @@ char *strchr(const char *s, int c) const uint64_t *p = (const uint64_t *)(s_int & -8); /* Create eight copies of the byte for which we are looking. */ - const uint64_t goal = 0x0101010101010101ULL * (uint8_t) c; + const uint64_t goal = copy_byte(c); /* Read the first aligned word, but force bytes before the string to * match neither zero nor goal (we make sure the high bit of each diff --git a/arch/tile/lib/string-endian.h b/arch/tile/lib/string-endian.h index c0eed7ce69c3..2e49cbfe9371 100644 --- a/arch/tile/lib/string-endian.h +++ b/arch/tile/lib/string-endian.h @@ -1,5 +1,5 @@ /* - * Copyright 2011 Tilera Corporation. All Rights Reserved. + * Copyright 2013 Tilera Corporation. All Rights Reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -31,3 +31,14 @@ #define CFZ(x) __insn_clz(x) #define REVCZ(x) __insn_ctz(x) #endif + +/* + * Create eight copies of the byte in a uint64_t. Byte Shuffle uses + * the bytes of srcB as the index into the dest vector to select a + * byte. With all indices of zero, the first byte is copied into all + * the other bytes. + */ +static inline uint64_t copy_byte(uint8_t byte) +{ + return __insn_shufflebytes(byte, 0, 0); +} diff --git a/arch/tile/lib/strlen_32.c b/arch/tile/lib/strlen_32.c index 4974292a5534..f26f88e11e4a 100644 --- a/arch/tile/lib/strlen_32.c +++ b/arch/tile/lib/strlen_32.c @@ -16,8 +16,6 @@ #include #include -#undef strlen - size_t strlen(const char *s) { /* Get an aligned pointer. */