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Micro-optimize fletcher4 calculations

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When processing abds, we execute 1 `kfpu_begin()`/`kfpu_end()` pair on
every page in the abd. This is wasteful and slows down checksum
performance versus what the benchmark claimed. We correct this by moving
those calls to the init and fini functions.

Also, we always check the buffer length against 0 before calling the
non-scalar checksum functions. This means that we do not need to execute
the loop condition for the first loop iteration. That allows us to
micro-optimize the checksum calculations by switching to do-while loops.

Note that we do not apply that micro-optimization to the scalar
implementation because there is no check in
`fletcher_4_incremental_native()`/`fletcher_4_incremental_byteswap()`
against 0 sized buffers being passed.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #14247
This commit is contained in:
Richard Yao 2022-12-05 14:00:34 -05:00 committed by GitHub
parent 7b9a423076
commit 59493b63c1
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
6 changed files with 36 additions and 68 deletions
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18
module/zcommon/zfs_fletcher_aarch64_neon.c
View file

@ -52,6 +52,7 @@ ZFS_NO_SANITIZE_UNDEFINED
static void
fletcher_4_aarch64_neon_init(fletcher_4_ctx_t *ctx)
{
kfpu_begin();
memset(ctx->aarch64_neon, 0, 4 * sizeof (zfs_fletcher_aarch64_neon_t));
}
@ -69,6 +70,7 @@ fletcher_4_aarch64_neon_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp)
8 * ctx->aarch64_neon[3].v[1] - 8 * ctx->aarch64_neon[2].v[1] +
ctx->aarch64_neon[1].v[1];
ZIO_SET_CHECKSUM(zcp, A, B, C, D);
kfpu_end();
}
#define NEON_INIT_LOOP() \
@ -146,17 +148,13 @@ unsigned char TMP2 __attribute__((vector_size(16)));
unsigned char SRC __attribute__((vector_size(16)));
#endif
kfpu_begin();
NEON_INIT_LOOP();
for (; ip < ipend; ip += 2) {
do {
NEON_MAIN_LOOP(NEON_DONT_REVERSE);
}
} while ((ip += 2) < ipend);
NEON_FINI_LOOP();
kfpu_end();
}
static void
@ -185,17 +183,13 @@ unsigned char TMP2 __attribute__((vector_size(16)));
unsigned char SRC __attribute__((vector_size(16)));
#endif
kfpu_begin();
NEON_INIT_LOOP();
for (; ip < ipend; ip += 2) {
do {
NEON_MAIN_LOOP(NEON_DO_REVERSE);
}
} while ((ip += 2) < ipend);
NEON_FINI_LOOP();
kfpu_end();
}
static boolean_t fletcher_4_aarch64_neon_valid(void)

26
module/zcommon/zfs_fletcher_avx512.c
View file

@ -39,6 +39,7 @@ ZFS_NO_SANITIZE_UNDEFINED
static void
fletcher_4_avx512f_init(fletcher_4_ctx_t *ctx)
{
kfpu_begin();
memset(ctx->avx512, 0, 4 * sizeof (zfs_fletcher_avx512_t));
}
@ -72,6 +73,7 @@ fletcher_4_avx512f_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp)
}
ZIO_SET_CHECKSUM(zcp, A, B, C, D);
kfpu_end();
}
#define FLETCHER_4_AVX512_RESTORE_CTX(ctx) \
@ -96,21 +98,17 @@ fletcher_4_avx512f_native(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
const uint32_t *ip = buf;
const uint32_t *ipend = (uint32_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_AVX512_RESTORE_CTX(ctx);
for (; ip < ipend; ip += 8) {
do {
__asm("vpmovzxdq %0, %%zmm4"::"m" (*ip));
__asm("vpaddq %zmm4, %zmm0, %zmm0");
__asm("vpaddq %zmm0, %zmm1, %zmm1");
__asm("vpaddq %zmm1, %zmm2, %zmm2");
__asm("vpaddq %zmm2, %zmm3, %zmm3");
}
} while ((ip += 8) < ipend);
FLETCHER_4_AVX512_SAVE_CTX(ctx);
kfpu_end();
}
STACK_FRAME_NON_STANDARD(fletcher_4_avx512f_native);
@ -122,8 +120,6 @@ fletcher_4_avx512f_byteswap(fletcher_4_ctx_t *ctx, const void *buf,
const uint32_t *ip = buf;
const uint32_t *ipend = (uint32_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_AVX512_RESTORE_CTX(ctx);
__asm("vpbroadcastq %0, %%zmm8" :: "r" (byteswap_mask));
@ -131,7 +127,7 @@ fletcher_4_avx512f_byteswap(fletcher_4_ctx_t *ctx, const void *buf,
__asm("vpsllq $16, %zmm8, %zmm10");
__asm("vpsllq $24, %zmm8, %zmm11");
for (; ip < ipend; ip += 8) {
do {
__asm("vpmovzxdq %0, %%zmm5"::"m" (*ip));
__asm("vpsrlq $24, %zmm5, %zmm6");
@ -150,11 +146,9 @@ fletcher_4_avx512f_byteswap(fletcher_4_ctx_t *ctx, const void *buf,
__asm("vpaddq %zmm0, %zmm1, %zmm1");
__asm("vpaddq %zmm1, %zmm2, %zmm2");
__asm("vpaddq %zmm2, %zmm3, %zmm3");
}
} while ((ip += 8) < ipend);
FLETCHER_4_AVX512_SAVE_CTX(ctx)
kfpu_end();
}
STACK_FRAME_NON_STANDARD(fletcher_4_avx512f_byteswap);
@ -189,13 +183,11 @@ fletcher_4_avx512bw_byteswap(fletcher_4_ctx_t *ctx, const void *buf,
const uint32_t *ip = buf;
const uint32_t *ipend = (uint32_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_AVX512_RESTORE_CTX(ctx);
__asm("vmovdqu64 %0, %%zmm5" :: "m" (mask));
for (; ip < ipend; ip += 8) {
do {
__asm("vpmovzxdq %0, %%zmm4"::"m" (*ip));
__asm("vpshufb %zmm5, %zmm4, %zmm4");
@ -204,11 +196,9 @@ fletcher_4_avx512bw_byteswap(fletcher_4_ctx_t *ctx, const void *buf,
__asm("vpaddq %zmm0, %zmm1, %zmm1");
__asm("vpaddq %zmm1, %zmm2, %zmm2");
__asm("vpaddq %zmm2, %zmm3, %zmm3");
}
} while ((ip += 8) < ipend);
FLETCHER_4_AVX512_SAVE_CTX(ctx)
kfpu_end();
}
STACK_FRAME_NON_STANDARD(fletcher_4_avx512bw_byteswap);

18
module/zcommon/zfs_fletcher_intel.c
View file

@ -51,6 +51,7 @@ ZFS_NO_SANITIZE_UNDEFINED
static void
fletcher_4_avx2_init(fletcher_4_ctx_t *ctx)
{
kfpu_begin();
memset(ctx->avx, 0, 4 * sizeof (zfs_fletcher_avx_t));
}
@ -81,6 +82,7 @@ fletcher_4_avx2_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp)
64 * ctx->avx[3].v[3];
ZIO_SET_CHECKSUM(zcp, A, B, C, D);
kfpu_end();
}
#define FLETCHER_4_AVX2_RESTORE_CTX(ctx) \
@ -106,22 +108,18 @@ fletcher_4_avx2_native(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
const uint64_t *ip = buf;
const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_AVX2_RESTORE_CTX(ctx);
for (; ip < ipend; ip += 2) {
do {
asm volatile("vpmovzxdq %0, %%ymm4"::"m" (*ip));
asm volatile("vpaddq %ymm4, %ymm0, %ymm0");
asm volatile("vpaddq %ymm0, %ymm1, %ymm1");
asm volatile("vpaddq %ymm1, %ymm2, %ymm2");
asm volatile("vpaddq %ymm2, %ymm3, %ymm3");
}
} while ((ip += 2) < ipend);
FLETCHER_4_AVX2_SAVE_CTX(ctx);
asm volatile("vzeroupper");
kfpu_end();
}
static void
@ -134,13 +132,11 @@ fletcher_4_avx2_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
const uint64_t *ip = buf;
const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_AVX2_RESTORE_CTX(ctx);
asm volatile("vmovdqu %0, %%ymm5" :: "m" (mask));
for (; ip < ipend; ip += 2) {
do {
asm volatile("vpmovzxdq %0, %%ymm4"::"m" (*ip));
asm volatile("vpshufb %ymm5, %ymm4, %ymm4");
@ -148,12 +144,10 @@ fletcher_4_avx2_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
asm volatile("vpaddq %ymm0, %ymm1, %ymm1");
asm volatile("vpaddq %ymm1, %ymm2, %ymm2");
asm volatile("vpaddq %ymm2, %ymm3, %ymm3");
}
} while ((ip += 2) < ipend);
FLETCHER_4_AVX2_SAVE_CTX(ctx);
asm volatile("vzeroupper");
kfpu_end();
}
static boolean_t fletcher_4_avx2_valid(void)

26
module/zcommon/zfs_fletcher_sse.c
View file

@ -53,6 +53,7 @@ ZFS_NO_SANITIZE_UNDEFINED
static void
fletcher_4_sse2_init(fletcher_4_ctx_t *ctx)
{
kfpu_begin();
memset(ctx->sse, 0, 4 * sizeof (zfs_fletcher_sse_t));
}
@ -80,6 +81,7 @@ fletcher_4_sse2_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp)
8 * ctx->sse[2].v[1] + ctx->sse[1].v[1];
ZIO_SET_CHECKSUM(zcp, A, B, C, D);
kfpu_end();
}
#define FLETCHER_4_SSE_RESTORE_CTX(ctx) \
@ -104,13 +106,11 @@ fletcher_4_sse2_native(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
const uint64_t *ip = buf;
const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_SSE_RESTORE_CTX(ctx);
asm volatile("pxor %xmm4, %xmm4");
for (; ip < ipend; ip += 2) {
do {
asm volatile("movdqu %0, %%xmm5" :: "m"(*ip));
asm volatile("movdqa %xmm5, %xmm6");
asm volatile("punpckldq %xmm4, %xmm5");
@ -123,11 +123,9 @@ fletcher_4_sse2_native(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
asm volatile("paddq %xmm0, %xmm1");
asm volatile("paddq %xmm1, %xmm2");
asm volatile("paddq %xmm2, %xmm3");
}
} while ((ip += 2) < ipend);
FLETCHER_4_SSE_SAVE_CTX(ctx);
kfpu_end();
}
static void
@ -136,11 +134,9 @@ fletcher_4_sse2_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
const uint32_t *ip = buf;
const uint32_t *ipend = (uint32_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_SSE_RESTORE_CTX(ctx);
for (; ip < ipend; ip += 2) {
do {
uint32_t scratch1 = BSWAP_32(ip[0]);
uint32_t scratch2 = BSWAP_32(ip[1]);
asm volatile("movd %0, %%xmm5" :: "r"(scratch1));
@ -150,11 +146,9 @@ fletcher_4_sse2_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
asm volatile("paddq %xmm0, %xmm1");
asm volatile("paddq %xmm1, %xmm2");
asm volatile("paddq %xmm2, %xmm3");
}
} while ((ip += 2) < ipend);
FLETCHER_4_SSE_SAVE_CTX(ctx);
kfpu_end();
}
static boolean_t fletcher_4_sse2_valid(void)
@ -186,14 +180,12 @@ fletcher_4_ssse3_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
const uint64_t *ip = buf;
const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_SSE_RESTORE_CTX(ctx);
asm volatile("movdqu %0, %%xmm7"::"m" (mask));
asm volatile("pxor %xmm4, %xmm4");
for (; ip < ipend; ip += 2) {
do {
asm volatile("movdqu %0, %%xmm5"::"m" (*ip));
asm volatile("pshufb %xmm7, %xmm5");
asm volatile("movdqa %xmm5, %xmm6");
@ -207,11 +199,9 @@ fletcher_4_ssse3_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
asm volatile("paddq %xmm0, %xmm1");
asm volatile("paddq %xmm1, %xmm2");
asm volatile("paddq %xmm2, %xmm3");
}
} while ((ip += 2) < ipend);
FLETCHER_4_SSE_SAVE_CTX(ctx);
kfpu_end();
}
static boolean_t fletcher_4_ssse3_valid(void)

8
module/zcommon/zfs_fletcher_superscalar.c
View file

@ -89,7 +89,7 @@ fletcher_4_superscalar_native(fletcher_4_ctx_t *ctx,
c2 = ctx->superscalar[2].v[1];
d2 = ctx->superscalar[3].v[1];
for (; ip < ipend; ip += 2) {
do {
a += ip[0];
a2 += ip[1];
b += a;
@ -98,7 +98,7 @@ fletcher_4_superscalar_native(fletcher_4_ctx_t *ctx,
c2 += b2;
d += c;
d2 += c2;
}
} while ((ip += 2) < ipend);
ctx->superscalar[0].v[0] = a;
ctx->superscalar[1].v[0] = b;
@ -129,7 +129,7 @@ fletcher_4_superscalar_byteswap(fletcher_4_ctx_t *ctx,
c2 = ctx->superscalar[2].v[1];
d2 = ctx->superscalar[3].v[1];
for (; ip < ipend; ip += 2) {
do {
a += BSWAP_32(ip[0]);
a2 += BSWAP_32(ip[1]);
b += a;
@ -138,7 +138,7 @@ fletcher_4_superscalar_byteswap(fletcher_4_ctx_t *ctx,
c2 += b2;
d += c;
d2 += c2;
}
} while ((ip += 2) < ipend);
ctx->superscalar[0].v[0] = a;
ctx->superscalar[1].v[0] = b;

8
module/zcommon/zfs_fletcher_superscalar4.c
View file

@ -113,7 +113,7 @@ fletcher_4_superscalar4_native(fletcher_4_ctx_t *ctx,
c4 = ctx->superscalar[2].v[3];
d4 = ctx->superscalar[3].v[3];
for (; ip < ipend; ip += 4) {
do {
a += ip[0];
a2 += ip[1];
a3 += ip[2];
@ -130,7 +130,7 @@ fletcher_4_superscalar4_native(fletcher_4_ctx_t *ctx,
d2 += c2;
d3 += c3;
d4 += c4;
}
} while ((ip += 4) < ipend);
ctx->superscalar[0].v[0] = a;
ctx->superscalar[1].v[0] = b;
@ -179,7 +179,7 @@ fletcher_4_superscalar4_byteswap(fletcher_4_ctx_t *ctx,
c4 = ctx->superscalar[2].v[3];
d4 = ctx->superscalar[3].v[3];
for (; ip < ipend; ip += 4) {
do {
a += BSWAP_32(ip[0]);
a2 += BSWAP_32(ip[1]);
a3 += BSWAP_32(ip[2]);
@ -196,7 +196,7 @@ fletcher_4_superscalar4_byteswap(fletcher_4_ctx_t *ctx,
d2 += c2;
d3 += c3;
d4 += c4;
}
} while ((ip += 4) < ipend);
ctx->superscalar[0].v[0] = a;
ctx->superscalar[1].v[0] = b;