libbb/sha1: x86_64 version: reorder prologue/epilogue insns

Not clear exactly why, but this increases hashing speed
on Skylake from 454 MB/s to 464 MB/s.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2022-01-04 01:45:13 +01:00
parent 1fc520ed28
commit c3cfcc9242
2 changed files with 71 additions and 64 deletions

View File

@ -6,14 +6,14 @@
.hidden sha1_process_block64
.type sha1_process_block64, @function
.balign 8 # allow decoders to fetch at least 4 first insns
.balign 8 # allow decoders to fetch at least 5 first insns
sha1_process_block64:
pushq %r15 #
pushq %r14 #
pushq %r13 #
pushq %r12 #
pushq %rbp #
pushq %rbx #
pushq %rbp # 1 byte insn
pushq %rbx # 1 byte insn
pushq %r15 # 2 byte insn
pushq %r14 # 2 byte insn
pushq %r13 # 2 byte insn
pushq %r12 # 2 byte insn
pushq %rdi # we need ctx at the end
#Register and stack use:
@ -22,24 +22,6 @@ sha1_process_block64:
# esi,edi: temps
# -32+4*n(%rsp),r8...r15: W[0..7,8..15]
# (TODO: actually W[0..7] are used a bit more often, put _them_ into r8..r15?)
movq 4*8(%rdi), %r8
bswapq %r8
movl %r8d, %r9d
shrq $32, %r8
movq 4*10(%rdi), %r10
bswapq %r10
movl %r10d, %r11d
shrq $32, %r10
movq 4*12(%rdi), %r12
bswapq %r12
movl %r12d, %r13d
shrq $32, %r12
movq 4*14(%rdi), %r14
bswapq %r14
movl %r14d, %r15d
shrq $32, %r14
movl $3, %eax
1:
movq (%rdi,%rax,8), %rsi
@ -48,12 +30,30 @@ sha1_process_block64:
movq %rsi, -32(%rsp,%rax,8)
decl %eax
jns 1b
movl 80(%rdi), %eax # a = ctx->hash[0]
movl 84(%rdi), %ebx # b = ctx->hash[1]
movl 88(%rdi), %ecx # c = ctx->hash[2]
movl 92(%rdi), %edx # d = ctx->hash[3]
movl 96(%rdi), %ebp # e = ctx->hash[4]
movq 4*8(%rdi), %r8
movq 4*10(%rdi), %r10
bswapq %r8
bswapq %r10
movq 4*12(%rdi), %r12
movq 4*14(%rdi), %r14
bswapq %r12
bswapq %r14
movl %r8d, %r9d
shrq $32, %r8
movl %r10d, %r11d
shrq $32, %r10
movl %r12d, %r13d
shrq $32, %r12
movl %r14d, %r15d
shrq $32, %r14
# 0
# W[0], already in %esi
movl %ecx, %edi # c
@ -1272,17 +1272,17 @@ sha1_process_block64:
rorl $2, %ecx # b = rotl32(b,30)
popq %rdi #
addl %eax, 80(%rdi) # ctx->hash[0] += a
addl %ebx, 84(%rdi) # ctx->hash[1] += b
addl %ecx, 88(%rdi) # ctx->hash[2] += c
addl %edx, 92(%rdi) # ctx->hash[3] += d
addl %ebp, 96(%rdi) # ctx->hash[4] += e
popq %rbx #
popq %rbp #
popq %r12 #
addl %eax, 80(%rdi) # ctx->hash[0] += a
popq %r13 #
addl %ebx, 84(%rdi) # ctx->hash[1] += b
popq %r14 #
addl %ecx, 88(%rdi) # ctx->hash[2] += c
popq %r15 #
addl %edx, 92(%rdi) # ctx->hash[3] += d
popq %rbx #
addl %ebp, 96(%rdi) # ctx->hash[4] += e
popq %rbp #
ret
.size sha1_process_block64, .-sha1_process_block64

View File

@ -15,14 +15,14 @@ echo \
.hidden sha1_process_block64
.type sha1_process_block64, @function
.balign 8 # allow decoders to fetch at least 4 first insns
.balign 8 # allow decoders to fetch at least 5 first insns
sha1_process_block64:
pushq %r15 #
pushq %r14 #
pushq %r13 #
pushq %r12 #
pushq %rbp #
pushq %rbx #
pushq %rbp # 1 byte insn
pushq %rbx # 1 byte insn
pushq %r15 # 2 byte insn
pushq %r14 # 2 byte insn
pushq %r13 # 2 byte insn
pushq %r12 # 2 byte insn
pushq %rdi # we need ctx at the end
#Register and stack use:
@ -31,24 +31,6 @@ sha1_process_block64:
# esi,edi: temps
# -32+4*n(%rsp),r8...r15: W[0..7,8..15]
# (TODO: actually W[0..7] are used a bit more often, put _them_ into r8..r15?)
movq 4*8(%rdi), %r8
bswapq %r8
movl %r8d, %r9d
shrq $32, %r8
movq 4*10(%rdi), %r10
bswapq %r10
movl %r10d, %r11d
shrq $32, %r10
movq 4*12(%rdi), %r12
bswapq %r12
movl %r12d, %r13d
shrq $32, %r12
movq 4*14(%rdi), %r14
bswapq %r14
movl %r14d, %r15d
shrq $32, %r14
movl $3, %eax
1:
movq (%rdi,%rax,8), %rsi
@ -57,11 +39,29 @@ sha1_process_block64:
movq %rsi, -32(%rsp,%rax,8)
decl %eax
jns 1b
movl 80(%rdi), %eax # a = ctx->hash[0]
movl 84(%rdi), %ebx # b = ctx->hash[1]
movl 88(%rdi), %ecx # c = ctx->hash[2]
movl 92(%rdi), %edx # d = ctx->hash[3]
movl 96(%rdi), %ebp # e = ctx->hash[4]
movq 4*8(%rdi), %r8
movq 4*10(%rdi), %r10
bswapq %r8
bswapq %r10
movq 4*12(%rdi), %r12
movq 4*14(%rdi), %r14
bswapq %r12
bswapq %r14
movl %r8d, %r9d
shrq $32, %r8
movl %r10d, %r11d
shrq $32, %r10
movl %r12d, %r13d
shrq $32, %r12
movl %r14d, %r15d
shrq $32, %r14
'
W32() {
test "$1" || exit 1
@ -71,6 +71,13 @@ test "$1" -lt 8 && echo "-32+4*$1(%rsp)"
test "$1" -ge 8 && echo "%r${1}d"
}
# It's possible to interleave insns in rounds to mostly eliminate
# dependency chains, but this likely to only help old Pentium-based
# CPUs (ones without OOO, which can only simultaneously execute a pair
# of _adjacent_ insns).
# Testing on old-ish Silvermont CPU (which has OOO window of only
# about ~8 insns) shows very small (~1%) speedup.
RD1A() {
local a=$1;local b=$2;local c=$3;local d=$4;local e=$5
local n=$(($6))
@ -257,17 +264,17 @@ RD2 ax bx cx dx bp 75; RD2 bp ax bx cx dx 76; RD2 dx bp ax bx cx 77; RD2 cx dx b
echo "
popq %rdi #
addl %eax, 80(%rdi) # ctx->hash[0] += a
addl %ebx, 84(%rdi) # ctx->hash[1] += b
addl %ecx, 88(%rdi) # ctx->hash[2] += c
addl %edx, 92(%rdi) # ctx->hash[3] += d
addl %ebp, 96(%rdi) # ctx->hash[4] += e
popq %rbx #
popq %rbp #
popq %r12 #
addl %eax, 80(%rdi) # ctx->hash[0] += a
popq %r13 #
addl %ebx, 84(%rdi) # ctx->hash[1] += b
popq %r14 #
addl %ecx, 88(%rdi) # ctx->hash[2] += c
popq %r15 #
addl %edx, 92(%rdi) # ctx->hash[3] += d
popq %rbx #
addl %ebp, 96(%rdi) # ctx->hash[4] += e
popq %rbp #
ret
.size sha1_process_block64, .-sha1_process_block64