Apple Microarchitecture Research by Dougall Johnson

M1/A14 P-core (Firestorm): Overview | Base Instructions | SIMD and FP Instructions
M1/A14 E-core (Icestorm):  Overview | Base Instructions | SIMD and FP Instructions

SUBS (register, 32-bit)

Test 1: uops

Code:

  subs w0, w0, w1
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 1.001

Load/store unit issues: 0.000

SIMD/FP unit issues: 0.000

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
100410301001100110002504310001000200010011000
100410301001100110002504310001000200010011000
100410301001100110002504310001000200010011000
100410301001100110002504310001000200010011000
100410301001100110002504310001000200010011000
100410301001100110002504310001000200010011000
100410301001100110002504310001000200010011000
100410301001100110002504310001000200010011000
100410301001100110002504310001000200010011000
100410301001100110002504310001000200010011000

Test 2: Latency 1->2

Code:

  subs w0, w0, w1
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10204100301010110101101092515201010610206202201000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100

1000 unrolls and 10 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10024100301002110021100292531291003010030200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010

Test 3: Latency 1->3

Code:

  subs w0, w1, w0
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10204100301010110101101092515981010810210202121000110100
10204100301010110101101082517741010810208202201000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100
10204100301010110101101082517741010810208202161000110100

1000 unrolls and 10 iterations

Result (median cycles for code): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
10024100301002110021100302532921002810030200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202531611002010020200201001110010
10024100301002110021100202530491002810031200401001110010

Test 4: Latency 4->2

Chain cycles: 1

Code:

  subs w0, w1, w2
  cset x1, cc
  mov x0, 1
  mov x1, 2
  mov x2, 3
  mov x3, 4
  mov x4, 5

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code, minus 1 chain cycle): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
20204200302010120101201075191972010820214302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 1 chain cycle): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
20024200302001120011200185196382001820036300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105196382001820034300442000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010

Test 5: Latency 4->3

Chain cycles: 1

Code:

  subs w0, w1, w2
  cset x2, cc
  mov x0, 1
  mov x1, 2
  mov x2, 3
  mov x3, 4
  mov x4, 5

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code, minus 1 chain cycle): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
20204200302010120101201075193202010820214302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100
20204200302010120101201085195482010820216302242000120100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 1 chain cycle): 1.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
20024200302001120011200185195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200802003220032200545195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010
20024200302001120011200105195982001020020300202000120010

Test 6: throughput

Count: 8

Code:

  subs w0, w8, w9
  subs w1, w8, w9
  subs w2, w8, w9
  subs w3, w8, w9
  subs w4, w8, w9
  subs w5, w8, w9
  subs w6, w8, w9
  subs w7, w8, w9
  mov x8, 9
  mov x9, 10
  mov x10, 11

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.5010

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
802044008780110801108011324034580115802161602328001280100
802044008180112801128011524034580115802161602328001280100
802044008180112801128011524034580115802161602328001280100
802044008180112801128011524034580115802161602328001280100
802044009380112801128011524034580115802161602328001280100
802044008180112801128011524034580115802161602328001280100
802044008180112801128011524034580115802161602328001280100
802044008180112801128011524034580115802161602328001280100
802044008180112801128011524034580115802161602328001280100
802044008180112801128011524034580115802161602328001280100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.5004

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)dispatch int uop (56)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
800244035380034800348003724006780020800201600208001180010
800244003080021800218002024006580020800201600208001180010
800244026280159801598015824006580020800201603048015380010
800244003080021800218002024006580020800201600208001180010
800244003080021800218002024006580020800201600208001180010
800244003080021800218002024006580020800201600208001180010
800244003080021800218002024006580020800201600208001180010
800244003080021800218002024020780068800681600208001180010
800244240380021800218002024006580020800201600888004180010
800244003080021800218002024006580020800201600208001180010