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 (uxth, 64-bit)

Test 1: uops

Code:

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

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 2.000

Integer unit issues: 2.001

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)
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000
100420302001200110005226510001000200020011000

Test 2: Latency 1->2

Code:

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

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 2.0030

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)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)
102042003020101201010101045290011010410206202122000110100
102042003020101201010101045290871010410208202162000110100
102042003020101201010101045290871010410208202162000110100
102042003020101201010101045290871010410208202162000110100
102042003020101201010101045290871010410208202162000110100
102042003020101201010101045290871010410208202162000110100
102042003020101201010101045290871010410208202162000110100
102042003020101201010101045290871010410208202162000110100
102042003020101201010101045290871010410208202162000110100
102042003020101201010101045290871010410208202162000110100

1000 unrolls and 10 iterations

Result (median cycles for code): 2.0030

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)
10024200302002120021100255291921002010020201242002510010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010

Test 3: Latency 1->3

Code:

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

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 2.0030

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)
10204200302010120101101045290441010410206202122000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100
10204200302010120101101045290871010410208202162000110100

1000 unrolls and 10 iterations

Result (median cycles for code): 2.0030

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)
10024200302002120021100255292151002510030200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010
10024200302002120021100205292491002010020200202001110010

Test 4: Latency 4->2

Chain cycles: 1

Code:

  subs x0, x1, w2, uxth
  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): 2.0030

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)
20204300303010130101201067892892010620212302183000120100
20204300303010130101201057892712010720214302183000120100
20204300303010130101201057897032014220258302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

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)
20024300303001130011200157894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20025300603002530025200467894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010

Test 5: Latency 4->3

Chain cycles: 1

Code:

  subs x0, x1, w2, uxth
  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): 2.0030

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)
20204300303010130101201057891292010620212302843001520100
20204300303010130101201077893692010520212302183000120100
20204300303010130101201057893692010520212302843001520100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057897142014120256302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100
20204300303010130101201057893692010520212302183000120100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 1 chain cycle): 2.0030

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)
20024300303001130011200157893572001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107897902005120072300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010
20024300303001130011200107894382001020020300203000120010

Test 6: throughput

Count: 8

Code:

  subs x0, x8, w9, uxth
  subs x1, x8, w9, uxth
  subs x2, x8, w9, uxth
  subs x3, x8, w9, uxth
  subs x4, x8, w9, uxth
  subs x5, x8, w9, uxth
  subs x6, x8, w9, uxth
  subs x7, x8, w9, uxth
  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): 0.6675

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)dispatch uop (78)map int uop (7c)map int uop inputs (7f)? int output thing (e9)? int retires (ef)
8020453416160116160116008012201099575801238022416024816001480100
8020453404160114160114008012301100076801238022416032016005980100
8020453404160114160114008012301100076801238022416024816001480100
8020453404160114160114008012301100076801238022416024816001480100
8020453404160114160114008012301100076801238022416024816001480100
8020453404160114160114008012301100076801238022416024816001480100
8020453404160114160114008012301100076801238022416024816001480100
8020453404160114160114008012301100076801238022416024816001480100
8020453404160114160114008012301100076801238022416024816001480100
8020453404160114160114008012301100076801238022416024816001480100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.6671

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)
8002453388160037160037800441107564800208002016002016001180010
8002453371160021160021800201107732800208002016002016001180010
8002453371160021160021800201107732800208002016002016001180010
8002453371160021160021800201107732800208002016002016001180010
8002553412160090160090800871107558800208002016002016001180010
8002453371160021160021800201107732800208002016002016001180010
8002453371160021160021800201107732800208002016002016001180010
8002453371160021160021800201107732800208002016002016001180010
8002553408160081160081800801107732800208002016002016001180010
8002453371160021160021800201107732800208002016002016001180010