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

SUB (sxtw, 64-bit)

Test 1: uops

Code:

  sub x0, x0, w1, sxtw
  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:

  sub x0, x0, w1, sxtw
  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)
10204200302010120101101045290661010410210202202000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100

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)
10024200302002120021100255292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205312131016010179200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020201242002510010

Test 3: Latency 1->3

Code:

  sub x0, x1, w0, sxtw
  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)
10204200302010120101101045291001010410210202202000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212203022001610100
10204200302010120101101045291861010410212202242000110100
10204200302010120101101045291861010410212202242000110100

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)
10024200302002120021100255291971002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010
10024200302002120021100205292531002010020200202001110010

Test 4: throughput

Count: 8

Code:

  sub x0, x8, w9, sxtw
  sub x1, x8, w9, sxtw
  sub x2, x8, w9, sxtw
  sub x3, x8, w9, sxtw
  sub x4, x8, w9, sxtw
  sub x5, x8, w9, sxtw
  sub x6, x8, w9, sxtw
  sub x7, x8, w9, sxtw
  mov x8, 9
  mov x9, 10

(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)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)
8020453404160117160117801301360838801308023716026816001580100
8020453415160116160116801291360838801308023616027216001780100
8020453404160117160117801301360838801308023716027216001780100
8020453404160117160117801301360838801308023616027216001780100
8020453404160117160117801301360838801308023616027216001780100
8020453404160117160117801301360838801308023616027216001780100
8020453404160117160117801301360838801308023616027216001780100
8020453404160117160117801301360838801308023616027216001780100
8020453404160117160117801301360838801308023616027216001780100
8020453404160117160117801301360838801308023616027216001780100

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)
8002453402160039160039800511360232800518005716002016001180010
8002453371160021160021800201359903800208002016002016001180010
8002453371160021160021800201359903800208002016002016001180010
8002453371160021160021800201359903800208002016002016001180010
8002453371160021160021800201359903800208002016002016001180010
8002453371160021160021800201359903800208002016002016001180010
8002453371160021160021800201359903800208002016002016001180010
8002453371160021160021800201359903800208002016002016001180010
8002453371160021160021800201359903800208002016002016001180010
8002453371160021160021800201359903800208002016019616007480010