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

MRS (CNTVCT_EL0)

Test 1: uops

Code:

  mrs x0, cntvct_el0

(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)? int output thing (e9)? int retires (ef)
100412791001100110011000
100412791001100110011000
100412791001100110011000
100412791001100110011000
100412791001100110011000
100412791001100110011000
100412791001100110011000
100412791001100110011000
100412791001100110011000
100412791001100110011000

Test 2: throughput

Count: 8

Code:

  mrs x0, cntvct_el0
  mrs x1, cntvct_el0
  mrs x2, cntvct_el0
  mrs x3, cntvct_el0
  mrs x4, cntvct_el0
  mrs x5, cntvct_el0
  mrs x6, cntvct_el0
  mrs x7, cntvct_el0

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 1.2504

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)
8020410003580101801011003001002002008000180100
8020410003580101801011003001002002008000180100
8020410003580101801011003001002002008000180100
8020410003580101801011003001002002008000180100
8020510006480109801091003001002002008000180100
8020410003580101801011003001002002008000180100
8020410003580101801011003001002002008000180100
8020410003580101801011003001002002008000180100
8020410003580101801011003001002002008000180100
8020410003580101801011003001002002008001080100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 1.2504

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)map ldst uop inputs (80)map simd uop inputs (81)? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)
800241000358001180011103010202000800010080010
800241000298001180011103010202000800010080010
800251000648002080020103010202000800010080010
800241000298001180011103010202000800010080010
800241000298001180011103010202000800010080010
800241000298001180011103010202000800010080010
800241000298001180011103010202000800010080010
800241000298001180011103010202000800010080010
800251000598001980019103010202000800010080010
800241000298001180011103010202000800010080010