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

LD1 (multiple, post-index, 4 regs, 16B)

Test 1: uops

Code:

  ld1 { v0.16b, v1.16b, v2.16b, v3.16b }, [x6], x8
  nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop ; nop
  mov x0, 1
  mov x1, 2
  mov x8, 0

(no loop instructions)

1000 unrolls and 1 iteration

Retires (minus 60 nops): 4.000

Issues: 5.000

Integer unit issues: 1.001

Load/store unit issues: 4.000

SIMD/FP unit issues: 0.000

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)dispatch int uop (56)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)dispatch uop (78)map ldst uop (7d)map ldst uop inputs (80)? int output thing (e9)? ldst retires (ed)
64005300535011100340081002400030001200050004000500010014000
64004295355001100140001000400030001200050004000500010014000
64004294665001100140001000400030001200050004000500010014000
64004294855001100140001000400030001200050004000500010014000
64004294655001100140001000400030001200050004000500010014000
64004294655001100140001000400030001200050004000500010014000
64004294645001100140001000400030001200050004000500010014000
64004294635001100140001000400030001200050004000500010014000
64005294815006100240041001400030001200050004000500010014000
64004294655001100140001000400030001200050004000500010014000

Test 2: throughput

Count: 8

Code:

  ld1 { v0.16b, v1.16b, v2.16b, v3.16b }, [x6], x8
  ld1 { v0.16b, v1.16b, v2.16b, v3.16b }, [x6], x8
  ld1 { v0.16b, v1.16b, v2.16b, v3.16b }, [x6], x8
  ld1 { v0.16b, v1.16b, v2.16b, v3.16b }, [x6], x8
  ld1 { v0.16b, v1.16b, v2.16b, v3.16b }, [x6], x8
  ld1 { v0.16b, v1.16b, v2.16b, v3.16b }, [x6], x8
  ld1 { v0.16b, v1.16b, v2.16b, v3.16b }, [x6], x8
  ld1 { v0.16b, v1.16b, v2.16b, v3.16b }, [x6], x8
  mov x7, x6
  mov x8, x6
  mov x9, x6
  mov x10, x6
  mov x11, x6
  mov x12, x6
  mov x13, x6
  mov x8, 0

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 2.0006

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)dispatch int uop (56)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)dispatch uop (78)map int uop (7c)map ldst uop (7d)map int uop inputs (7f)map ldst uop inputs (80)? int output thing (e9)? ldst retires (ed)? int retires (ef)
3202051601674001528011632003680116320010240309100819440011320032001620040002080003320000100
3202041600544001098010332000680103320010240309256002440011320032001620040002080003320000100
3202051600984001528011632003680116320010240309256002440011320032001620040002080003320000100
3202041600474001038010332000080103320010240309256002440011320032001620040002080003320000100
3202041600474001038010332000080103320010240309256002440011320032001620040002080003320000100
3202041600474001038010332000080103320010240309256002440011320032001620040009080016320000100
3202041600474001038010332000080103320010240309256882640011320032001620040002080003320000100
3202041600474001038010332000080103320010240309256002440011320032001620040002080003320000100
3202041600474001038010332000080103320010240309256002440011320032001620040002080003320000100
3202041600474001038010332000080103320010240309256002440011320032001620040002080003320000100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 2.0005

retire uop (01)cycle (02)schedule uop (52)schedule int uop (53)schedule ldst uop (55)dispatch int uop (56)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)dispatch uop (78)map int uop (7c)map ldst uop (7d)map int uop inputs (7f)map ldst uop inputs (80)? int output thing (e9)? ldst retires (ed)? int retires (ef)
3200251601834000628002632003680026320010240039256002440002320320016204000208000332000010
3200241600434000118001132000080010320058240078125228640008420320072204000008000132000010
3200241600514000118001132000080010320000240030255998240001020320000204000008000132000010
3200241600434000118001132000080010320000240030255998240001020320000204000908001632000010
3200241600554000118001132000080010320000240030255998240001020320000204000008000132000010
3200251601074000568002632003080026320000240030255998240001020320000204000008000132000010
3200241600434000118001132000080010320000240030255998240001020320000204000008000132000010
3200241600434000118001132000080010320000240030255998240001020320000204000008000132000010
3200241600434000118001132000080010320000240030255998240001020320000204000908001632000010
3200241600434000118001132000080010320000240030255998240001020320000204000008000132000010