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

SCVTF (vector, fixed-point, 8H from 8H)

Test 1: uops

Code:

  scvtf v0.8h, v0.8h, #3
  movi v0.16b, 1
  movi v1.16b, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 0.000

Load/store unit issues: 0.000

SIMD/FP unit issues: 1.000

retire uop (01)cycle (02)031e3f4e51schedule uop (52)schedule simd uop (54)dispatch simd uop (57)ldst uops in schedulers (5b)696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map simd uop (7e)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst simd alu (9a)l1d tlb miss (a1)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)f5f6f7f8fd
100430372306125472510001000100039816030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303723010325472510001000100039816030183037303724143289510001000100030373037111001100000373116112629100030383038303830383038
100430372206125472510001000100039816030183037303724143289510001000100030373037111001100020073116112629100030383038303830383038
100430372206125472510001000100039816030183037303724143289510001000100030373037111001100001073116112629100030383038303830383038
1004303723010325472510001000100039816030183037303724143289510001000100030373037111001100000373116112629100030383038303830383038
10043037231261254725100010001000398160301830373037241432895100010001000303730371110011000015173116112629100030383038303830383038
100430372396125472510001000100039816030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
1004303722010325472510001000100039816030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
100430372306125472510001000100039816030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038
100430372306125472510001000100039816030183037303724143289510001000100030373037111001100000073116112629100030383038303830383038

Test 2: Latency 1->2

Code:

  scvtf v0.8h, v0.8h, #3
  movi v0.16b, 1
  movi v1.16b, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 3.0037

retire uop (01)cycle (02)03181e1f3f4e51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)ld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acc2cfd5map dispatch bubble (d6)d8ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1020430037224000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000076000710116011296330100001003003830038300383003830038
102043003722400061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003008030037111020110099100100100001000000000710116011296330100001003003830038300383003830038
1020430037224000612954725101001001000010010000500427716003001830037300372826432874510100200100002001000030037300371110201100991001001000010000000150710116011296330100001003003830038300383003830038
102043003723300061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000000710116011296330100001003003830038300383003830038
102043003722500061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000000710116001296330100001003003830038300383003830038
102043003722400061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000000710116011296330100001003003830038300383003830038
102043003722500061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000000710116011296330100001003003830038300383003830038
102043003722500061295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000000000710116011296330100001003003830038300383003830038
102043003722500082295472510100100100001001000050042771600300183003730037282643287451010020010000200100003003730037111020110099100100100001000001002710116011296330100001003003830038300383003830038
1020430037225200144295382510100100100001001000050042771600300543003730037282643287451010020010000200100003003730037111020110099100100100001000000000710141011296330100001003008530038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire uop (01)cycle (02)03mmu table walk instruction (07)mmu table walk data (08)l2 tlb miss instruction (0a)l2 tlb miss data (0b)18191e1f3a3f4e51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)l1d tlb miss (a1)ld unit uop (a6)l1d cache writeback (a8)a9acc2cfd1d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1002430037225000000000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000000064004163329629010000103003830038300383003830038
100243003722500000000061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000228064003163329629010000103003830038300383003830038
1002430037225000000000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000000064003163329629010000103003830038300383003830038
1002430085225000000390061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000222064003163329629010000103003830038300383003830038
1002430037225000000000747295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000246064003163329629010000103003830038300383003830038
1002430037225000000000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000000064003163329629010000103003830038300383003830038
1002430037225000000000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000000064003163329629010000103003830038300383003830038
1002430037225000000000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000000064003163329629010000103003830038300383003830038
1002430037225000000000612954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000000064003163329629010000103003830038300383003830038
100243003722500000012001032954725100101010000101000050427716013001830037300372828632876710010201000020100003003730037111002110910101000010000100064003163329629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  scvtf v0.8h, v8.8h, #3
  scvtf v1.8h, v8.8h, #3
  scvtf v2.8h, v8.8h, #3
  scvtf v3.8h, v8.8h, #3
  scvtf v4.8h, v8.8h, #3
  scvtf v5.8h, v8.8h, #3
  scvtf v6.8h, v8.8h, #3
  scvtf v7.8h, v8.8h, #3
  movi v8.16b, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.2505

retire uop (01)cycle (02)031e3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
8020420059150030258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000030611151180160020036800001002004020040200402004020040
8020420039150030258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000000311151180160020036800001002004020040200402004020040
8020420039150030258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000000311151180160020036800001002004020040200402004020040
8020420039150030258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000000311151180160020036800001002004020040200402004020040
8020420039150051258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000000311151180160020036800001002004020040200402004020040
8020420039150030258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000010011151180160020036800001002004020040200402004020040
8020420039150030258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160020036800001002004020040200402004020040
8020420039150030258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160020036800001002004020040200402004020040
8020420039150030258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160020036800001002004020040200402004020040
8020420039150030258010810080008100800205006401322002020039200399977699908012020080032200800322003920039118020110099100100800001000000311151180160020036800001002004020040200402004020040

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.2505

retire uop (01)cycle (02)03l2 tlb miss instruction (0a)l2 tlb miss data (0b)18191e1f3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)l1d tlb miss (a1)l1d cache writeback (a8)a9acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
80024200511500000120822580010108000010800005064000012002020039200399996310019800102080000208000020039200391180021109101080000100000905038626442007580000102009220093200912009120093
80024201511501111144104446258001010800001080000506400001200612014020149100031310074802132080107208020320141201493180021109101080000102212112025020416522008680000102009920092200402009220040
800242003915000001501032580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100010305020416422003680000102004020040200402004020040
800242003915000001208225800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000105705020516242003680000102004020040200402004020040
80024200391500000120822580010108000010800005064000012002020039200399996310019800102080000208000020039200391180021109101080000100000905020516422003680000102004020040200402004020040
80024200391510000008225800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000109005020216422003680000102004020040200402004020040
8002420039150000000822580010108000010800005064000012002020039200399996310019800102080000208000020039200391180021109101080000100010005020416442003680000102004020040200402004020040
800242003915000001208225800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000106305020416422003680000102004020040200402004020040
80024200391500000120402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100010305020416422003680000102004020040200402004020040
800242003915000001204025800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000101205020416442003680000102004020040200402004020040