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, 4S from 4S)

Test 1: uops

Code:

  scvtf v0.4s, v0.4s, #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)03181e3f4e51schedule uop (52)schedule simd uop (54)dispatch simd uop (57)ldst uops in schedulers (5b)60696d6emap 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 cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)f5f6f7f8fd
10043037220029325472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303722006125472510001000100039816013018303730372414328951000100010003037303711100110000073116122629100030383038303830383038
1004303723006125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303722008225472510001000100039816013018303730372414328951000100010003037303711100110000073116212629100030383038303830383038
1004303722006125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303722008225472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723006125382510001000100039816013018303730372414328951000100011613037303711100110000073116112629100030383038303830383038
1004303723006125472510001000100039816013018307330372414328951000100010003037303711100110000073116112629100030383038303830383038
1004303723006125472510001000100039816013018303730372414328951000100010003037303711100110000073116112629100030383038303830383038
1004308523006125472510001000100039816013018303730372414328951000100010003037303711100110000073216112629100030383038303830383038

Test 2: Latency 1->2

Code:

  scvtf v0.4s, v0.4s, #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)031e3f4e51schedule 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 cache writeback (a8)acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
10204300372254261295472510100100100001001000050042771601300183003730037282716287411010020010008200100083003730037111020110099100100100001000001117180160029645100001003003830038300383003830038
1020430037225061295472510100100100001001000050042771601300183003730037282717287401010020010008200100083003730037111020110099100100100001000001117170160029645100001003003830038300383003830038
1020430037224061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000007101161129633100001003003830038300383003830038
102043003722515631295472510100100100001001000050042771601300183003730037282643287451041020010000200100003003730037111020110099100100100001000040007101161129633100001003003830038300383003830038
10204300372252461295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000007101161129633100001003003830038300383003830038
1020430037225061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000007101161129633100001003003830038300383003830038
1020430037225061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000007101161129633100001003003830038300383003830038
1020430037225061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000007101161129633100001003003830038300383003830038
10204300372251861295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000007101162129633100001003003830038300383003830038
1020430037224061295472510100100100001001000050042771601300183003730037282643287451010020010000200100003003730037111020110099100100100001000000007101161129633100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire uop (01)cycle (02)03mmu table walk data (08)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)a9acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
10024300372250000000103295472510010101000010100005042771601300183003730037282863287671001020100002010000300373003711100211091010100001000000306402162229629010000103003830038300383003830085
100243003722500001200103295472510012121000010100005042771601300183003730037282863287671001220100002010000300373003711100211091010100001000010006402162229629010000103003830038300383003830038
100243003722400001200103295472510010101000010100005042771601300183003730037282863287671001220100002010000300373003711100211091010100001000010006402162229631010000103003830038300383003830038
100243003722500001200869295472510012101000010100006042771601300183003730037282863287671001020100002010000300373003711100211091010100001000010306402162229629010000103003830038300383003830038
100243003722501001200103295472510010101000010100005042771601300183003730037282863287671001220100002010000300373003711100211091010100001000010006402165329631010000103003830038300383003830038
100243003722400001200103295472510010101000010100005042771601300183003730037282863287851001020100002010000300373003711100211091010100001000010306402162229629010000103003830038300383003830038
100243003722500001200103295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000006402162229629010000103003830038300383003830038
100243003722500001200441295472510010101000010100006042771601300183003730037282863287671001020100002010000300373003711100211091010100001000010026402162229629010000103003830038300383003830038
10024300372250000000103295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000010306408162229629210000103003830038300383003830038
100243003722500001200103295472510012101000012100006042771600300183003730037282863287671001020100002010000300373003721100211091010100001000010306422162229629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  scvtf v0.4s, v8.4s, #3
  scvtf v1.4s, v8.4s, #3
  scvtf v2.4s, v8.4s, #3
  scvtf v3.4s, v8.4s, #3
  scvtf v4.4s, v8.4s, #3
  scvtf v5.4s, v8.4s, #3
  scvtf v6.4s, v8.4s, #3
  scvtf v7.4s, v8.4s, #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)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 cache writeback (a8)acbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)dde0? simd retires (ee)? int retires (ef)f5f6f7f8fd
80204200601501272258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100031115135116020036800001002004020040200402004020040
80204200391501230258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100031115118016020036800001002004020040200402004020040
80204200391501272258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100031115118016020036800001002004020040200402004020040
80204200391501272258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100131115118016020036800001002004020040200402004020040
80204200391503972258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100031115118016020036800001002004020040200402004020040
80204200391506330258010810080008100800205006401321200202003920039997769990801202008003220080141200392003911802011009910010080000100001115118016020036800001002004020040200402004020040
80204200391501272258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100001115118016020036800001002004020040200402004020040
80204200391502772258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100131115118016020036800001002004020040200402004020040
80204200391501272258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100131115118016020036800001002004020040200402004020040
80204200391506072258010810080008100800205006401321200202003920039997769990801202008003220080032200392003911802011009910010080000100101115118016020036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)03l1i tlb fill (04)1e3f51schedule 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 cache writeback (a8)acbranch cond mispred nonspec (c5)cfl1i tlb miss demand (d4)d5map dispatch bubble (d6)ddfetch restart (de)e0? simd retires (ee)? int retires (ef)f5f6f7f8fd
80024200401500128225800101080000108000050640000120020200392003999943100198001020800002080000200392003911800211091010800001000050211141614162003680000102004020040200402004020040
8002420039150198225800101080000108000050640000120020200392003999943100198001020800002080000200392003911800211091010800001003050211171618162003680000102004020040200402004020040
800242003915012288225800101080000108000050640000120020200392003999943100198001020800002080000200392003911800211091010800001013050211161616172003680000102004020040200402004020040
80024200391501368225800101080000108000050640000020020200392003999923100198001020800002080000200392003911800211091010800001000050211161617162003680000102004020040200402004020040
800242003915010402580010108000010800005064000002002020039200399992310019804352080000208000020039200391180021109101080000100005021116169182003680000102004020040200402004020040
8002420039150104025800101080000108000050640000020020200392003999923100198001020800002080000200392003911800211091010800001000050211171617172003680000102004020040200402004020040
8002420039150139402580010108000010800005064000002002020039200399994310019800102080000208000020039200391180021109101080000100005021117168172003680000102004020040200402004020040
80024200391501042025800101080000108000050640000020020200392003999943100198001020800002080000200392003911800211091010800001000150211161616162003680000102004020040200402004020040
8002420039150104025800101080000108000050640000120020200392003999943100198001020800002080000200392003911800211091010800001000050211171610172003680000102004020040200402004020040
800242003915010402580010108000010800005064000012002020039200399994310019800102080000208000020039200391180021109101080000100005021181618132003680000102004020040200402004020040