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 (scalar, integer, S from X)

Test 1: uops

Code:

  scvtf s0, x0
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 2.000

Issues: 2.000

Integer unit issues: 0.000

Load/store unit issues: 1.000

SIMD/FP unit issues: 1.000

retire uop (01)cycle (02)03mmu table walk instruction (07)1e1f3f4f51schedule uop (52)schedule simd uop (54)schedule ldst uop (55)dispatch simd uop (57)dispatch ldst uop (58)simd uops in schedulers (5a)ldst uops in schedulers (5b)696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map ldst uop (7d)map simd uop (7e)map ldst uop inputs (80)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst simd alu (9a)ld unit uop (a6)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)f5f6f7f8fd
20043762000361225200010001000100010001407522820357376376723109200010001000100010003763761110011000100000732163337310001000377377377381377
20043763000361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000733163337310001000377377377377377
20043763000361025200010001000100010001407522820357376376723112200010001000100010003763761110011000100000733163337310001000377377377377377
20043762000361025200010001000100010001420722820357376376723109200010001000100010003763761110011000100000733163337310001000377377377377377
200437630003612125200010001000100010001407522820358376376723109200010001000100010003763761110011000100000733163337310001000377377380377377
20043763000361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000733163337310001000377377377377377
20043763000361025200010001000100010001407522820357379376723109200010001000100010003923761110011000100000733163337310001000377377377377377
20043763000361025200010001000100010001407522820357376376753109200010001000100010003763761110011000100000733163337310001000377377377377377
20043763000363025200010001000100010001407522820357376376723111200010001000100010003763761110011000100000733163337310001000379377377377377
20043763000361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000733163337310001000377377377377377

Test 2: Latency 1->2 roundtrip

Code:

  scvtf s0, x0
  fmov x0, d0
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 13.0032

retire uop (01)cycle (02)03mmu table walk data (08)18191e1f3f4f51schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)ldst uops in schedulers (5b)60696b6d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map ldst uop (7d)map simd uop (7e)map int uop inputs (7f)map ldst uop inputs (80)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)a9acbranch cond mispred nonspec (c5)cdcfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30204130032974004001300171194082540100101002000010000100200001000050062144971480270901300130130037130032125466312624030100202100002000020010000200001300321300321120201100991001010010000100010000000000131012162212951910000100001000010100130033130033130033130033130033
30204130034974000001300171194082540100101002000010000100200001000050062144971480270901300130130039130034125466312624230100200100002000020010000200001300321300321120201100991001010010000100210000000300131012162212951910000100001000010100130033130033130033130037130033
30204130033974000001300171194082540100101002000010000100200001000050062144971480270901300130130034130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000000131012162212951910000100001000010100130033130033130033130033130033
30204130032974000601300171194082540100101002000010000100200001000050062144971480270901300130130053130037125466312624030458200100602000020010000200001300321300321120201100991001010010000100010000000000131012162212951910000100001000010100130033130033130033130033130033
30204130032974000001300171194082540100101002000010000100200001000050062144971480270901300130130066130034125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000000131012162212951910000100001000010100130033130033130033130033130033
302041300329740004801300171194082540100101002000010000100200001000050062144971480270911300130130033130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000020300131012162212951910000100001000010100130033130033130033130064130035
30204130032974000001300171194082540100101002000010000100200001000050062144971480294111300130130050130033125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000000131012162212952110000100001000010100130033130033130033130033130033
30204130032974000001300171194082540100101002000010000100200001000050062144971480270901300130130047130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000002131012162212951910000100001000010100130033130038130033130033130033
30204130032974000001300171194082540100101002000010000100200001000050062144971480282301300130130060130033125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000010000131012162212951910000100001000010100130033130033130033130033130033
30204130032974000001300171194082540100101002000010000100200001000050062144971480270911300130130067130034125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000000131012162212951910000100001000010100130033130033130033130033130033

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0032

retire uop (01)cycle (02)03mmu table walk data (08)l2 tlb miss data (0b)18191e1f3f4f51schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map ldst uop (7d)map simd uop (7e)map int uop inputs (7f)map ldst uop inputs (80)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)l1d cache writeback (a8)acc2branch mispred nonspec (cb)cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
3002413003497400001200130017119408254001010010200001000010200001000050621449714801504113001313003213003212548931262683001020100002000020100002000013003213003211200211091010010100001010000000013061161312951910000100001000010010130033130033130033130033130036
3002413003297400019090130019119408254001610010200001000011200001000050623386814807028013001313003313003212548931262643001020101242000020100002000013045813003411200211091010010100001010000000012701161112952110000100001000010010130033130033130033130033130033
30024130032974000010800130018119408254001010010200001000010200001000050621449714800528113001313003213003212548931262623001020100002000020100002000013003213003211200211091010010100001010000102012701751112951910003100001000010010130033130131130034130033130033
30024130032116800002280130017119408254001010010200001000010200001000050621449714800528013001313003213003212548931262633001020100002000020100002000013003213003221200211091010010100001010000000012701162112951910000100001000010010130033130033130068130033130033
3002413003210081100276352130017119408254001010010200001000010200001000050621449714800528113001313003213003212548931262633001020100002000020100002000013003213003211200211091010010100001010000000012701161112951910000100001000010010130033130065130033130033130033
3002413003297400001200130017119408254001010010200001000010200001000050621449714800528113001313003213003212548931262623001020100002000020100002000013003213003211200211091010010100001010000000012701161112951910000100001000010010130033130033130033130033130033
3002413003297400008400130017119408254001010010200001000010200001000050621449714800528113001313003213003212548931262623001020100002000020100002000013003213003211200211091010010100001010000000012701161112951910000100001000010010130033130033130033130033130044
3002413003298600001860130017119408254001010010200001000010200001000050621449714800528013001313003213003212548931262623001020100002000020100002000013003213003211200211091010010100001010000000012701161112951910000100001000010010130033130033130033130033130033
3002413003297400001590130017119408254001010010200001000010200001000050621449714800528013001313003213003212548931262623001020100002000020100002000013003213003211200211091010010100001010000000012701161112951910000100001000010010130033130033130033130033130033
30024130032974000063352130019119408254001010010200001000010200001000050621449714800873113001313003213003212548931262623001020100002000020100002000013003213003211200211091010010100001010000000012701161212951910000100001000010010130033130033130033130033130033

Test 3: throughput

Count: 8

Code:

  scvtf s0, x8
  scvtf s1, x8
  scvtf s2, x8
  scvtf s3, x8
  scvtf s4, x8
  scvtf s5, x8
  scvtf s6, x8
  scvtf s7, x8
  mov x8, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.3340

retire uop (01)cycle (02)03mmu table walk data (08)l2 tlb miss data (0b)18191e1f3a3f4f51schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map ldst uop (7d)map simd uop (7e)map int uop inputs (7f)map ldst uop inputs (80)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)a5ld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)ea? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1602042671520000001200266982251601001008000080000100800208001550011653041884291126694267132671066366666216013520080020800242008002080020267132671311802011009910010080000100000800000110120111511701600267100080000800001002671026710267102671026719
1602042672020700000002669802516010010080000800001008002080016500116895118828820266902671326718663666661160136200800208002420080020800202671326709118020110099100100800001000008000001030111511701600267100080000800001002671426714267142671426727
16020426711200000000026699125160100100800008000010080027800205001168352188463812669526714269136625106650160142200800238002320080023800232671026714118020110099100100800001000008000002060222512712411267110080000800001002671126715267152671526811
160204267232000000120026695425160100100800008000010080023800185001170734188360702669626710267106625106649160141200800238002720080023800232671026714118020110099100100800001000008000005030222512812411267120080000800001002671126715267152671426715
160204267512000000120026699225160100100800008000010080023800185001166375188439112669526710267106625966501601402008002380027200800238002326714267131180201100991001008000010000080000010240222512712411267110080000800001002671526715267112671226715
160204267372000000000266952251601001008000080000100800238001850011574901883414126694267152671466251066501601412008002380027200800238002326710267141180201100991001008000010000080000000150222512712411267110080000800001002671426714267152671526715
160204267432000000120026700125160100100800008000010080023800185001188204188372912669526714267136625966491601412008002380023200800238002326713267141180201100991001008000010000080000020060222512812411267110080000800001002671126711267152671626719
160204272212000000120026700225160100100800008000010080023800185001167786188816312669526714267136625966501601412008002380023200800238002326714267141180201100991001008000010000080000030060222512712411267110080000800001002671626730267192673226726
1602042671720000001200266950251601001008000080000100800238001850011875491884038126695267152671466211066501601432008002380027200800238002326713267131180201100991001008000010000080000059090222512712411267110080000800001002671526716267142671526715
160204267402000000120026695225160100100800008000010080023800185001175098188454602669426715267146621106650160140200800238002320080023800232671426714118020110099100100800001000008000003030222512712411267110080000800001002671126713267142671126716

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.3339

retire uop (01)cycle (02)03mmu table walk data (08)l2 tlb miss data (0b)0f1e3f4f51schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)simd prf full (72)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map ldst uop (7d)map simd uop (7e)map int uop inputs (7f)map ldst uop inputs (80)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)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1600242671120000202669402516001010800008000010800008000050116888018838690266902670926709665303668916001020800008000020800008000026709267091180021109101080000108000000502017161717267068000080000102671026710267102671026710
1600242670920000002669402516001010800008000010800008000050116888018904630266902670926709665348366891600102080000800002080189800002707026709118002110910108000010800000050207171616267068000080000102671026710267102671026710
16002426709199000026694025160010108000080000108000080000501168880188558802669026709267096653036689160010208000080000208000080000267092670911800211091010800001080000005020716167267068000080000102671026710267102671026710
160024267092000000266940251600101080000800001080000800005011687871891037026690267092670966530366891600102080000800002080000800002670926709118002110910108000010800000650201616716267068000080000102671026713267102671026710
160024267092000000266940251600101080000800001080000800005011688801887134026690267092670966530366891600102080000800002080000800002670926709118002110910108000010800000050201716136267068000080000102671026710267102671026713
160024267092000000266940251600101080000800001080000800005011688801892336026690267092670966530366891600102080000800002080000800002670926709118002110910108000010800000050201716146267068000080000102671026710267102671026710
160024267092000100266940251600101080000800001080000800005011688801892337026690267092670966530366891600102080000800002080000800002671126709118002110910108000010800000050201616176267068000080000102671026713267102671026710
1600242670920000002669402516001010800008000010800008000050116888018917780266902670926709665303668916001020800008000020800008000026709267091180021109101080000108000000502016161616267068000080000102671026710267102671026710
1600242670920000002669402516001010800008000010800008000050116888018990630266902670926709665303668916001020800008000020800008000026709267091180021109101080000108000000502016161616267068000080000102671026710267102671026710
1600242670920000002669402516001010800008000010800008000050116888018876150266902670926709665303668916001020800008000020800008000026709267091180021109101080000108000006502016161616267068000080000102671026710267102671026710