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, H from W)

Test 1: uops

Code:

  scvtf h0, w0
  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)0318191e3f4f51schedule 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)simd prf full (72)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)a5ld unit uop (a6)l1d cache writeback (a8)acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)f5f6f7f8fd
20043763000361025200010001000100010001407522820357376376720310920001000100010001000376376111001100001000100731161137310001000377377377377377
20043762000361025200010001000100010001407522820357376376720310920001000100010001000389376111001100001000030731161137310001000377377377381377
20043762000372025200010001000100010001407522820357376376720310920001000100010001000376376111001100001000000731161137310001000377377377377377
20043762000361225200010001000100010001407522820357376376720310920001000100010001189378376111001100001000000731161137310001000377377377377380
20043762000361025200010001000100010001407522820357376376720310920001000100010001000376376111001100001000000731161137310001000377377377380377
20043763000371025200010001000100010001407522820357376376720310920001000100010001000376376111001100001000000731161137310001000377377378377377
20043763000361025200010001000100010001407522820357376376720310920001000100010001000376376111001100001000000731161137310001000377381377377377
20043763000361025200010001000100010001407522820357376376720310920001000100010001000376376111001100001000000731161137310001000377377377377377
20043763000361025200010001000100010001407522820357376376720310920001000100010001000376376111001100001000000731161137310001000377377377377377
20043763000361025200010001000100010001407522820357376376720310920001000100010001000376376111001100001000000731161137710001000377377377377377

Test 2: Latency 1->2 roundtrip

Code:

  scvtf h0, w0
  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)03l1i tlb fill (04)1e1f3f4f51schedule 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)ld unit uop (a6)l1d cache writeback (a8)a9acc2cfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30204130032974030130017119408254010010100200001000010020000100005006214545148027090130013130032130032125466312624030100202100002000020010000200001300341300321120201100991001010010000100001000041030131012162212951910027100001000010100130034130033130034130033130044
3020413003297400013001711940825401001011520000100021002000010000500621449714803669013010713003213003212546631262403010020010000200002021000020000130032130032112020110099100101001000010000100003030131012162212951910000100001000010100130033130033130033130033130034
3020413003297400013001711940825401001010020000100001002000010000500621449714802709013001613003213011912546631262403010020010061200002001000020000130119130033112020110099100101001000010000100001200131012162212951910000100001000010100133420133651133056133585134021
302041334761029700130017119408254010010100200001000010020000100005006214497148027090130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100001000049000131012162212951910000100001000010100130033130033130033130033130059
30204130032974000130017119408254010010100200001000010020000100005006214497148027090130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100001000059000131012162212951910000100001000010100130033130033130033130033130065
3020413003297409013001711940825401001010020000100001002000010000500621449714802709013001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010000100002000131012162212951910000100001000010100130033130033130033130033130062
30204130032974000130017119408254010010100200061000210020000100005006214497148027090130013130124130032125466312624130100200100002000020010000200001300321300321120201100991001010010000100001000065000131012162212951910000100001000010100130033130033130033130033130051
30204130032974000130017119408254010010100200001000010020000100005006214497148027090130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100001000055000131012162212951910000100001000010100130033130033130033130033130033
302041300329730120130017119408254010010100200001000010020000100005006214497148027090130013130032130032125466312624030100200100002000020010067200001300321300321120201100991001010010000100001000041030131012162212951910000100001000010100130033130033130033130033130084
3020413003297400013001711940825401001010020000100001002000010000500621449714802709013001313003213003212546731262403010020010000200002001000020000130032130032112020110099100101001000010000100000000131012162212951910000100001000010100130033130033130033130033130041

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0032

retire uop (01)cycle (02)03mmu table walk data (08)18191e3f4f51schedule 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)9fld unit uop (a6)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
300241300329740003013001711944168400101001620000100001020000100495062219171480052801300130130032130034125491312629530820201000020000201000020000130121130205112002110910100101000010100000312701165112952010000100001000010010130033130034130036130033130033
300241300329740001213001711941025400101001020000100001020000100005062146411480052811300130130032130032125489312631430010201000020000201000020000130032130032112002110910100101000010100043312725161112951910000100001000010010130033130033130034130033130036
300241300339990001213001711940825400101001020000100001020000100005062144971480086111300130130032130032125493312629830010201000020000201000020000130062130032112002110910100101000010100009312702161112951910000100001000010010130033130034130036130036130033
300241300339750104813001711940825400101001020000100001020000100005062144971480087011300133130032130034125489312630330010201000020000201000020000130032130033112002110910100101000010100001012701162112951910000100001000010010130033130033130033130033130033
30024130032974000013001711940825400101001020000100001020000100005062144971480064011300130130039130036125489312631130010201000020000201000020000130032130032112002110910100101000010100001012701161112951910000100001000010010130036130033130033130035130035
300241300349950001213001711941025400101001020000100001020000100005062144971480097911300130130036130032125489312631530010201000020000201000020000130032130035112002110910100101000010100001312721161212951910000100001000010010130033130033130033130033130033
30024130032974000013001711940825400101001020000100001020000100005062144971480052811300130130032130032125489312630830010201000020000201000020000130032130032112002110910100101000010100000012701161112951910000100001000010010130114130033130033130033130033
30024130032974001102913001711940825400101001020000100001020000100005062144971480052811300130130032130032125489312631330010201000020000201000020000130032130032112002110910100101000010100000012701162112951910000100001000010010130033130063130033130033130033
30024130032974000013001711940825400101001020000100001020000100005062144971480052811300130130032130032125489312630030010201000020000201000020000130032130032112002110910100101000010100000012701162112951910000100001000010010130033130033130033130033130033
30024130032974000013001711940825400101001020000100001020000100005062144971480052811300130130032130032125489312630630010201000020000201000020000130032130032112002110910100101000010100001012701161112951910000100001000010010130033130033130033130033130033

Test 3: throughput

Count: 8

Code:

  scvtf h0, w8
  scvtf h1, w8
  scvtf h2, w8
  scvtf h3, w8
  scvtf h4, w8
  scvtf h5, w8
  scvtf h6, w8
  scvtf h7, w8
  mov x8, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

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

retire uop (01)cycle (02)03181e3f4f51schedule 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 miss (a1)a5ld unit uop (a6)l1d cache writeback (a8)a9acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)fetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
160204267131990122669822516010010080000800001008002080014500117394218844241266942671426713663666662160134200800248002420080020800242670926713118020110099100100800001000080000360001115117016026706080000800001002671426714267142671426854
160204267132000122669902516010010080000800001008002080016500116816618838981266902671326713663666662160136200800208002020080020800202671326713118020110099100100800001000080000360301115117016026711080000800001002671026710269192680026723
16020426713200012266982251601001008000080000100800208001550011787871884163026694267142671366366666216013420080020800242008002080024267132671311802011009910010080000100008000040301115117016026710080000800001002671526714267102671026742
16020426753201012266982251601001008000080000100802088019950011689511888873126694267092671366366666216013420080020800202008002080020267092671411802011009910010080000100008000025093501115117016026710080000800001002671426710267102671426962
16020426713200002669412516010010080000800001008002080015500116895118862541266942671326709663666662160135200800208002020080020800202671426713118020110099100100800001000080000350001115117016026710080000800001002671426715268952674126723
16020426713200002669822516010010080000800001008002080014500116860518847751266942671326710663266662160134200800208002020080024800202671326709118020110099100100800001000080000680601115117016026706080000800001002671026714267102671526950
160204267152000122669472516010010080000800001008002080015500116895118890120266942671326709663266662160135200800208002020080020800202670926713118020110099100100800001000080000610601115117016026711080000800001002671026714267102671026919
160204267152000122669422516010010080000800001008002080016500117005918841631266942671326713663666658160135200800208002020080024800202671326713118020110099100100800001000080000420301115117016026710080000800001002671426714267142671426712
16020426712200002669422516010010080000800001008039680015500117885218851570266942671326714663266659160136200800208002020080024800202671426710118020110099100100800001000080000680901115117016026710080000800001002671426715267102671026949
16020426713200012266993251601001008000080000100800208001450011685971884201126691267092671466366666216013520080024800202008002080024267132671311802011009910010080000100008000050001115117016026710080000800001002671526710267142671026895

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)03mmu table walk data (08)1e3f4f51schedule 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)a9accfd5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
160024267102000026694125160010108000080000108000080000501168880188344302669026709267096653366891600102080000800002080000800002670926709118002110910108000010800006300502081653267068000080000102671026710267102671026929
160024267152000026694025160010108000080000108000080000501168568188403212669026709267096653366891600102080000800002080000800002670926709118002110910108000010800005906502051664267068000080000102671026710267102671026935
160024267222000026694425160790108000080000108000080000501183157188403202669026709267096653366891600102080000800002080000800002670926709118002110910108000010800006009502031635267068000080000102671026710267102671026934
160024267242000026694025160010108000080000108000080000501168880188403202669026709267096653366891600102080000800002080000800002670926709118002110910108000010800006109502061664267068000080000102671026710267102671026944
1600242672120000266949251600101080000800001080000800005011688801884032026690267092670966533668916001020800008000020800008000026709267091180021109101080000108000067015502031664267068000080000102671026710267102671026945
160024267202000026694025160010108000080000108000080000501168880188403212669026709267096655366891600102080000800002080000800002670926709118002110910108000010800006309502061653267068000080000102671026710267102671026934
160024267302000026694025160010108000080000108000080000501168880188403202669026709267096653366891600102080000800002080000800002670926709118002110910108000010800004400502031655267068000080000102671026710267102671026948
160024267202000026694025160010108000080000108000080000501176821188368102669026709267096653366891600102080000800002080000800002670926709118002110910108000010800006903502031635267068000080000102671026710267102671026961
1600242672220000266941725160010108000080000108000080000501168880188403202669026709267096653366891600102080000800002080000800002670926709118002110910108000010800006803502051655267068000080000102671026710267102671026816
160024267092000026694025160010108000080000108000080000501168880188403202669026709267096653366891600102080000800002080000800002670926709118002110910108000010800007006502051646267068000080000102671026710267102671026954