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, fixed-point, D from W)

Test 1: uops

Code:

  scvtf d0, w0, #3
  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)031e3f4f51schedule 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
200437630361025200010001000100010001411222820357376376723109200010001000100010003763761110011000100000733161137310001000377377377377377
200437620361025200010001000100010001407522820357376376723109200010001000100010003793761110011000100000731161137310001000377377377377377
200437630361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100003731161137310001000378377377377377
200437630361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
200437620361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
200437630361025200010001000100010001416522820357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
2004376303610252000100010001000100014075228203573763767231122000100010001000100037637611100110001000120731161137310001000377377377377377
200437630361025200010001000100010001407522837357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
200437630361025200010001000100010001407522820357376380723109200010001000100010003763761110011000100000731161137310001000377380377377377
200437630361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377

Test 2: Latency 1->2 roundtrip

Code:

  scvtf d0, w0, #3
  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)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 miss (a1)ld unit uop (a6)l1d cache writeback (a8)acc2cfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30204130032977000000130017119408254010010100200001000010020000100005006214497148027090130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000131012163212951910000100001000010100130033130033130033130033130033
30204130032974000000130017119408254010010100200001000010020000100005006214497148027090130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000131013163312951910000100001000010100130033130033130033130033130033
30204130032973000000130017119406254010010100200001000010020000100005006214497148027091130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000137312163312951910000100001000010100130033130033130033130033130033
30204130032974000000130017119408254010010100200001000010020000100005006214497148027091130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000131013163312951910000100001000010100130033130033130033130033130033
30204130032974000000130017119408254010010100200001000010020000100005006214497148027091130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000030131012163212951910000100001000010100130033130033130033130033130033
30204130032974000000130017119408254010010100200001000010020000100005006214497148027090130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000131013163212951910000100001000010100130033130071130033130033130033
30204130032973000000130017119408254010010100200001000010020000100005006214497148027091130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000131013163212957310000100001000010100130033130033130033130033130033
30204130036974000000130017119408254010010100200001000010020000100005006214497148027091130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000139112162312951910000100001000010100130033130033130033130033130033
30204130032974000000130017119408254010010100200001000010020000100005006214497148027090130013130032130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000131013163312951910000100001000010100130033130034130036130034130033
302041300329740001200130017119409254010010100200001000010020000100005006214497148028220130014130035130032125466312624030100200100002000020010000200001300321300321120201100991001010010000100010000000131012162212952010000100001000010100130033130033130033130034130033

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0032

retire uop (01)cycle (02)03l2 tlb miss data (0b)181e1f3f4f51schedule 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? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
300241300329910008813001911940845400101001020000100041020000100005062144971480052811301641300331300331254893126262300102010000200002010000200001300321300321120021109101001010000101000000013292161112951910000100001000010010130033130033130033130033130033
30024130032974000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000012701161112951910000100001000010010130033130033130033130033130033
30024130032974000013001711940825400101001020000100001020000100005062144971480052801300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000012701161112951910000100001000010010130033130033130033130033130033
300241300321018009013001711943625400101001020000100001020000100005062144971480052801300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000012702161112951910000100001000010010130033130068130033130033130033
300241300329740027013001711940825400101001020000100001020000100005062144971480052801300131300351300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000012702161112957910000100001000010010130033130033130033130033130033
30024130032974000013002511940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000012701161112951910000100001000010010130033130033130033130033130033
30024130033974000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000012701161112951910000100001000010010130033130033130033130033130033
30024130032974000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300331300321120021109101001010000101000000012701161112951910000100001000010010130033130033130035130033130033
30024130032974003013001711940825400101001020000100001020000100005062144971480052801300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000012701161112951910000100001000010010130033130033130033130033130033
30024130032974000013001711940825400101001020000100001020000100005062144971480052801300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000012701161112951910000100001000010010130033130033130033130033130033

Test 3: throughput

Count: 8

Code:

  scvtf d0, w8, #3
  scvtf d1, w8, #3
  scvtf d2, w8, #3
  scvtf d3, w8, #3
  scvtf d4, w8, #3
  scvtf d5, w8, #3
  scvtf d6, w8, #3
  scvtf d7, w8, #3
  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)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)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)9fl1d tlb miss (a1)a5ld unit uop (a6)l1d cache writeback (a8)acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfmap dispatch bubble (d6)fetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
160204267112000000002674402516010010080000800001008002080015500116895118841631266902670926709663206666416013520080020800202008002080020267092670911802011009910010080000100008000000011151171602670680000800001002671026710267102671026710
160204267092000000002669402516010010080000800001008002080015500116895118841631266902670926709663206665816013520080020800202008002080020267092670911802011009910010080000100008000000011151171602670680000800001002671026710267102671026710
160204267092000000002670302516010010080000800001008002080015500116895118841631266902670926709663206665816013520080020800202008002080020267092670911802011009910010080000100008000000011151171602670680000800001002671026710267102671026710
160204267092000000002671602516010010080000800001008002080015500116895118841631266902670926709663206665816013520080020800202008002080020267092670911802011009910010080000100008000000011151171602670680000800001002671426710267102671026710
160204267092000000002670602516010010080000800001008002080015500116895118841631266902670926709663206665816013520080020800202008002080020267092670911802011009910010080000100008000000011151171602670680000800001002671026710267102671026710
160204267092000000002669502516010010080000800001008002080015500116895118841631266902670926709663206665816013520080020800202008002080020267092670911802011009910010080000100008000000011151171602670680000800001002671026710267102671026710
1602052670920000002648826925128941603601008026080260102803968019650011795261898015126989269352705167266545681416086720080407802152028040780411270392692131802011009910010080000100208000000211151393422699480000800001002699526930269382706127052
160204268822011112264882670002516010010080000800001008002080014500116963018886961266902670926714663606666216013420080020800242008002080020267092670911802011009910010080000100008000013011151171602670680000800001002671026710267102671026710
160204267092000000002670202516010010080000800001008002080015500116895118841631266902670926709663206665816013520080020800202008002080020267092670911802011009910010080000100008000000011151171602670680000800001002671026710267102671026710
160204267092000000002670402516010010080000800001008002080015500116895118841631266902670926709663206665816013520080020800202008002080020267092670911802011009910010080000100008000000011151171602670680000800001002671026710267102671026710

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)031e1f3f4f51schedule 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)accfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
16002426714200002677422516001010800008000010800008000050116622218852761266942671426713665436694160010208000080000208000080000267132671211800211091010800001080000135020061654267108000080000102672426710267142671026714
160024267132011202669822516001010800008000010800008000050116840018843181266942671326709665636694160010208000080000208000080000267102671311800211091010800001080000135020051655267108000080000102672526715267102671126711
16002426713200002669822516001010800008000010800008000050116882718891261266942670926713665636694160010208000080000208000080000267132670911800211091010800001080000135020051663267118000080000102671526711267152683426715
160024267102001202669822516001010800008000010800008000050116810418838991266902671426713665336693160010208000080000208000080000267132671311800211091010800001080000135020031635267118000080000102672926714267142671426714
16002426713200002669402516001010800008000010800008000050116864318854241266942670926713665736693160010208000080000208000080000267092670911800211091010800001080000135020031663267108000080000102671926714267142671426710
160024267132001202669822516001010800008000010800008000050116806618825501266952670926709665736698160010208000080000208000080000267142671311800211091010800001080000135020031646267118000080000102672626714267142671026714
16002426709200002669852516001010800008000010800008000050116823418840321266942671326713665336693160010208000080000208000080000267132671311800211091010800001080000035020041663267108000080000102671026715267142671426715
160024267132001202669922516001010800008000010800008000050116835118840321266942671326713665636693160010208000080000208000080000267092670911800211091010800001080000105020031636267108000080000102671426835267132672226714
160024267132001202669822516001010800008000010800008000050116871518785101266942671326713665736693160010208000080000208000080000267132671311800211091010800001080000165020051665267108000080000102673026717267142671426714
16002426709200002669822516001010800008000010800008000050116846318820091266942671426713665336693160010208000080000208000080000267132670911800211091010800001080000105020061666267108000080000102671926714267142671426714