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, D from W)

Test 1: uops

Code:

  scvtf d0, 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)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)60696d6emap 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
2004376303610252000100010001000100014075228201357376376723109200010001000100010003793761110011000100000731161137310001000377377377377377
2004376303640252000100010001000100014075228201357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
2004376203610252000100010001000100014075228201357376376723109200010001000100010003763761110011000100003731161137310001000377377377377377
2004376303610252000100010001000100014075228201357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
2004376303610252000100010001000100014075228201357376376723109200010001000100010003763761110011000100010731161137310001000377377377377378
2004376203612252000100010001000100014075228201357379376723109200010001000100010003763761110011000100000731161137310001000377377377377380
2004376303610252000100010001000100014075228201357376376723109200010001000100010003893761110011000100000731161137310001000377377377377377
2004376333610252000100010001000100014075228201357376376723109200010001000100010003763761110011000100000731161137310001000380377377377377
2004376203640252000100010001000100014075228201357376376723109200010001000100010003763761110011000100000731161137610001000377377377377377
2004376303610252000100010001000100014075228201357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377

Test 2: Latency 1->2 roundtrip

Code:

  scvtf d0, 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)03191e1f3f4f51schedule 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)a9accfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30204130032974039013001711941225401001010020000100001002000010000500621454514803054113001313046713011712558231262403010020010000200002001006420000130036130032112020110099100101001000010010000000131014162212952010000100001000010100130033130033130033130033130033
30204130034974012013001711940825401001010220000100041172000010098500622229314802709113008213003313003312546631263013042920410000207352021006120489130032130033312020110099100101001000010010000003131012162212951910000100001000010100130033130033130033130033130034
3020413003297400013001711941025401001010020003100001002000010000500621449714802824113001413003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010010000000131012162212952110000100001000010100130033130033130033130033130033
3020413003297409013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010010000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400013001711940825401001010020000100001002000010000500621449714802709113001613003213044712546631262403010020010000200002001000020000130032130032112020110099100101001000010010000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010010000000131012162212951910000100001000010100130033130033130033130033130033
30204130032973012013001711940825401001010020000100001002000010000500621449714802709113001413003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010010000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297300013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010010000000133612162212951910000100001000010100130033130033130033130033130033
3020413003297309013001711940825401001010020000100001002000010000500621449714802709113001613003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010010000000131012162212952210000100001000010100130033130033130033130033130033
3020413003297400013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010010000000131012162212951910000100001000010100130033130033130033130036130033

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0032

retire uop (01)cycle (02)03l1i tlb fill (04)mmu 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)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)st unit uop (a7)l1d cache writeback (a8)a9acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30024130032974000012013001711940825400101001020000100001020000100005062144971480052801300141300351300331254893126262300102010000200002010000200001300331300321120021109101001010000100100000103012705162212951910000100001000010010130035130035130033130033130033
3002413003297400000013001711940825400101001020000100001020000100005062144971480052801300161300321300371254893126263300102010000200002010000200001300321300321120021109101001010000100100000100012702162312951910000100001000010010130033130033130035130033130033
30024130033974000012013001911940925400101001020000100001020000100005062144971480052801300131300391300321254903126263300102010000200002010000200001300321300321120021109101001010000100100000103012702162212951910000100001000010010130033130033130033130036130033
30024130036973000012013001711940825400101001020000100001020000100005062144971480052801300131300321300321254903126262300102010000200002010000200001300321300321120021109101001010000100100000103012702162112957310000100001000010010130033130033130033130035130033
30024130032974000012013001711940925400101001020000100001020000100005062145451480052811300131300321300351254893126262300102010000200002010000200001300321300321120021109101001010000100100000103212703165312951910000100001000010010130033130033130033130033130034
30024130032974000012013001711940825400101001020000100001020000100005062145451480052811300131300321300321254893126262300102010000200002010000200001300331300321120021109101001010000100100000103012702164312952210000100001000010010130033130033130033130033130033
30024130035974000012013001711940825400101001020000100001020000100005062146411480052801300131300341300321254893126262300102010000200002010000200001300321300321120021109101001010000100100000100012704162112951910000100001000010010130033130033130033130033130033
3002413003297400000013001711940825400101001020000100001020000100005062144971480052801300131300321300321254893126264300102010000200002010000200001300321300321120021109101001010000100100010103012702162312951910000100001000010010130033130033130035130033130033
30024130032974000012013001711940925400101001020000100001020000100005062144971480075801300151300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100100000006012702164312952010000100001000010010130033130033130033130033130033
3002413003297400000013001711940825400101001020000100001020000100005062144971480052801300131300321300321254893126263300102010000200002010000200001300321300321120021109101001010000100100000000212704164412951910000100001000010010130033130033130033130033130033

Test 3: throughput

Count: 8

Code:

  scvtf d0, w8
  scvtf d1, w8
  scvtf d2, w8
  scvtf d3, w8
  scvtf d4, w8
  scvtf d5, w8
  scvtf d6, w8
  scvtf d7, 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)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)acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)daddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
160204267092001202669812516010010080000800001008002080015500116974618809360267092670926710663666662160135200800248002020080024800242671326713118020110099100100800001008000010011151172160122671080000800001002671526714267142671426714
160204267092001202669822516010010080000800001008002080016500116895118841630266942671326713663666662160134200800208002020080020800202671426713118020110099100100800001008000013011151171160122671180000800001002671426710267142671426714
160204267132001202669822516010010080000800001008002080015500116973418839500267002671326713663666662160135200800208002020080020800202670926709118020110099100100800001008000013011151173160232671080000800001002671026710267142671426714
160204267092001202669822516010010080000800001008002080016500116895118823350266942671326713663666662160135200800208002020080020800202670926709118020110099100100800001008000013011151172160212670680000800001002671426715267102671026714
160204267132001202669822516010010080000800001008002080015500117023818827800267002671326713663666658160135200800208002020080024800242671326713118020110099100100800001008000010011151172160212671080000800001002671426714267142671026714
16020426714200002669432516010010080000800001008002080014500116966718838530266902671326713663666662160135200800208002420080020800202671426713118020110099100100800001008000010011151172160222671080000800001002671526714267142671026715
1602042670920012026694025160100100800008000010080024800145001168931188416502669426713267136632256662160135200800208002020080020800202670926709118020110099100100800001008000013011151172160212671080000800001002671526714267142671426715
160204267132001202669722516010010080000800001008002080015500116827818842050266942671026714663666662160135200800208002020080020800242671326713118020110099100100800001008000013011151172160222671080000800001002671426710267102671426715
160204267132001202669832516010010080000800001008002080015500116071318884500266942670926709663666659160134200800208002020080020800202670926713118020110099100100800001008000000011151172160222671180000800001002671426714267142671426714
160204267132001202669422516010010080000800001008002080014500116812618816130266992671426713663266661160133200800208002020080024800202671326709118020110099100100800001008000013011151172160222671080000800001002671026714267142671526710

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)031e3f4f51schedule 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 access (a0)l1d tlb miss (a1)a5ld unit uop (a6)l1d cache writeback (a8)acc2cfd5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
16002426710200026694025160010108000080000108000080000501168880188403212673626709267096653036689160010208000080000208000080000267092670911800211091010800001000080000000502016161314267068000080000102671026710267102671026710
160024267092001526694025160010108000080000108000080000501168880188403212669526709267206653036689160010208000080000208000080000268152670911800211091010800001000080000400502015161414267068000080000102671026710267102671026710
16002426709199026694025160010108000080000108000080000501168880188403202669826709267096665036689160010208000080000208000080000267092670911800211091010800001000080000000502013161311267068000080000102671026710267102671026710
16002426709200026694025160010108000080000108000080000501168880188403202669126709267096653036689160010208000080000208000080000267092670911800211091010800001000080000000502013161314267068000080000102671026710267102671026710
1600242670920002669402516001010800008000010800008000050116888018840320267002670926709665303669216001020800008000020800008000026709267091180021109101080000100008000000050201216149267068000080000102671026710267102671026710
1600242670920002669402516001010800008000010800008000050116888018840320267012670926709665303668916001020800008000020800008000026709267091180021109101080000100008000000050208161412267068000080000102671026710267102671026710
16002426709200026694025160010108000080000108000080000501168880188403212670126709267096653036689160010208000080000208000080000267092670911800211091010800001000080000000502016161313267068000080000102671026710267102671026710
16002426709200026694025160010108000080000108000080000501168880188403202669926716267136653036689160010208000080000208000080000267092670911800211091010800001000080000000502012161111267068000080000102671026710267102671026710
16002426709200026694025160010108000080000108000080000501168880188403202669926712267156653036689160010208000080000208000080000267092670911800211091010800001000080000000502012161414267068000080000102671026710267102671026710
1600242670920002669402516001010800008000010800008000050116888018840321267012670926709665303668916001020800008000020800008000026711267091180021109101080000100008000000050201316812267068000080000102671026714267102671026710