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 X)

Test 1: uops

Code:

  scvtf h0, 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)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
20043762243610252000100010001000100014075228701357376376733110200010001000100010003763761110011000100000731161137310001000377377377377377
2004376393620252000100010001000100014075228201357376376723112200010001000100010003763791110011000100000731161137310001000377377377377380
2004376303610252000100010001000100014075228201357376376723109200010001000100010003763761110011000100000731161137310001000377377377381377
2004376203612252000100010001000100014075228201357376376723114200010001000100010003763761110011000100000731161137310001000377377377377377
2004376303610252000100010001000100014075230161357376376723109200010001000100010003763761110011000100010731161137310001000377377377377380
2004376303610252000100010001000100014075228201357376376723111200010001000100010003763771110011000100000731161137310001000377377377377377
2004376303610252000100010001000100014075228201357376376723128200010001000100010003763761110011000100000731161137310001000377377377377377
2004376303620252000100010001000100014075228201357376376723114200010001000100010003763761110011000100000731161137310001000377377377377377
2004376303610252000100010001000100014075229491357376376723115200010001000100010003793761110011000100000731161137410001000377377377377377
2004376303610252000100010001000100014125228201357376376723115200010001000100010003763761110011000100000731161137310001000377377377377377

Test 2: Latency 1->2 roundtrip

Code:

  scvtf h0, 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)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)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)91inst 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)a9acc2branch mispred nonspec (cb)cfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
3020413003297400001300171194472540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009901001010010000100010000030000131012162212951910000100001000010100130037130033130080130046130033
3020413003297400001300171194302540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009901001010010000100010000000000131012162212951910000100001000010100130033130036130100130071130033
3020413003297400001300171194082540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009901001010010000100010000000000131013162212951910000100001000010100130033130033130033130080130033
3020413003297400001300171194332540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009901001010010000100010000010920131012162212951910000100001000010100130033130033130033130079130033
3020413003297400001300171194082540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009901001010010000100010000000000131013162312951910000100001000010100130033130033130033130063130033
3020413003297400001300171194152540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009901001010010000100010000000000131012162212951910000100001000010100130033130033130088130063130033
3020413003297400001300171194282540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009901001010010000100010000000000131012162212951910000100001000010100130033130033130097130059130034
3020413003297400001300171194082540100101002000010000100200001000050062146411480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009901001010010000100010000000000131012162212954210000100001000010100130033130070130057130034130033
30204130032974000013001711941015040107101002000010000100203521029451162144971480270911300131305271300321255073126240301002001000020000202100002000013003213003211202011009901001010010000100210000000000131012162212951910000100001000010100130033130080130079130036130033
3020413003297400001300171194082540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009901001010010000100010000000000131012162212951910000100001000010100130075130036130034130033130033

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0032

retire uop (01)cycle (02)03l2 tlb miss data (0b)181e3f4f51schedule 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)a9acc2cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)eb? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
30024130032974001213001711940825400101001020000100001020000100005062173771480064101300151300321300331254893126262300102010000200002010000200001300361300321120021109101001010000101000010300127021611129519100000100001000010010130033130033130033130033130033
30024130034974001213001711940925400101001020000100001020000100005062144971480700511300131300321300321254903126262300102010000200002010000200001300321300321120021109101001010000101000010300127011611129519100000100001000010010130033130033130033130033130035
30024130032974001213001711940825400101001020000100001020000100005062168971480392301300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000010000127011611129519100000100001000010010130033130033130033130035130033
30024130035974001213001711940825400101001020000100001020000100005062144971480734011300141300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000010300127011621129519100000100001000010010130033130033130033130034130033
30024130032974006613001711940825400101001020000100001020000100005062172451480098311300131300321300341254893126262300102010000200002010000200001300361300331120021109101001010000101000010300127011611129519100000100001000010010130033130033130033130033130033
3002413006597400013001711940825400101001020000100001020000100005062156011480415101300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000000127011611129519100000100001000010010130033130033130033130033130033
300241300329740001300171194082540010100102000010000102000010000506214497148047310130013130032130032125489312626230010201000020000201000020000130032130032112002110910100101000010100000000012702161112951910000229100001000010010130035130033130033130033130033
3002413003297400013001711940825400101001020000100001020000100005062162251480499101300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000000127011611129519100000100001000010010130033130033130033130033130033
3002413003297400013001711940825400101001020000100001020000100005062167531480302301300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000101000000000127011611129519100000100001000010010130033130033130033130033130033
30024130032974000130021119408254001010010200001000010200001000050621449714800528013001313003213003212548931262623001020100002000020100002000013003213003211200211091010010100001010000003000127021621129520100000100001000010010130033130033130033130033130033

Test 3: throughput

Count: 8

Code:

  scvtf h0, x8
  scvtf h1, x8
  scvtf h2, x8
  scvtf h3, x8
  scvtf h4, x8
  scvtf h5, x8
  scvtf h6, x8
  scvtf h7, x8
  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)03l2 tlb miss data (0b)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)9fl1d tlb miss (a1)ld unit uop (a6)a9acbranch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
16020426716200012267113251601001008000080000100800208001450011720361884045026694267092671366366666316013520080024800202008002480020267092671311802011009910010080000100080000031115117016002671080000800001002681326743267222671526710
16020426714206012266942251601001008000080000100800208001451111689511881571026690267092670966366666016013520080024800202008002080020267092670911802011009910010080000100080000001115117016002671580000800001002671026710267102671026710
1602042670920000266940251601001008000080000100800208001550011689511884163026690267092670966326665816013520080020800202008002080020267092670911802011009910010080000100080000001115117016002670680000800001002671026710267102671026710
1602042670920000266940251601001008000080000100800208001550011689511884163026690267092670966326665816013520080020800202008002080020267092670911802011009910010080000100080000001115117016002670880000800001002671026710267102671026710
1602042670920000266940251601001008000080000100800208001550011689511884163026690267092670966326665816013520080020800202008002080024267092670911802011009910010080000100080000001115117016002670680000800001002671026710267102671026710
1602042670920000266940251601001008000080000100800208001550011689511884163026690267092670966326665816013520080024800242008002480020267092671811802011009910010080000100080000001115117016002670680000800001002671026710267102671026710
1602042670920000266940251601001008000080000100800208001550011689511884163026690267092670966326665816013520080024800202008002080020267192671611802011009910010080000100080000001115117016002670680000800001002671026710267102671026710
1602042670920000266940251601001008000080000100800208001550011689511884163026690267092670966326665816013520080020800202008002080020267132671511802011009910010080000100080000001115117016002670680000800001002671026710267102671026710
1602042670920000266940251601001008000080000100800208001550011689511884163126690267092670966326684016013420080020800202008002080020267112678711802011009910010080000100080000001115117016002670680000800001002671026710267102671026710
1602042670920000266940251601001008000080000100800208001550011689511884163026690267092670966326665816013520080020800202008002080020267152681411802011009910010080000100080000001115117016002670680000800001002671026710267102671026710

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)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)st unit uop (a7)l1d cache writeback (a8)a9acc2cfd5map dispatch bubble (d6)dbddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1600242671120002669402516001010800008000010800008000050116888018840321266902670926709665336689160010208000080000208000080000267182671711800211091010800001000800000000050201916088267068000080000102671026710267102671026710
160024267092000266948251600101080000800001080000800005011688801884032126690267092670966533668916001020800008000020800008000026709267091180021109101080000100080000000005020516088267088000080000102696626727267202671526710
160024267092000266940251600101080000800001080000800005011688801884032126690267092671066533668916001020800008000020800008000026709267091180021109101080000100080000000005020916047267068000080000102696426718267202671926710
1600242670919902669402516001010800008000010800008000050116888018840321266902670926709665336689160010208000080000208000080000267092670911800211091010800001000800000300050201016096267068000080000102696926727267202672026710
1600242670920002669402516001010800008000010800008000050116888018840321266902670926709665336689160010208000080000208000080000267092670911800211091010800001000800000000050205160913267068000080000102680326717268832671326710
160024267092000266943251600101080000800001080000800005011688801884032126690267092670966533668916001020800008000020800008000026709267131180021109101080000100080000000305020616068267068000080000102695726719267982671826712
160024267092000266940251600101080000800001080000800005011688801884032126690267092670966533668916001020800008000020800008000026709267091180021109101080000100080000000005020616058267068000080000102680426716268092671226710
1600242670920002669452516001010800008000010800008000050116888018840321266902670926709665336689160010208000080000208000080000267092670911800211091010800001000800000000050201016057267068000080000102697826727267212672026710
1600242670920002669442516001010800008000010800008000050116888018840321266902670926709665336689160010208000080000208000080000267092670911800211091010800001000801320000050209160109267068000080000102699226854267202672126710
160024267092000266940251600101080000800001080000800005011688801884032126690267092670966533668916001020800008000020800008000026709267091180021109101080000100080000000005020616078267068000080000102681726718268612671026710