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 X)

Test 1: uops

Code:

  scvtf d0, x0, #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
200437630365025200010001000100010001407522820357376380723109200010001000100010003763761110011000100000731161137310001000377377377377377
200437630361025200010001000100010001407522869357376376723109200010001000100010003763761110011000100010731161137310001000377377379377377
200437930361025200010001000100010001407522820357376376753109200010001000100010003763771110011000100000731161137310001000377377377377377
200437620361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
200437630361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
200437620361025200010001000100010001407522820357376376733109200010001000100010003763761110011000100000731161137610001000377377377377377
200438030361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
2004379203610252000100010001000100014075228203663763767231092000100010001000100037637611100110001000012731161137310001000378377377377377
200437630361025200010001000100010001407522820357376376723109200010001000100010003763761110011000100000731161137310001000377377377377377
200437639361025200010001000100010001407522820357376376723113200010001000100010003793761110011000100000731161137310001000377377377377377

Test 2: Latency 1->2 roundtrip

Code:

  scvtf d0, x0, #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)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)ld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acc2branch cond mispred nonspec (c5)cfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
3020413003297400000001300171194082540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400000001300171194082540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400000001300171194082540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000010000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400000001300181194082540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400000001300171194082540100101002000010000100200001000050062144971480270901300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000000000131012162212951910000100001000010100130033130033130033130033130033
3020413003797400009001300171194082540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000000300131012162212951910000100001000010100130033130033130033130033130033
3020413003297400000001300171194112540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400000001300171194082540100101002000010000100200001000050062144971480270911300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400000001300171194082540100101002000010000100200001000050062144971480270901300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000000000131012162212951910000100001000010100130033130033130033130033130033
3020413003297400000001300171194082540100101002000010000100200001000050062144971480270901300131300321300321254663126240301002001000020000200100002000013003213003211202011009910010100100001000010000000000131012162212951910000100001000010100130033130033130033130033130033

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)191e1f3f4f51schedule 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)accdcfd5map dispatch bubble (d6)daddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
3002413003397400012013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126265300102010000200002010000200001300321300321120021109101001010000104010000130127011601112959510000100001000010010130033130033130033130036130033
30024130032974000120130017119409254001010010200001000010200001000050621449714800528113001313003213003212548914126262300102010000200002010000200001300321300321120021109101001010000100010000000127021601112957410000100001000010010130033130033130033130034130033
300241300329740000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100010000030127011601112951910000100001000010010130033130033130033130033130033
300241300329740000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000102410003000127013201112952210000100001000010010130035130033130033130034130033
300241300329730000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100010000000127011601112951910000100001000010010130033130033130033130033130033
3002413003297300069013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100010000000127011602112951910000100001000010010130033130033130033130033130033
300241300329740000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126263300102010000200002010000200001300321300321120021109101001010000100010000000127011601112951910000100001000010010130033130033130033130033130033
300241300329740000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100010000000127021601112951910000100001000010010130033130033130033130033130033
300241300329740000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100010000030127011601112951910000100001000010010130033130033130033130033130033
300241300329740000013001711940825400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100010000000127011601112951910000100001000010010130033130033130033130033130033

Test 3: throughput

Count: 8

Code:

  scvtf d0, x8, #3
  scvtf d1, x8, #3
  scvtf d2, x8, #3
  scvtf d3, x8, #3
  scvtf d4, x8, #3
  scvtf d5, x8, #3
  scvtf d6, x8, #3
  scvtf d7, x8, #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 access (a0)l1d tlb miss (a1)a5ld unit uop (a6)l1d cache writeback (a8)acc2branch 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
1602042670920000001202669422516010010080000800001008002080015500117028218823911266902671326713663606666216013620080024800202008002480020267222671311802011009910010080000100000800000301115117016002670680000800001002671426714267152671426710
1602042671320000001202669402516010010080000800001008002080015500116895118841631266942670926709663606666216013620080024800202008002080020267132671311802011009910010080000100000800001301115117016002670680000800001002671526715267102671426710
1602042671320000001202669822516010010080000800001008002080015500116895118848330266942670926713663606665816013420080024800202008002480020267092670911802011009910010080000100000800001301115117016002671080000800001002671526714267142671026710
1602042671320000001202669802516010010080000800001008002080015500117571218817190266942670926713663206665816013520080020804032008002080020267192687811802011009910010080000100000800001301115117016002671080000800001002671426714267102671526714
1602042670920000001202669822516010010080000800001008002080015500116829918841631266902670926713663206665816013520080020800202008002080020267132671311802011009910010080000100000800001301115117016002671080000800001002671426710267142671026710
160204267142000000002669822516010010080000800001008002080015500116895118814120266902670926713663606665816013520080024800242008002080020267092671311802011009910010080000100000800001301115117016002671080000800001002671426714267102671526714
1602042671320000001202669412516010010080000800001008002080014500116895118977840266942671326714663206666216013620080020800202008002480020267212670911802011009910010080000100000800000001115117016002671080000800001002671026715267142671426714
1602042670920000001202669802516010010080000800001008002080015500117765918840340266942671326709663206665816013520080024800202008002080024267102671311802011009910010080000100000800001301115117016002670680000800001002671426710267102671426714
1602042671320000001202669432516010010080000800001008002080015500117542718787720266902670926713663206665816013420080595800202008002080020267152671311802011009910010080000100000800000301115117016002670780000800001002671426710267142671426710
160204267092000000002669832516010010080000800001008002080015500116854018842150266942671426714663206666216013520080020800202008002080020267172670911802011009910010080000100000800001001115117016002671080000800001002671826724267142672426721

1000 unrolls and 10 iterations

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

retire uop (01)cycle (02)03191e3f4f51schedule 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)9fa5ld unit uop (a6)l1d cache writeback (a8)accfd0d2l1i cache miss demand (d3)d5map dispatch bubble (d6)ddfetch restart (de)e0? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
16002426709207002669402516001010800008000010800008000050116888018840320266902670926709665336689160010208000080000208000080000267252676811800211091010800001008000000502000061632267068000080000102671026710267102671026710
16002426709200002669402516001010800008000010800008000050116888018840320266902670926709665336689160010208000080000208000080000268022670911800211091010800001008000000502000021622267068000080000102671026710267102671026710
16002426709200002669402516001010800008000010800008000050116888018840320266902670926709665536689160010208000080000208000080000267142670921800211091010800001008000000502000021663267068000080000102690126885267142671026710
16002426709200002669402516001010800008000010800008000050116888018840320266902670926709665336689160010208000080000208000080000267182671211800211091010800001008000000502000021622267068000080000102671026710267102671026710
16002426709200002669402516001010800008000010800008000050116888018840320266902670926709665336689160010208000080000208000080000268242671111800211091010800001008000000502000061622267068000080000102671026710267102671026710
16002426709200002669402516001010800008000010800008000050116888018840320266902670926709665336689160010208000080000208000080000267152682711800211091010800001008000000502000021662267168000080000102671026710267102671026710
16002426709200002669432516001010800008000010800008000050116888018840320266902670926709665336689160010208000080000208000080000267092670911800211091010800001008000000502000021636267068000080000102671026710267102671026710
16002426709200002669402516001010800008000010800008000050116888018840320266902670926709665336689160010208000080000208000080000267092670911800211091010800001008000000502000021622267068000080000102671026710267102671026710
16002426709200002669402516001010800008000010800008000050116888018840321266902670926709665336689160010208000080000208000080000267092670911800211091010800001008000000502000021666267088000080000102671026710267102671026710
16002426709200002669402516001010800008000010800008000050116888018840320266902670926709665336689160010208000080000208000080000267092670911800211091010800001008000000502000061666267118000080000102671026710267142671326710