Apple M1 Microarchitecture Research by Dougall Johnson

Firestorm: Overview | Base Instructions | SIMD and FP Instructions
Icestorm:  Overview | Base Instructions | SIMD and FP Instructions

UCVTF (scalar, fixed-point, S from X)

Test 1: uops

Code:

  ucvtf s0, 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 (01)cycle (02)031e3f4f51inst issue (52)~issue fp/simd (54)~issue ld/st (55)~dispatch fp/simd (57)~dispatch ld/st (58)huge thing ld/st (5a)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op ld/st (7d)~map op fp/simd (7e)~map lookup ld/st (80)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst neon or fp (9a)a5a6a8accfd5d6ddinst fetch restart (de)e0ld/st retires (ed)? fp/simd (ee)f5f6f7f8fd
20043763036102520001000100010001000140752282013573763767231092000100010001000100037637611100110000100000731161137310001000377377377377377
20043763036132520001000100010001000140752282013573763767231092000100010001000100037637611100110000100000731161137310001000377377377377377
20043763036102520001000100010001000140752282013573763767231092000100010001000100037637611100110000100000731161137310001000377377377377377
20043763036102520001000100010001000140752282003573763767231092000100010001000100037637611100110000100000731161137310001000377377377377377
20043763036102520001000100010001000140752282003573763767231092000100010001000100037637611100110000100000731161137310001000377377377377377
20043762036102520001000100010001000140752282013573763767231092000100010001000100037637611100110000100000731161137310001000377377377378377
20043763036102520001000100010001000140752282003573763767231092000100010001000100037637611100110000100020731161137310001000377377377377382
20043762036202520001000100010001000140752282013573763767231092000100010001000100037637611100110000100000731161137310001000377377377377377
20043763036102520001000100010001000140752282013573763767231092000100010001000100037637611100110000100000731161137310001000377377381377377
20043763036102520001000100010001000140752282013573763767231092000100010001000100037637611100110000100000731161137310001000377377377377377

Test 2: Latency 1->2 roundtrip

Code:

  ucvtf s0, 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 (01)cycle (02)03080918191e1f3a3f4f51inst issue (52)~issue int (53)~issue fp/simd (54)~issue ld/st (55)~dispatch int (56)~dispatch fp/simd (57)~dispatch ld/st (58)huge thing int (59)huge thing ld/st (5a)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op ld/st (7d)~map op fp/simd (7e)~map lookup int (7f)~map lookup ld/st (80)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa0a1a6a8a9acc5branch mispredict (cb)cdcfd0d5d6ddinst fetch restart (de)e0? int output thing (e9)ebld/st retires (ed)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
302041301099740000660013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010000100000000001310121633129519100000100001000010100130033130033130033130033130033
30204130032974000000013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010000100000000001310131633129520100000100001000010100130033130033130033130033130033
30204130032974000000013001711940825401371010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010000100000000001310121632129519100000100001000010100130033130033130033130033130033
30204130032974000000013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002061006120000130032130032112020110099100101001000010000100000000001310121623129519100000100001000010100130033130372130033130033130033
30204130032973000000013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010000100000000001310131632129519100000100001000010100130033130037130033130033130033
30204130032974000000013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010000100000000001310131622129519100000100001000010100130033130033130033130034130033
30204130032975000000013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010000100000000001310121623129519100000100001000010100130033130033130033130033130033
30204130032974000000013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010000100000000001310121632129519100000100001000010100130033130033130033130033130033
30204130032974000090013001711940825401001010020000100001002000010000500621449714802709113001313003513003212546631262443010020010000200002001000020000130032130032112020110099100101001000010000100000000001310131633129519100000100001000010100130034130033130033130036130034
30204130032974000000013001711940825401001010020000100001002000010000500621449714802709113001313003213003212546631262403010020010000200002001000020000130032130032112020110099100101001000010000100000000001310131632129519100000100001000010100130033130033130033130033130033

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0032

retire (01)cycle (02)0308191e1f3f4f51inst issue (52)~issue int (53)~issue fp/simd (54)~issue ld/st (55)~dispatch int (56)~dispatch fp/simd (57)~dispatch ld/st (58)huge thing int (59)huge thing ld/st (5a)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op ld/st (7d)~map op fp/simd (7e)~map lookup int (7f)~map lookup ld/st (80)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa1a6a8a9acc2cdcfd5d6ddinst fetch restart (de)e0? int output thing (e9)ld/st retires (ed)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
30024130032974000013002311940825400101001020000100001020000100005062144971480052811300131300321300321254903126262300102010000200002010000200001300351300321120021109101001010000100100001000012706494212952210000100001000010010130381130200130101130229130033
300241300329740000130017119409254001010010200001000010200001000050621449714800528013001613003213003212549031262623001020100002000020100002000013003213003211200211091010010100001001000000169890012703163312952210000100001000010010130033130033130092130047130033
30024130032973000013001711948425400101001020000100001020000100005062171101480052811301091300321300321254893126262300102010000200002010000200001300321300411120021109101001010000100100000000012703173312951910000100001000010010130033130033130033130075130033
30024130032974000013001711941125400101001020000100001020000100005062144971480052801300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100100000000012703163312951910000100001000010010130033130033130073130062130033
30024130032995000013001711941025400101001020000100001020000100005062144971480052811300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100100000000012702164312951910000100001000010010130033130033130033130150130033
30024130032974009013001711941125400101001020000100001020000100005062144971480052801300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100100000000012703163312951910000100001000010010130033130033130033130101130033
30024130032974000013001711947025400101001020009100001020000100005062144971480052801300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100100000000012703163312951910000100001000010010130033130034130082130046130033
300241300329740027013001711941825400101001020000100001020000100005062144971480052801300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100100000000012702163312951910000100001000010010130033130033130033130090130033
30024130032974000013001711941525400101001020000100001020000100005062145451480052801300131300321300321254893126262300102010000200002010000200001300321300321120021109101001010000100100000000012703163312951910000100001000010010130075130034130033130156130033
30024130032974000013001711940925400101001020000100001020000100005062144971480052801300131300321300331254893126262300102010000200002010000200001300321300321120021109101001010000100100000000012703163312951910000100001000010010130118130037130035130033130033

Test 3: throughput

Count: 8

Code:

  ucvtf s0, x8, #3
  ucvtf s1, x8, #3
  ucvtf s2, x8, #3
  ucvtf s3, x8, #3
  ucvtf s4, x8, #3
  ucvtf s5, x8, #3
  ucvtf s6, x8, #3
  ucvtf s7, 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 (01)cycle (02)031e3a3f4f51inst issue (52)~issue int (53)~issue fp/simd (54)~issue ld/st (55)~dispatch int (56)~dispatch fp/simd (57)~dispatch ld/st (58)huge thing int (59)huge thing ld/st (5a)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op ld/st (7d)~map op fp/simd (7e)~map lookup int (7f)~map lookup ld/st (80)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa6a8acc5branch mispredict (cb)cdcfd5d6dde0? int output thing (e9)ld/st retires (ed)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
160204267112070026702025160100100800008000010080020800155001168951188692312669026709267096632666581601362008002080020200800208002026709267091180201100991001008000010080000001115117016026706080000800001002671126712267102671526710
160204267092070026697025160100100800008000010080020800155001168951188416312669026709267096632666581601352008002080020200800208002026709267091180201100991001008000010080000001115117016026706280000800001002671026710267102671026710
160204267092070026716025160100100800008000010080020800155001168951188416312669026709267096632666581601352008002080020200800208002026709267091180201100991001008000010080000001115117016026706080000800001002671026710267102671026710
160204267092070026707025160100100800008000010080020800155001168951188416312669026709267096632666581601352008002080020200800208002026709267091180201100991001008000010080000001115117016026706080000800001002671026710267102671026714
1602042670920712026797025160100100800008000010080020800155001168951187292412669026709267096632666581601352008002080020200800208002026709267091180201100991001008000010080000001115117016026706080000800001002671026710267102671026710
160204267092070026700025160100100800008000010080020800155001168951188416312669026709267096632666581601352008002080020200800208002026709267091180201100991001008000010080000001115117016026706080000800001002671026710267102671026710
160204267092070026698025160100100800008000010080020800155001168951188416312669026709267096636666581601352008002080020200800208002026709267091180201100991001008000010080000001115117016026706080000800001002671026710267102671026710
160204267092070026704025160100100800008000010080020800155001168951188416312669026709267096632666581601352008002080020200800208002026709267091180201100991001008000010080000001115117016026706080000800001002671026710267142671026710
160204267092070026710025160100100800008000010080020800155001168951188416312669026709267096632666581601352008002080020200800208002026709267101180201100991001008000010080000001115117016026706080000800001002671026710267102671026710
160204267092070026716025160100100800008000010080020800155001168951188416312669026713267096636666581601352008002080020200800208002026709267091180201100991001008000010080000001115117016026711080000800001002671026710267102671026710

1000 unrolls and 10 iterations

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

retire (01)cycle (02)03080918191e1f3f4f51inst issue (52)~issue int (53)~issue fp/simd (54)~issue ld/st (55)~dispatch int (56)~dispatch fp/simd (57)~dispatch ld/st (58)huge thing int (59)huge thing ld/st (5a)huge thing fp/simd (5b)60696d6edispatch stall (70)72scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op ld/st (7d)~map op fp/simd (7e)~map lookup int (7f)~map lookup ld/st (80)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst b.cc (94)inst integer (97)inst neon or fp (9a)9fa0a1a6a8a9acbranch mispredict (cb)cfd5d6d9ddinst fetch restart (de)e0? int output thing (e9)ld/st retires (ed)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
160024267092000000002669402516001010800008000010800008000050116888018840321266902670926709665303703716001020800008000020800008000026709267091180021109101080000100080000000050202160112670608000080000102677926722267152671026710
160024267091990000002669402516001010800008000010800008000050116888018840320266902670926709665303668916001020800008000020800008000026709267091180021109101080000100080000000050201160112671008000080000102672526714267102671026710
160024267092000000002669402516001010800008000010800008000050116888018840320267552670926709665303668916001020800008000020800008000026709267091180021109101080000100080000000050201160112670608000080000102671026710267102671026710
160024267092000000002671702516001010800008000010800008000050116888018840320266902670926709665303669516001020800008000020800008000026709267091180021109101080000100080000000050201160112670608000080000102671026710267102671026710
160024267132000000002669402516001010800008000010800008000050116902418840320266902670926709665303668916001020800008000020800008000026709267171180021109101080000100080000000050201160112670608000080000102671026710267102671026710
160024267092000000002669402516001010800008000010800008000050116888018840320266902670926716665303668916001020800008000020800008000026709267091180021109101080000100080000000050201160112670608000080000102671326718267102671026710
160024267092000000002669402516001010800008000010800008000050116888018840320266902670926709665303668916001020800008000020800008000026709267091180021109101080000100080000000050201160112670608000080000102671026710267102671026710
160024267092000000002669402516001010800008000010800008000050116888018840321266902670926709665303668916001020800008000020800008000026709267091180021109101080000100080000000050201160112670608000080000102671026710267102671026710
1600242670920000000026694025160010108000080000108000080000501168880188403202669026709267096653036689160010208000080000208000080000267092670911800211091010800001000800001600050201160112670608000080000102671026710267102671026710
160024267092000000002681502516001010800008000010800008000050116888018840320266902670926709665303668916001020800008000020800008000026709267091180021109101080000100080000000050201160112670608000080000102671026710267102671026710