Apple M1 Microarchitecture Research by Dougall Johnson

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

SXTL2 (8H)

Test 1: uops

Code:

  sxtl2 v0.8h, v0.16b
  movi v0.16b, 1
  movi v1.16b, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 0.000

Load/store unit issues: 0.000

SIMD/FP unit issues: 1.000

retire (01)cycle (02)03080918191e1f3a3f4e51inst issue (52)~issue fp/simd (54)~dispatch fp/simd (57)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op fp/simd (7e)~map lookup fp/simd (81)8283pipeline redirect (84)85inst all (8c)inst neon or fp (9a)a0a6a8acc2cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
1004203715000000017416862510001000100026452112018203720371571318951000100010002037203711100110000000073116111786100020382038203820382038
100420371500000006116862510001000100026452112018203720371571318951000100010002037203711100110000000073116111786100020382038203820382038
1004203715000000010316862510001000100026452112018203720371571318951000100010002037203711100110000000073116111786100020382038203820382038
100420371500000006116862510001000100026452112018203720371571318951000100010002037203711100110000000073116111786100020382038203820382038
1004203715000012006116862510001000100026452112018203720371571318951000100010002037203711100110000000073116111786100020852038203820382038
100420371600000006116862510001000100026452112018203720371571318951000100010002037203721100110000000073116111786100020382038203820382038
100420371600000006116862510001000100026452112018203720371571318951000100010002037203711100110000000073116111786100020382038203820382038
100420371500000006116862510001000100026452112018203720371571318951000100010002037203711100110000000073116111786100020382038203820382038
100420371500000006116862510001000100026452112018203720371571318951000100010002037203711100110000000073124111786100020382038203820382038
1004203715000008806116862510001000100026452112018203720371571318951000100010002037203711100110000000073116111786100020382038203820382038

Test 2: Latency 1->2

Code:

  sxtl2 v0.8h, v0.16b
  movi v0.16b, 1
  movi v1.16b, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 2.0037

retire (01)cycle (02)030818191e1f3f4e51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~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)9fa0a1a8a9acc2cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
102042003715000000611968625101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038
102042003715000000611968646101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038
102042003715000000611968625101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038
102042003715000000611968625101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038
102042003715000000611968625101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038
1020420037150000002161968625101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038
102042003715000000611968625101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038
102042003715000000611968625101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038
102042003715000000611968625101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038
102042003715000000611968625101001001000010010000500284752112001820037200371842131874510100200100002001000020037200371110201100991001001000010000000071011611197910100001002003820038200382003820038

1000 unrolls and 10 iterations

Result (median cycles for code): 2.0037

retire (01)cycle (02)0307080918191e1f3f4e51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~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)9fa8acc2cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1002420037150000002406119686251001012100001210000502847521120018200372003718443318767100122010000201000020037200371110021109101010000100006442162219786010000102003820038200382003820038
100242003715000000006119686251001010100001010000502847521120018200372003718443318767100102010000201000020037200371110021109101010000100006402162219786010000102003820038200382003820038
100242003715000000006119686251001010100001010000502847521120018200372003718443318767100102010000201000020037200371110021109101010000100006402162219786010000102003820038200382003820038
100242003715010000006119686251001010100001010000502847521120018200372003718443318767100102010000201000020037200371110021109101010000100006402162219786010000102003820038200382003820038
100242003715000000006119686251001010100001010000502847521120018200372003718443318767100102010000201000020037200371110021109101010000100006402162219786010000102003820038200382003820038
100242003715000000006119686251001010100001210000602847521120018200372003718443318767100102010000201000020037200371110021109101010000100006402162219786010000102003820038200382003820038
1002420037150000003006119686251001212100001210000602850049120018200372003718443318767100102010000201000020037200371110021109101010000100006402162219786010000102003820038200382003820038
100242003715000000006119686251001010100001010000502847521120018200372003718443318767100122010000201000020037200371110021109101010000100006402162219786010000102003820038200382003820038
100242003715000000006119686251001010100001010000502847521120018200372003718443318767100102010000201000020037200371110021109101010000100006403162219786210000102003820038200382003820038
100242003715000000006119686251001010100001010000502847521120018200372003718443318767100102010000201000020037200371110021109101010000100006402162219786010000102003820038200382003820038

Test 3: throughput

Count: 8

Code:

  sxtl2 v0.8h, v8.16b
  sxtl2 v1.8h, v8.16b
  sxtl2 v2.8h, v8.16b
  sxtl2 v3.8h, v8.16b
  sxtl2 v4.8h, v8.16b
  sxtl2 v5.8h, v8.16b
  sxtl2 v6.8h, v8.16b
  sxtl2 v7.8h, v8.16b
  movi v8.16b, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.2505

retire (01)cycle (02)03070a181e1f3f51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~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)9fc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
802042005715011000292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151182161120035800001002003920039200392003920039
802042003815011000292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151181161120035800001002003920039200392003920039
802042003815011000292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151181161120035800001002003920039200392003920039
80204200381501101620292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151181161120035800001002003920039200392003920039
802042003815011000292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151181161120035800001002003920039200392003920039
8020420038150110150292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151181161120035800001002003920039200392003920039
802042003815011090292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151181161120035800001002003920039200392003920039
802042003815011090292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151181161120035800001002003920039200392003920039
802042003815011000292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151181161120035800001002003920039200392003920039
802042003815011000292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010011151181161120035800001002003920039200392003920039

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.2505

retire (01)cycle (02)0307080b18191e1f3f51inst issue (52)~issue int (53)~issue fp/simd (54)~dispatch int (56)~dispatch fp/simd (57)huge thing int (59)huge thing fp/simd (5b)60696d6edispatch stall (70)scheduler rewind (75)scheduler stall (76)~dispatch op (78)~map op int (7c)~map op fp/simd (7e)~map lookup int (7f)~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)9fa0a8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80024200391500000000392580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100005020716362003580000102003920039200392003920039
80024200381500000090392580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100005020216622003580000102003920039200392003920039
80024200381490000000392580010108000010800005064000012001920038200389996310018801242080000208000020038200381180021109101080000100005020616262003580000102003920039200392003920039
80024200381500000000392580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100005020216262003580000102003920039200392003920039
80024200381500000000392580010108000010800005064000012001920038200389996310018800102080000208000020038200381180021109101080000100005020316622003580000102003920039200392003920039
80024200381500000000392580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100005020216222003580000102003920039200392003920039
80024200381500000000392580010108000010800005064000012001920038200389996310018800102080000208000020038200381180021109101080000100005020216222003580000102003920039200392003920039
80024200381500000000392580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100005020216222003580000102003920039200392003920039
80024200381500000000392580010108000010800005064000012001920038200389996310018800102080000208000020038200381180021109101080000100005020216232003580000102003920039200392003920039
80024200381500000000672580010108000010800005064000012001920038200389996310018800102080000208000020038200381180021109101080000100005020616262003580000102003920039200392003920039