Apple M1 Microarchitecture Research by Dougall Johnson

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

CLZ (vector, 4S)

Test 1: uops

Code:

  clz v0.4s, v0.4s
  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)031e1f3f4e51inst 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)a8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
1004203715006116862510001000100026452102018203720371571318951000100010002037203711100110000073116111786100020382038203820382038
1004203715306116862510001000100026452102018203720371571318951000100010002037203711100110000073116111786100020382038203820382038
1004203716306116862510001000100026452112018203720371571318951000100010002037203711100110000073116111786100020382038203820382038
1004203715006116862510001000100026452102018203720371571318951000100010002037203711100110000073116111786100020382038203820382038
10042037153006116862510001000100026452102018203720371571318951000100010002037203711100110000073116111786100020382038203820382038
1004203715006116862510001000100026452102018203720371571318951000100010002037203711100110000073116111786100020382038203820382038
1004203715006116862510001000100026452102018203720371571318951000100010002037203711100110000073116111786100020382038203820382038
1004203715006116862510001000100026452102018203720371571318951000100010002037203711100110000073116111786100020382038203820382038
1004203715006116862510001000100026452102018203720371571318951000100010002037203711100110000073116111786100020382038203820382038
1004203715006116862510001000100026452102018203720371571318951000100010002037203711100110000073116111786100020382038203820382038

Test 2: Latency 1->2

Code:

  clz v0.4s, v0.4s
  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)0318191e1f3f4e51inst 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)9fa0a6a8accfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204200371500000611968625101001001000010010000500284878520018200372003718421318745101002001000020010000200372003711102011009910010010000100001371011611197910100001002003820038200382003820038
102042003715000004221968625101001001000010010000500284752120018200372003718421318745101002001000020010000200372003711102011009910010010000100002071011611197910100001002003820038200382003820038
10204200371500000611968625101001001000010010000500284752120018200372003718421318745101002001000020010000200372003711102011009910010010000100003371011611197910100001002003820038200382003820038
10204200371500000611968625101001001000010010000500284752120018200372003718421318745101002001000020010000200372003711102011009910010010000100002371011611197910100001002003820038200382003820038
10204200371500000611968625101001001000010010000500284752120018200372003718421318745101002001000020010000200372003711102011009910010010000100000371011611197910100001002003820038200382003820038
10204200371500000611968625101001001000010010000500284752120018200372003718421318745101002001000020010165200372003711102011009910010010000100000371011611197910100001002003820038200382003820038
10204200851500000611968625101001001000010010000500284752120018200372003718421318745101002001000020010000200372003711102011009910010010000100001671011611197910100001002003820038200382003820038
102042003715000006119686251010010010000100100005002847521200182003720037184213187451010020010000200100002003720037111020110099100100100001000016371011611197910100001002003820038200382003820038
10204200371500000611968625101001001000010010000500284752120018200372003718421318745101002001000020010000200372003711102011009910010010000100000371011611197910100001002003820038200382003820038
10204200371500000611968625101001001000010010000500284752120018200372003718421318745101002001000020010167200372003711102011009910010010000100002071011611197910100001002003820038200382003820038

1000 unrolls and 10 iterations

Result (median cycles for code): 2.0037

retire (01)cycle (02)03181e1f3f4e51inst 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? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10024200371500120611968625100101010000101000050284752112001820037200371844331876710010201000020100002003720037111002110910101000010200640416441978610000102003820038200382003820038
10024200371500006119686251001010100001010000502847521020018200372003718443318767100102010000201000020037200371110021109101010000102900640316341978610000102003820038200382003820038
100242003715001201061968625100101010000101000050284752102001820037200371844331876710010201000020100002003720037111002110910101000010100640316441978610000102003820038200382003820038
1002420037150000611968625100101010000101000050284752102001820037200371844331876710010201000020100002003720037111002110910101000010100640316341978610000102003820038200382003820038
1002420037150000611968625100101010000101000050284752102001820037200371844331876710010201018020100002003720037111002110910101000010000640416441978610000102003820038200382003820038
1002420037150000611968625100101010000101000050284752112001820037200371844331876710010201000020100002003720037111002110910101000010000640316431978610000102003820038200382003820038
1002420037150000611968625100221210000101000050284752112001820037200371844331876710010201000020100002003720037111002110910101000010030640316431978610000102003820038200382003820038
1002420037150000611968625100101010000101000050284752112001820037200371844331876710010201000020100002003720037111002110910101000010000640316431978610000102003820038200382003820038
1002420037150000611968625100101010000101000050284752112001820037200371844331876710163201000020100002003720037111002110910101000010030640416441978610000102003820038200382003820038
10024200841500001031968643100101010012101000050284752112001820037200371844331876710010201000020100002003720084111002110910101000010460640416441978610000102003820038200382003820085

Test 3: throughput

Count: 8

Code:

  clz v0.4s, v8.4s
  clz v1.4s, v8.4s
  clz v2.4s, v8.4s
  clz v3.4s, v8.4s
  clz v4.4s, v8.4s
  clz v5.4s, v8.4s
  clz v6.4s, v8.4s
  clz v7.4s, v8.4s
  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)03081e3f51inst 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)9fa8acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
802042006815000292580108100800081008002050064013220019200382003899776998980120200800322008013120038200381180201100991001008000010007811151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401322001920038200389977699898012020080032200800322003820038118020110099100100800001000311151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401322001920038200389977699898012020080032200800322003820038118020110099100100800001000011151180410020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401322001920038200389977699898012020080032200800322003820038118020110099100100800001000311151180160020035800001002003920039200392003920039
802042003815001229258010810080008100800205006401322001920038200389977699898012020080032200800322003820038118020110099100100800001000311151180160020035800001002003920039200392003920039
802042003815000292580108100800081008002050064013220019200382003899776998980120200800322008003220038200381180201100991001008000010030011151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401322001920038200389977699898012020080032200800322003820038118020110099100100800001001311151180160020035800001002003920039200392003920039
80204200381520029258010810080008100800205006401322001920038200389977699898012020080032200800322003820038118020110099100100800001001611151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401322001920038200389977699898012020080032200800322003820038118020110099100100800001000311151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401322001920038200389977699898012020080032200800322003820038118020110099100100800001000011151180160020035800001002003920039200392003920039

1000 unrolls and 10 iterations

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

retire (01)cycle (02)030407090a0b0e18191e1f3f51inst 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)9fa0a1a6a7a8a9acc2cficache miss (d3)itlb miss (d4)d5d6ddinst fetch restart (de)e0? int output thing (e9)eb? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8002420051150000002000038272580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100000000050210114161017200350080000102003920050200392003920039
80024200381501000000000392580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100000000050210117161717200350080000102003920066200392003920039
80024200381501000000000704258001010800001080000506400000200192003820038999631001880010208000020800002003820038118002110910108000010000000905021011716916200350080000102003920050200392003920039
8002420038149100000000039258001010803751080000506400000200192003820038999631001880010208000020800002003820038118002110910108000010000020305021018161717200350080000102003920050200392003920039
80024200381491000000000392580010108000010800005064000012001920038200389996310018800102080000208000020038200381180021109101080000100000000050210114161714200350080000102003920050200392003920039
8002420038150100000000039258001010800001080000506400000200192003820038999631001880010208000020800002003820038118002110910108000010000000005021011716178200350080000102003920050200392003920039
80024200381501000000000392580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100000000050210117161017200350080000102003920050200392003920039
80024200381501000000000392580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100000100050210117161017200350080000102003920050200392003920039
8002420038150100000000060258001010800001080000506400000200192003820038999631001880010208000020800002003820038118002110910108000010000010305021019161714200830080000102003920050200392003920039
80024200381501000000000392580010108000010800005064000002001920038200389996310018800102080000208000020038200381180021109101080000100000000050210117161717200350080000102003920066200392003920039