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, 16B)

Test 1: uops

Code:

  clz v0.16b, 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)030b1e3f4e51inst 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)a8cfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
100420371500611686251000100010002645210201820372037157131895100010001000203720371110011000073116111786100020382038203820382038
100420371500611686251000100010002645210201820372037157131895100010001000203720371110011000073116111786100020382038203820382038
100420371600611686251000100010002645210201820372037157131895100010001000203720371110011000073116111786100020382038203820382038
100420371500611686251000100010002645211201820372037157131895100010001000203720371110011000073116111786100020382038203820382038
100420851500611686251000100010002645211201820372037157131895100010001000203720371110011000073116111786100020382038203820382038
100420371500611686251000100010002645211201820372037157131895100010001000203720371110011000073116111786100020382038203820382038
100420371500611686251000100010002645211201820372037157131895100010001000203720371110011000073116111786100020382038203820382038
100420371500611686251000100010002645211201820372037157131895100010001000203720371110011000073116111786100020382038203820382038
100420371500611686251000100010002645210201820372037157131895100010001000203720371110011000073116111786100020382038203820382038
100420371500611686251000100010002645210201820372037157131895100010001000203720371110011000073116111786100020382038203820382038

Test 2: Latency 1->2

Code:

  clz v0.16b, 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)03071e1f3f4e51inst 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)9fa1a8acbranch mispredict (cb)cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204200371501006119686251012512510000125100005002847521020018200372003718421318745101002001000020010000200372003711102011009910010010000100000071011611197910100001002003820038200382003820038
102042003715000061196862510100100100001001000050028475210200182003720037184213187451010020010000200100002003720037111020110099100100100001000000710217221979125100001002003820038200382003820038
10204200371500006119686251010010010000100100006262847521020018200372003718421318745102542001000020010000200372003711102011009910010010000100000071011611197910100001002003820038200382003820038
102042003715000012019686251010010010000100100005002847521020018200372003718421318745101002001000020010000200372003711102011009910010010000100030071011611197910100001002003820038200382003820038
1020420037150000611968625101001001000010010000500284752102001820037200371842131874510125200100002001000020037200371110201100991001001000010002442071011611197910100001002003820038200382003820038
1020420037150000125619686251012512510000125100006262847521020018200372003718442318745101002001000020010000200372003711102011009910010010000100000071011611197910100001002003820038200382003820038
10204200371500006119686251010010010000100100005002847521020018200372003718429318745101002001000020010000200372003711102011009910010010000100010071011611197910100001002003820038200382003820038
1020420037150000749196862510100100100001001000050028475210200182003720037184213187451010020010000200100002003720037111020110099100100100001000230071021611197910100001002003820038200382003820038
10204200371500006119686251010012510000125100006262847521020018200372003718421318745101002001000020010000200372003711102011009910010010000100000071011611197910100001002003820038200382003820038
10204200371500006119686251010010010000100100005002847521020018200372003718421318744101252001000020010000200372003711102011009910010010000100000071011611197910100001002003820038200382003820038

1000 unrolls and 10 iterations

Result (median cycles for code): 2.0037

retire (01)cycle (02)0308191e1f3f4e51inst 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)9fa6a8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
100242003715000002981968625100101010000101000050284752112001820084201321844331876710010201000020100002003720037111002110910101000010010640316331978610000102003820038200382003820038
100242003715000001031968625100101010000101000050284752112001820037200371844331876710010201000020100002003720037111002110910101000010000640316331978610000102003820038200382003820038
10024200371500000821968625100101010000101000050284752112001820037200371844331876710010201000020100002003720037111002110910101000010000640316331978610000102003820038200382003820038
10024200371500000611968625100101010000101000050284752102001820037200371844331876710010201000020100002003720037111002110910101000010000640316331978610000102003820038200382003820038
10024200371500000611968625100101010000101000050284752112001820037200371844331876710010201000020100002003720037111002110910101000010000640316331978610000102003820038200382003820038
10024200371500300611968625100101010000101000050285131312001820037200371844331876710010201000020100002003720037111002110910101000010010640316331978610000102003820038200382003820038
10024200371500016203181968625100101010000101000050284752112001820037200371844331876710010201000020100002003720037111002110910101000010000640316331978610000102003820038200382003820038
100242003715000001031968625100101010000101000050284752112001820037200371844331876710010201000020100002003720037111002110910101000010000640316331978610000102003820038200382003820038
100242003715000001511968625100101010000101000050284752102001820037200371844331876710010201000020100002003720037111002110910101000010000640316331978610000102003820038200382003820038
1002420037150000027519686251001010100001010000502847521020018200372003718443111876710010201000020100002003720037111002110910101000010000640316331978610000102003820038200382003820038

Test 3: throughput

Count: 8

Code:

  clz v0.16b, v8.16b
  clz v1.16b, v8.16b
  clz v2.16b, v8.16b
  clz v3.16b, v8.16b
  clz v4.16b, v8.16b
  clz v5.16b, v8.16b
  clz v6.16b, v8.16b
  clz v7.16b, 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)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)60696d6edispatch stall (70)72scheduler 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)9fa1a8acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80204200601500050258010810080008100800205006401320200192003820038997776998980120200800322008003220038200381180201100991001008000010000011151180160020035800001002003920039200392003920039
80204200381500094258010810080008100800205006401321200192003820038997706998980120200800322008003220038200381180201100991001008000010002911151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401320200192003820038997706998980120200800322008003220038200381180201100991001008000010000011151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401320200192003820038997706998980120200800322008003220038200381180201100991001008000010000011151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401321200192003820038997706998980120200800322008003220038200381180201100991001008000010000011151180160020035800001002003920039200392003920039
802042003815003115258010810080008100800205006401320200192003820038997706998980120200800322008003220038200381180201100991001008000010000011151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401321200192003820038997706998980120200800322008003220038200381180201100991001008000010000011151180160020035800001002003920039200392003920039
802042003815002429258010810080008100800205006401321200192003820038997706998980120200800322008003220038200381180201100991001008000010000011151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401320200192003820038997706998980120200800322008003220038200381180201100991001008000010000011151180160020035800001002003920039200392003920039
80204200381500029258010810080008100800205006401320200192003820038997706998980120200800322008003220038200381180201100991001008000010000011151180160020035800001002003920039200392003920039

1000 unrolls and 10 iterations

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

retire (01)cycle (02)030b0e191e1f3f51inst 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)5f6061696d6edispatch 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)9fa8a9accfd0d2d5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8002420050150020008725800101080000108000050640000010200192003820038999631001880010208000020800002003820038118002110910108000010000502000316342003580000102003920039200392003920039
8002420038149000004525800101080000108000050640000010200192003820038999631001880010208000020800002003820038118002110910108000010000502000316442003580000102003920039200392003920039
8002420038150000003925800101080000108000050640000010200192003820038999631001880010208000020800002003820038118002110910108000010000502000516542003580000102003920039200392003920039
80024200381500009606225800101080000108000050640000010200192003820038999631001880010208000020800002003820038118002110910108000010000502000316442003580000102003920039200392003920039
8002420038150000003925800101080000108000050640000010200192003820038999631001880010208000020800002003820038118002110910108000010000502000316342003580000102003920039200392003920039
8002420038150000003925800101080000108000050640000010200192003820038999631001880010208000020800002003820038118002110910108000010003502000316442003580000102003920039200392003920039
8002420038150000003925800101080000108000050640000010200192003820038999631001880010208000020800002003820038118002110910108000010100502000516552003580000102003920039200392003920039
80024200381500000014625800101080000108000050640000010200192003820038999631001880010208000020800002003820038118002110910108000010000502000416442003580000102003920039200392003920039
8002420038150001003925800101080000108000050640000010200192003820038999631001880010208000020800002003820038118002110910108000010000502000416442003580000102003920039200392003920039
8002420038150000003925800101080000108000050640000000200192003820038999631001880010208000020800002003820038118002110910108000010000502000516452003580000102003920039200392003920039