Apple M1 Microarchitecture Research by Dougall Johnson

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

SHRN (8H)

Test 1: uops

Code:

  shrn v0.8b, v0.8h, #3
  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)031e3f4e51inst issue (52)~issue fp/simd (54)~dispatch fp/simd (57)huge thing fp/simd (5b)696d6edispatch 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)accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
1004303723061254725100010001000398160301830373037241432895100010001000303730371110011000073316332629100030383038303830383038
10043037221261254725100010001000398160301830373037241432895100010001000303730371110011000373316332629100030383038303830383038
10043037230156254725100010001000398160301830373037241432895100010001000303730371110011000073316332629100030383038303830383038
1004303722061254725100010001000398160301830373037241432895100010001000303730371110011000073316332629100030383038303830383038
1004307322061254725100010001000398160301830373037241432895100010001000303730371110011000073316332629100030383038303830383038
1004303722201346254725100010001000398160301830373084241432895100010001000303730371110011000073316332629100030383038303830383038
1004303722061254725100010001000398160301830373037241432895100010001000303730371110011000073316332629100030383038303830383038
1004303723061254725100010001000398160301830373037241432895100010001000303730371110011000073316332629100030383038303830383038
1004303722061254725100010001000398160301830373037241432895100010001000303730371110011000088316332629100030383038303830383038
1004303723061254725100010001000398160301830373037241432895100010001000303730371110011000073316332629100030383038303830383038

Test 2: Latency 1->2

Code:

  shrn v0.8b, v0.8h, #3
  movi v0.16b, 1
  movi v1.16b, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)031e1f3f4e51inst 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)60696b6d6edispatch 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)9fa0a6a8a9acc2c5cfd0d5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1020430037225001262954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710011611296330100001003003830038300383003830038
1020430037225001912954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710011611296330100001003003830038300383003830038
1020430037225001892954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710011611296330100001003003830038300383003830038
1020430037225001892954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710011611296330100001003003830038300383003830038
1020430037224001262954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710011611296330100001003003830038300863008630038
1020430037225008292954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710011611296330100001003003830038300383003830038
1020430037224001262954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710011611296330100001003003830038300383003830038
102043003722500822954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000000710011611296330100001003003830038300383003830038
1020430037225001032954725101001001000010010000500427716003001803003730037282643287451010020210000200100003003730037111020110099100100100001000000000710011611296330100001003003830038300383003830038
1020430037225001032954725101001001000010010000500427716003001803003730037282643287451010020010000200100003003730037111020110099100100100001000000300710011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)030b18191e1f3a3f4e51inst 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)9fa0a1a6a8a9acc2cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1002430037225000900210295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000006405165629629110000103003830038300383003830038
1002430037225000000822954725100181010000101000050427716003001830133301782829920288171046322104842210659301323017841100211091010100001000000006406166729629010000103003830038300383003830038
100243003722500000061295472510010101000010100005042771600300183003730037282863287861001020100002010000300373003711100211091010100001000000606406166629629010000103003830038300383003830038
1002430037225000000124295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000006407166729629010000103003830038300383003830038
100243003722500013588061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000006406166629629010000103003830038300383003830038
100243003722500000061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000006407167629629010000103003830038300383003830038
1002430037224000000107295472510010101000010100005042771601300183003730037282863287671001020100002010000300373003711100211091010100001000000006406167629629010000103003830038300383003830038
1002430037225000000612954725100101010000101000050427716003001830037300372828632876710010201000020100003003730037111002110910101000010000520306406167629629010000103003830038300383003830038
1002430037225000000214295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000000906407166729629010000103003830038300383003830038
1002430037225000000823295472510010101000010100005042771601300183008430084282866287901001020100002010000300373003711100211091010100001000000006407167629629010000103003830038300383003830038

Test 3: throughput

Count: 8

Code:

  shrn v0.8b, v8.8h, #3
  shrn v1.8b, v8.8h, #3
  shrn v2.8b, v8.8h, #3
  shrn v3.8b, v8.8h, #3
  shrn v4.8b, v8.8h, #3
  shrn v5.8b, v8.8h, #3
  shrn v6.8b, v8.8h, #3
  shrn v7.8b, v8.8h, #3
  movi v8.16b, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.2506

retire (01)cycle (02)0307080b0e1e3f51inst 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)6061696d6edispatch 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)9fa7a8a9acc5branch mispredict (cb)cdcfd0d2d5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
80204200591500000030258010810080008100800205006401321020020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118000160020036800001002004020040200402004020040
80204200391500000030258020810080008100800205006401320020020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118000160020036800001002004020040200402004020040
80204200391500000030258010810080008100800205006401321020020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118000160020036800001002004020040200402004020040
80204200391500000074258010810080008100800205006401321020020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118000160020036800001002004020040200402004020040
80204200391500000030258010810080008100800205006401320020020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118000160020036800001002004020040200402004020040
80204200391500000030258010810080008100800205006401320020020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118000160020036800001002004020040200402004020040
80204200391502010030258010810080212100800205006401321020020200392003999776999080120200800322008003220039200391180201100991001008000010000001115118000160020036800001002004020040200402004020040
80204200391500000030258010810080008100800205006401321020020200392003999776999080120200800322008003220039200391180201100991001008000010001001115118000160020036800001002004020040200402004020040
80204200391500000030258010810080008100800205006401321020020200392003999769998680128200800382008003820048200491180201100991001008000010000002225128001231120045800001002004920049200492004920050
802042004915000000106268011610080016100800285006401960020029200482004999766999080120200800322008003220039200391180201100991001008000010000001115118000160020036800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)03181e3f51inst 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)5f60696d6edispatch 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)9fa6a8acbranch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242005115000402580010108000010800005064000001200202003920039999631001980010208000020800002003920039118002110910108000010000005020216112003680000102004020040200402004020040
800242003915000402580010108000010800005064000001200202003920039999631001980010208000020800002003920039118002110910108000010000005020116112003680000102004020040200402004020040
800242003915000402580010108000010800005064000001200202003920039999631001980010208000020800002003920039118002110910108000010200005020116112003680000102004020040200402004020040
800242003915000402580010108000010800005064000010200202003920039999631001980010208000020800002003920039118002110910108000010000005020116112003680000102004020040200402004020040
800242003915000402580010108000010800005064000000200202003920039999631001980010208000020800002003920039118002110910108000010000005020116112003680000102004020040200402004020040
800242003915000402580010108000010800005064000000200202003920039999631001980010208000020800002003920039118002110910108000010030005020116112003680000102004020040200402004020040
800242003915000402580010108000010800005064000001200202003920039999631001980010208000020800002003920039118002110910108000010000005020216222003680000102004020040200402004020040
800242003915000402580010108000010800005064000001200202003920039999631001980010208000020800002003920039118002110910108000010000005020216112003680000102004020040200402004020040
800242003915000402580010108000010800005064000001200202003920039999631001980010208000020800002003920039118002110910108000010000015020216222003680000102004020040200402004020040
800242003915000405080010108000010800005064000000200202003920039999631001980010208000020800002003920039118002110910108000010000005020116112003680000102004020040200402004020040