Apple M1 Microarchitecture Research by Dougall Johnson

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

SQSHRUN (S)

Test 1: uops

Code:

  sqshrun h0, s0, #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)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)a8a9accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073216222629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073216222629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100070073216222629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073216222629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073216222629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073216222629100030383038303830383038
1004303722061254725100010001000398160130183037303724143289510001000100030373037111001100000073216222629100030383038303830383038
10043037230612547251000100010003981601301830373037241432895100010001000303730371110011000001873216222629100030383038303830383038
1004303722061254725100010001000398160130183037303724143289510001000100030373037111001100000073216222629100030383038303830383038
1004303723061254725100010001000398160130183037303724143289510001000100030373037111001100000073216222629100030383038303830383038

Test 2: Latency 1->2

Code:

  sqshrun h0, s0, #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)03071e3a3f4e51inst 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)9fa1a8acc2c5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1020430037225000103295472510100100100001001000050042771600300183003730037282711028739101002001000820010008300373003711102011009910010010000100012783011171801600296450100001003003830038300383003830038
1020430037225012016629547251010010810024100100005004277160030018300373003728271628741101002001000820010008300373003711102011009910010010000100210211171701600296450100001003003830038300383003830038
10204300372250006129526251010012510000100100005344277160030054300853023028264328745102712001016820010166302793013611102011009910010010000100000000071011611296330100001003003830038300383003830038
10204300372250006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000000071011711296330100001003003830038300383003830038
10204300372240006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000000071011611296332100001003003830181300383003830038
10204300372250006129547991014010010040126106006544279864130018300373003728271328744101252001000020010000300373003711102011009910010010000100000000071211611296330100001003003830038300383003830038
102043003722509906129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000000071411611296330100001003003830038300383003830038
10204300372250006129547441010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000000071011611296330100001003003830038300383003830038
10204300372250006129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000000071011611296330100001003008030038300383003830038
102043003722503906129547251010010010000100100005004277160030018300373003728264328745101002001000020010000300373003711102011009910010010000100000000071011611296330100001003003830038300383003830038

1000 unrolls and 10 iterations

Result (median cycles for code): 3.0037

retire (01)cycle (02)03080b18191e1f3f4e51inst 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)9fa0a1a6a7a8a9acc2branch mispredict (cb)cfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
100243003722500000039982950280100451310024131075056428121603019830178301792830925288441061222106502210330301813022741100211091010100001020301011063007304242229629010000103003830038302733003830038
100243003722500011505233295022091009623100401211500814286624030342305103051228326472895511513201164422116253022430507121100211091010100001002200227990408763162329629010000103003830038300383003830038
10024300372250000006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000000006402162229629010000103003830038300383003830038
100243003722500000010529547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000000006402162229629010000103003830038300383003830038
10024300372240000006129547251001010100001010000504277160030018300373003728286328767100102010000201000030037300371110021109101010000100000000006682162229629010000103003830038300383003830038
10024300372250000006129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100000000006403162229629010000103003830038300383003830038
10024300372250000006129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100000000006402162229629010000103003830038300383003830038
100243003722500000061295472510010101000010100005042771600300183003730037282863287671001020100002010000300373003711100211091010100001000004400016402162229629010000103003830038300383003830038
10024300372250000006129547251001010100001010000504277160130018300373003728286328767100102010000201000030037300371110021109101010000100000000006402162229629010000103003830038300383003830038
10024300372250000006129547251001010100001010000504278512130270304173027528318392893410310261147324104853046130417101100211091010100001004301025405208082962229953310000103041830416304153041730416

Test 3: throughput

Count: 8

Code:

  sqshrun h0, s8, #3
  sqshrun h1, s8, #3
  sqshrun h2, s8, #3
  sqshrun h3, s8, #3
  sqshrun h4, s8, #3
  sqshrun h5, s8, #3
  sqshrun h6, s8, #3
  sqshrun h7, s8, #3
  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)0308090b18191e1f3f51inst 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)9fa0a1a8acc2c5branch mispredict (cb)cdcfd5d6inst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8020420049150000001206952580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151183160200360800001002004020040200402004020040
80204200391500000000302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160200360800001002004020040200402004020040
8020420039150000001206069980603102805061008054450064346412026620238202451001523100958053220080446202804472025220249518020110099100100800001000011895211151870670202361800001002030020294203042024320243
802042029915110044111926485011580599102805011018054751164421612022520141202951002428100938065020080539202805522029920286618020110099100100800001000000011151180161202430800001002029220301202502031120040
80204200391500000000952580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000411151180160200360800001002004020040200402004020040
80204200391500000000302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160200360800001002004020040200402004020040
80204200391500000000302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160200360800001002004020040200402004020040
80204200391500000090302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160200360800001002004020040200402004020040
802042003915000000330302580108100800081008002050064013202002020039200399977699908012020080032200800322003920039118020110099100100800001000000011151180160200360800001002004020040200402004020040
80204200391500000060302580108100800081008002050064013212002020039200399977699908012020080032200800322003920039118020110099100100800001000010011151180160200360800001002004020040200402004020040

1000 unrolls and 10 iterations

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

retire (01)cycle (02)031e3f51inst 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)9fa0a1accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8002420051150574051800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050201316952003680000102004020040200402004020040
80024200391500402580010108000010800005064000012002020039200399996310019800102080000208000020039200391180021109101080000100005020616992003680000102004020040200402004020040
80024200391502704025800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050205164142003680000102004020040200402004020040
800242003915008425800101080000108000050640000120020200392003999963100198001020800002080000200392003911800211091010800001000050205161392003680000102004020040200402004020040
800242003915004025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000050201116842003680000102004020040200402004020040
8002420039150184025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000050201216892003680000102004020040200402004020040
800242003915004025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000050208161182003680000102004020040200402004020040
8002420039150498402580010108000010800005064000002002020039200399996310019800102080000208000020039200391180021109101080000100005020916942003680000102004020040200402004020040
80024200391500402580010108000010800005064000012002020039200399996310019800102080000208000020039200391180021109101080000100005020916842003680000102004020040200402004020040
8002420039150274025800101080000108000050640000020020200392003999963100198001020800002080000200392003911800211091010800001000050209161042003680000102004020040200402004020040