Apple M1 Microarchitecture Research by Dougall Johnson

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

XTN (8H)

Test 1: uops

Code:

  xtn v0.8b, v0.8h
  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)03090b1e1f3f4e51inst 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)a0a1a6a8a9accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)f5f6f7f8fd
100420371500006116862510001000100026452120182037203715713189510001000100020372037111001100000000073216111786100020382038203820382038
100420371500006116862510001000100026452120182037203715713189510001000100020372037111001100000000073116111786100020382038203820382038
100420371500006116862510001000100026452120182037203715713189510001000100020372037111001100000000073116111786100020382038203820382038
1004203715000014516862510001000100026452120182037203715713189510001000100020372037111001100000000073116111786100020382038203820382038
100420371500006116752510001000115226452120542084208415758189911521169117020842037211001100000202198573116111786100020382074203820382038
100420371500006116862510001000100026452120182037203715713189510001000100020372037111001100000000073116111786100020382038203820382038
1004203715000034516862510001000100026452120182037203715717189510001000100020372037111001100000010073116111786100020382038203820382038
1004203715000012816862510001000100026452120182037208415713189510001000100020372037111001100000000073116111786100020382038203820382038
1004203715000010316862510001000100026452120182037203715713189510001000100020372037111001100010000073116111786100020382038203820382038
100420371600006116862510121000100026452120182037203715713189510001000100020372037111001100000000073116111786100020382038203820382038

Test 2: Latency 1->2

Code:

  xtn v0.8b, v0.8h
  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)0308090b18191e1f3a3f4e51inst 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)ea? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
10204200371560000000061196862510100100100001001000050028475211200182003720037184213187451010020010000200100002003720037111020110099100100100001000000000710116101979100100001002003820038200382003820038
10204200371610000000061196862510100100100001001000050028475211200182003720037184217187451027020010000200100002003720037111020110099100100100001000000000710116111979100100001002003820038200382003820038
10204200371550000000061196862510100100100001001000050028475211200182003720037184213187451010020010000200100002003720037111020110099100100100001000000000710116111979100100001002003820038200382003820038
10204200371550000000061196862510100100100001001000050028475211200182003720037184213187451010020010000200101662003720085111020110099100100100001000000000710116111979101100001002003820038200382003820038
10204200371550000000061196862510100100100001001000050028475211200182003720037184213187451010020010000200100002003720037111020110099100100100001000000000710116111979100100001002003820038200382003820038
10204200371560000000061196862510100100100001001000050028475211200182003720037184213187451010020010000200100002003720037111020110099100100100001000000000710116111979100100001002003820038200382003820038
10204200371550000000061196862510100100100001001000050028475211200182003720037184213187451010020010000200100002003720037111020110099100100100001000000000710116111979100100001002003820038200382003820038
10204200371550000000061196862510100100100001001000050028475211200182003720037184213187451010020010000200100002003720037111020110099100100100001000000000710116111979100100001002003820038200382003820038
10204200371550000000061196862510100100100001001000050028475211200182003720037184213187451010020010000200100002003720037111020110099100100100001000000000710116111979100100001002003820038200382003820038
102042003715500000088061196862510100100100001001000050028475211200182003720037184213187451010020010000200100002003720037111020110099100100100001000000000710116111979100100001002003820038200382003820038

1000 unrolls and 10 iterations

Result (median cycles for code): 2.0037

retire (01)cycle (02)0318191e3a3f4e51inst 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)9fa0a6a7a8a9accfd5d6ddinst fetch restart (de)e0? int output thing (e9)? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
1002420037155000061196862510010101000010100005028475210200182003720037184430318786100102010000201000020037200371110021109101010000100000006402162219786010000102003820038200382003820038
1002420037156000061196862510010101000010100005028475210200182003720037184430318767100102010000201000020037200371110021109101010000100000006402162219786010000102003820038200382003820038
10024200371560012061196862510010101000010100005028475211200182003720037184430318767100102010000201000020037200371110021109101010000100000006402162219786010000102003820038200382003820038
1002420037155000061196862510010101000010100005028475210200182003720037184430318767100102010000201000020037200371110021109101010000100000006402162219786010000102003820038200382003820038
1002420037155000061196862510010101000010100005028475210200182003720037184430318767100102010000201000020037200371110021109101010000100000006402162219786010000102003820038200382003820038
100242003715500002678196862510010101000010100005028475210200182003720037184430318767100102010000201000020037200371110021109101010000100000006402162219786010000102003820038200382003820038
10024200371550000261196862510010101000010100005028475210200182003720037184430318767100102010000201000020037200371110021109101010000100000006402162219786010000102003820038200382003820038
1002420037155000061196862510010101000010100005028475210200182003720037184430318767100102010000201000020037200371110021109101010000100000036402162219786010000102003820038201812008620228
10024201791550000441196862510010101000010100005028475210200182003720037184430318767100102010000201000020037200371110021109101010000100000006402162219786010000102003820038200382003820038
1002420037155000061196862510010101000010100005028475210200182003720037184430318767100102010000201000020037200371110021109101010000100000006402162219786010000102003820038200382003820038

Test 3: throughput

Count: 8

Code:

  xtn v0.8b, v8.8h
  xtn v1.8b, v8.8h
  xtn v2.8b, v8.8h
  xtn v3.8b, v8.8h
  xtn v4.8b, v8.8h
  xtn v5.8b, v8.8h
  xtn v6.8b, v8.8h
  xtn v7.8b, v8.8h
  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)03070918191e3f51inst 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)9fa0a1a6a8a9acc5branch mispredict (cb)cdcfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
8020420067155000007125801081008000810080020500640132020019200382003899776998980120200800322008003220038200381180201100991001008000010000010011151181162120035800001002003920039200392003920039
8020420038155000002925801081008000810080020500640132020019200382003899776998980120200800322008003220038200381180201100991001008000010000000011151182162220035800001002003920039200392003920039
8020420038155000002925801081008000810080020500640132020019200382003899776998980120200800322008003220038200381180201100991001008000010000000011151182162120035800001002003920039200392003920039
8020420038156000002925801081008000810080020500640132120019200382003899776998980120200800322008003220038200381180201100991001008000010000000311151182162220035800001002003920039200392003920039
8020420038156000002925801081008000810080020500640132020019200382003899776998980120200800322008003220038200381180201100991001008000010000000011151182162220035800001002003920039200392003920039
8020420038155000002925801081008000810080020500640132020019200382003899776998980120200800322008003220038200381180201100991001008000010000000011151182162220035800001002003920039200392003920039
80204200381610000017325801081008000810080020500640132120019200382003899776998980120200800322008003220191201954180201100991001008000010000000011151182162220082800001002003920039200392003920093
80204200881550002029258048810080008100800205006401320200192003820038100126998980120200800322008003220038200381180201100991001008000010000010011151182162120035800001002003920039200392003920039
8020420038155000002925801081008000810080020500640132020019200382003899776998980120200800322008003220038200381180201100991001008000010000010011151182161220035800001002003920039200392003920039
8020420038156000007125801081008000810080020500640132020019200382003899776998980120200800322008003220038200381180201100991001008000010000000011151182162220035800001002003920039200392003920039

1000 unrolls and 10 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)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)9fa8accfd5d6ddinst fetch restart (de)e0? fp/simd (ee)gpr retires (ef)f5f6f7f8fd
800242005015600000003925800101080000108000050640000020019200382003899960310018800102080000208000020038200381180021109101080000100050201216672003580000102003920039200392003920039
80024200381560000000392580010108000010800005064000002001920038200389996031001880010208000020800002003820038118002110910108000010005020416652003580000102003920039200392003920039
80024200381550000000392580010108000010800005064000002001920038200389996031001880010208000020800002003820038118002110910108000010005020516562003580000102003920039200392003920039
800242003815600000003925800101080000108000050640000020019200382003899960310018801072080097208009820087200381180021109101080000100050206161162003580000102009820088200392009920047
800242003815510011174116120258019710800001080000506400001200192003820038999603100188001020800002080000200382003811800211091010800001003502051611102003580000102003920039200392003920039
80024200381550000000392580010108000010800005064000012001920038200389996031001880010208000020800002003820038118002110910108000010005020516662003580000102003920039200392003920039
80024200381550000000392580010108000010800005064000012001920038200389996031001880010208000020800002003820038118002110910108000010005020516352003580000102003920039200392003920039
80024200381550000000622580010108000010800005064076002001920038200389996031001880010208000020800002003820038118002110910108000010005020416662003580000102003920039200392003920039
800242003815500000003925800101080000108000050640000120019200382003899960310018800102080000208000020038200381180021109101080000100050204161152003580000102003920039200392003920039
800242003815500000003925800101080000108000050640000120019200382003899960310018800102080000208000020038200381180021109101080000100050201116952003580000102003920039200392003920039