Apple Microarchitecture Research by Dougall Johnson

M1/A14 P-core (Firestorm): Overview | Base Instructions | SIMD and FP Instructions
M1/A14 E-core (Icestorm):  Overview | Base Instructions | SIMD and FP Instructions

FCVTNU (scalar, H to W)

Test 1: uops

Code:

  fcvtnu w0, h0
  mov x0, 1
  mov x1, 2

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 2.000

Issues: 3.000

Integer unit issues: 1.000

Load/store unit issues: 0.000

SIMD/FP unit issues: 2.000

retire uop (01)cycle (02)031e1f3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch simd uop (57)ldst uops in schedulers (5b)696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map simd uop (7e)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst int alu (97)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
2004541400432530001000200020001800052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541400432530001000200020001800052254154124832742000200020005415411110011000037321622538100010001000542542542542542
2004541400432530001000200020001800052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541400432530001000200020001800052254154124832742000200020005415411110011000007321622538100010001000542542542542542
20045415120432530001000200020001800052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541400432530001000200020001800052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541400432530001000200020001800052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541400432530001000200020001800052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541400432530001000200020001800052254154124832742000200020005415411110011000007321622538100010001000542542542542542
2004541400482530001000200020001800052254154124832742000200020005415411110011000007321622538100010001000542542542542542

Test 2: Latency 1->2 roundtrip

Code:

  fcvtnu w0, h0
  fmov d0, x0
  mov x0, 1
  mov x1, 2

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)03l2 tlb miss data (0b)18191e1f3f4f51schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)ldst uops in schedulers (5b)6061696b6d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map ldst uop (7d)map simd uop (7e)map int uop inputs (7f)map ldst uop inputs (80)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)ld unit uop (a6)st unit uop (a7)l1d cache writeback (a8)a9acc2cdcfd0d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
302041300389740000013002311941725401001010020000100001002000010000500621497914801034131300130130038130038125476312624630100200100002000020010000201301300381300381120201100991001010010000100010000000000131033162212952510000100001000010100130040130387130039130039130039
302041300389740000013002311941725401001010020000100001002000010000500621497914801034011300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000131022162212952510000100001000010100130039130039130039130039130039
3020413003897400012013002311941725401001011020000100001002000010000500621497914801034101300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000131012162212952510000100001000010100130039130039130039130039130039
302041300389740000013002311941725401001010020000100001002000010000500621497914801034101300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000131012162212952510000100001000010100130039130039130039130039130039
302041300389740000013002811941725401001010020000100001002000010000500621497914801034101300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000131012162212952510000100001000010100130039130039130039130039130039
302041300409740000013002311941725401001010020000100001002000010000500621497914801034001300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000131012162212952510000100001000010100130039130039130039130039130039
302041300419750000013002311941725401001010020000100001002000010000500621497914801034101300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000131012163212952510000100001000010100130039130039130039130045130039
302041300389740000013002311941525401001010020000100001002000010000500621497914801034101300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000131012162212952510000100001000010100130039130039130039130039130039
302041300389740000013002311941725401001010020000100001002000010000500621497914801034101300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000131013162312952510000100001000010100130039130039130039130039130039
302041300389740000013002311941725401001010020000100001002000010000500621497914801034101300130130038130038125476312624630100200100002000020010000200001300381300381120201100991001010010000100010000000000131012162212952510000100001000010100130039130039130039130039130039

1000 unrolls and 10 iterations

Result (median cycles for code): 13.0038

retire uop (01)cycle (02)03l2 tlb miss data (0b)18191e3f4f51schedule uop (52)schedule int uop (53)schedule simd uop (54)schedule ldst uop (55)dispatch int uop (56)dispatch simd uop (57)dispatch ldst uop (58)int uops in schedulers (59)simd uops in schedulers (5a)ldst uops in schedulers (5b)60696b6d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map ldst uop (7d)map simd uop (7e)map int uop inputs (7f)map ldst uop inputs (80)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)inst simd alu (9a)9fl1d tlb access (a0)l1d tlb miss (a1)ld unit uop (a6)l1d cache writeback (a8)a9acb6branch mispred nonspec (cb)cdcfd2d5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? ldst retires (ed)? simd retires (ee)? int retires (ef)f5f6f7f8fd
300241300389740000130023119417254001010010200001000010200001000050621517114800025113001301300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000127001161112952510000100001000010010130039130039130039130039130039
300241300389740000130023119417254001010010200001000010200001000050621795514800361113001301300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000127001161112952510000100001000010010130039130039130039130039130039
300241300389740000130023119417254001010010200001000010200001000050621910714800592113001301300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000300000127001161112952510000100001000010010130039130039130039130039130040
300241300389740000130023119417254001010010200001000010200001000050621670714800025113001301300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000127001161112952510000100001000010010130039130039130039130039130039
300241300389740009130023119417254001010010200001000010200001000050621641914800025113001301300381300681254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000127001161112958010000100001000010010130039130039130039130039130039
300241300389740000130023119417254001010010200001000010201261000050621526714800025113001301300381300381254983126268300102010000200002010000200001300381300421120021109101001010000100010000000000127001161112952510000100001000010010130039130039130039130039130039
300241300389740000130023119417254001010010200001000010200001000050621862714800249113001301300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000127001161112952510000100001000010010130039130039130039130039130039
300241300389740000130023119417254001010010200001000010200001000050621733114800025113001301300381300381254983126268300102010000200002010000200001300381300381120022109101001010000100010000006000127001161112952510000100001000010010130039130039130039130039130039
300241300389740000130023119417254001010010200001000010200001000050621790714800248113001301300381300381254983126268300102010000200002010000200001300381300382120021109101001010000100010000000000127001161112952510000100001000010010130039130039130039130039130039
300241300389740000130023119417254001010010200001000010200001000050621992314800025113001301300381300381254983126268300102010000200002010000200001300381300381120021109101001010000100010000000000127001161112952510000100001000010010130039130039130039130039130039

Test 3: throughput

Count: 8

Code:

  fcvtnu w0, h8
  fcvtnu w1, h8
  fcvtnu w2, h8
  fcvtnu w3, h8
  fcvtnu w4, h8
  fcvtnu w5, h8
  fcvtnu w6, h8
  fcvtnu w7, h8
  mov x8, 9

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.5005

retire uop (01)cycle (02)03l2 tlb miss instruction (0a)l2 tlb miss data (0b)18191e1f3a3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)9fl1d tlb access (a0)l1d tlb miss (a1)ld unit uop (a6)l1d cache writeback (a8)a9acc2branch cond mispred nonspec (c5)branch mispred nonspec (cb)cdcfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1602044004131100000003225240104801001600041001600205001440132040022400414004119977619992160120200160032200160032400414004111802011009910080100100000001380111511711600400388000080000801004004240042400424004240042
160204400413110000000322524010480100160004100160020500144013204002240041400411997761999216012020016003220016003240041400411180201100991008010010000000810111511701600400388000080000801004004240042400424004240042
160204400413100000000322524010480100160004100160020500144013214002240041400411997761999216012020016003220016003240041400411180201100991008010010000052030111511701600400388000080000801004004240042400424004240042
160204400413110000000322524010480100160004100160020500144013214002240041400411997761999216012020016003220016003240041400411180201100991008010010000039000111511701600400388000080000801004004240042400424004240042
16020440041310000000032252401048010016000410016002050014401320400224004140041199776199921601202001600322001600324004140041118020110099100801001000009030111511701610400388000080000801004004240042400424004240042
160204400413100000000322524010480100160004100160020500144013214002240041400411997761999216012020016003220016003240041400411180201100991008010010000039000111511701600400388000080000801004004240042400424004240042
160204400413100000000322524010480100160004100160020500144013214002240041400411997761999216012020016003220016003240041400411180201100991008010010000079030111511701600400388000080000801004004240042400424004240042
160204400413100000000322524010480100160004100160020500144013214002240041400411997761999216012020016003220016003240041400411180201100991008010010000067090111511701600400388000080000801004004240042400424004240042
160204400413100000000882524010480100160004100160020500144184504002240041400411997761999216012020016003220016003240041400411180201100991008010010000045030111511701600400388000080000801004004240042400424004240042
16020440041310000000032252401048010016000410016002050014401321400224004140041199776199921601202001600322001600324004140041118020110099100801001000000030111511701600400388000080000801004004240042400424004240042

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.5005

retire uop (01)cycle (02)031e3f51schedule uop (52)schedule int uop (53)schedule simd uop (54)dispatch int uop (56)dispatch simd uop (57)int uops in schedulers (59)ldst uops in schedulers (5b)60696d6emap stall dispatch (70)map rewind (75)map stall (76)dispatch uop (78)map int uop (7c)map simd uop (7e)map int uop inputs (7f)map simd uop inputs (81)8283flush restart other nonspec (84)85inst all (8c)inst branch (8d)inst branch taken (90)inst branch cond (94)inst int alu (97)9fl1d tlb access (a0)l1d tlb miss (a1)l1d cache writeback (a8)accfd5map dispatch bubble (d6)ddfetch restart (de)e0? int output thing (e9)? simd retires (ee)? int retires (ef)f5f6f7f8fd
1600244005530069422524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000502031653400388000080000800104004240042400424004240042
160024400413000422524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000502021655400388000080000800104004240042400424004240042
160024400413000422524001080010160000101600005014400001400224004140041200213200211600102016000020160000400414004111800211091080010100200502051665400388000080000800104004240042400424004240042
1600244004129939422524001080010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100080502061656400388000080000800104004240042400424004240042
160024400413000422524001080010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100000502051632400388000080000800104004240042400424004240042
160024400413000422524001080010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100000502061656400388000080000800104004240042400424004240042
1600244004130048422524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000502021653400388000080000800104004240042400424004240042
160024400413000422524001080010160000101600005014400000400224004140041200923200211600102016000020160000400414004111800211091080010100000502031623400388000080000800104004240042400424004240042
16002440041301452532524001080010160000101600005014400000400224004140041199963200211600102016000020160000400414004111800211091080010100000502021623400388000080000800104004240042400424004240042
160024400413000422524001080010160000101600005014400001400224004140041199963200211600102016000020160000400414004111800211091080010100000502021655400388000080000800104004240042400424004240042