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

YIELD

Test 1: uops

Code:

  yield

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 0.000

Integer unit issues: 0.001

Load/store unit issues: 0.000

SIMD/FP unit issues: 0.000

Recorded non-zero counters (first 10 of 64 runs)

retire uop (01)	cycle (02)	schedule uop (52)	schedule int uop (53)	? int output thing (e9)
1004	547	1	1	1
1004	282	1	1	1
1004	275	1	1	1
1004	275	1	1	1
1004	275	1	1	1
1004	275	1	1	1
1004	275	1	1	1
1004	275	1	1	1
1004	275	1	1	1
1004	275	1	1	1

Test 2: throughput

Code:

  yield

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 0.2585

Recorded non-zero counters (first 10 of 64 runs)

retire uop (01)	cycle (02)	schedule uop (52)	schedule int uop (53)	dispatch int uop (56)	int uops in schedulers (59)	dispatch uop (78)	map int uop (7c)	map int uop inputs (7f)	? int output thing (e9)	? int retires (ef)
10204	2621	101	101	100	300	100	200	200	1	100
10204	2585	101	101	100	300	100	200	200	1	100
10204	2585	101	101	100	300	100	200	200	1	100
10204	2585	101	101	100	300	100	200	200	1	100
10204	2585	101	101	100	300	100	200	200	1	100
10204	2585	101	101	100	300	100	200	200	1	100
10204	2585	101	101	100	300	100	200	200	1	100
10204	2585	101	101	100	300	100	200	200	1	100
10204	2585	101	101	100	300	100	200	200	1	100
10204	2585	101	101	100	300	100	200	200	1	100

1000 unrolls and 10 iterations

Result (median cycles for code): 0.2536

Recorded non-zero counters (first 10 of 64 runs)

retire uop (01)	cycle (02)	schedule uop (52)	schedule int uop (53)	dispatch int uop (56)	int uops in schedulers (59)	dispatch uop (78)	map int uop (7c)	map int uop inputs (7f)	? int output thing (e9)	? int retires (ef)
10024	2772	21	21	20	65	20	20	20	11	10
10024	2545	21	21	20	70	20	20	20	11	10
10024	2536	21	21	20	70	20	20	20	11	10
10024	2536	21	21	20	70	20	20	20	11	10
10024	2536	21	21	20	70	20	20	20	11	10
10024	2536	21	21	20	70	20	20	20	11	10
10024	2536	21	21	20	70	20	20	20	11	10
10024	2536	21	21	20	70	20	20	20	11	10
10024	2536	21	21	20	70	20	20	20	11	10
10024	2536	21	21	20	70	20	20	20	11	10