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

MSR (SSBS)

Test 1: uops

Code:

  msr s3_3_c4_c2_6, x0

Initialization

  mrs x0, s3_3_c4_c2_6

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 4.000

Issues: 1.000

Integer unit issues: 1.001

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)
4004	27024	1001	1001	1001
4004	27024	1001	1001	1001
4004	27024	1001	1001	1001
4004	27024	1001	1001	1001
4004	27024	1001	1001	1001
4004	27024	1001	1001	1001
4004	27024	1001	1001	1001
4004	27024	1001	1001	1001
4004	27024	1001	1001	1001
4004	27024	1001	1001	1001

Test 2: throughput

Code:

  msr s3_3_c4_c2_6, x0

Initialization

  mrs x0, s3_3_c4_c2_6

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code): 27.0729

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)
40204	270744	10101	10101	100	300	100	200	200	10001	100
40205	270752	10101	10101	100	300	100	200	200	10001	100
40204	270729	10101	10101	100	300	100	200	200	10001	100
40204	270729	10101	10101	100	300	100	200	200	10001	100
40204	270729	10101	10101	100	300	100	200	200	10001	100
40204	270729	10101	10101	100	300	100	200	200	10001	100
40204	270729	10101	10101	100	300	100	200	200	10001	100
40205	270752	10101	10101	100	300	100	200	200	10001	100
40205	270752	10101	10101	100	300	100	200	200	10001	100
40204	270729	10101	10101	100	300	100	200	200	10001	100

1000 unrolls and 10 iterations

Result (median cycles for code): 27.0094

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)
40024	270099	10011	10011	10	30	10	20	20	10001	10
40024	270094	10011	10011	10	30	10	20	20	10001	10
40024	270094	10011	10011	10	30	10	20	20	10001	10
40024	270094	10011	10011	10	30	10	20	20	10001	10
40024	270094	10011	10011	10	30	10	20	20	10001	10
40024	270094	10011	10011	10	30	10	20	20	10001	10
40025	270122	10011	10011	10	30	10	20	20	10001	10
40025	270127	10011	10011	10	30	10	20	20	10001	10
40024	270094	10011	10011	10	30	10	20	20	10001	10
40024	270094	10011	10011	10	30	10	20	20	10001	10