Icestorm: LDRH (unsigned offset) measurements

Code:

  ldrh w0, [x6, #8]

Initialization

  mov x0, 1
  mov x1, 2
  mov x8, 0

(no loop instructions)

1000 unrolls and 1 iteration

Retires: 1.000

Issues: 1.000

Integer unit issues: 0.001

Load/store unit issues: 1.000

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)	schedule ldst uop (55)	dispatch ldst uop (58)	simd uops in schedulers (5a)	dispatch uop (78)	map ldst uop (7d)	map ldst uop inputs (80)	? int output thing (e9)	? ldst retires (ed)
1005	675	1027	1	1026	1000	8238	1000	1000	1000	1	1000
1004	554	1001	1	1000	1000	8112	1000	1000	1000	1	1000
1004	547	1001	1	1000	1000	8112	1000	1000	1000	1	1000
1004	547	1001	1	1000	1000	8112	1000	1000	1000	1	1000
1004	547	1001	1	1000	1000	8112	1000	1000	1000	1	1000
1004	547	1001	1	1000	1000	8112	1000	1000	1000	1	1000
1004	547	1001	1	1000	1000	8112	1000	1000	1000	1	1000
1004	547	1001	1	1000	1000	8112	1000	1000	1000	1	1000
1004	547	1001	1	1000	1000	8112	1000	1000	1000	1	1000
1004	547	1001	1	1000	1000	8112	1000	1000	1000	1	1000

Test 2: Latency 1->2 (with chain penalty)

Chain cycles: 3

Code:

  ldrh w0, [x6, #8]
  eor x8, x8, x0
  eor x8, x8, x0
  add x6, x6, x8

Initialization

  mov x0, 1
  mov x1, 2
  mov x8, 0

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code, minus 3 chain cycles): 4.0047

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

retire uop (01)	cycle (02)	schedule uop (52)	schedule int uop (53)	schedule ldst uop (55)	dispatch int uop (56)	dispatch ldst uop (58)	int uops in schedulers (59)	simd uops in schedulers (5a)	dispatch uop (78)	map int uop (7c)	map ldst uop (7d)	map int uop inputs (7f)	map ldst uop inputs (80)	? int output thing (e9)	? ldst retires (ed)	? int retires (ef)
40205	70149	40108	30107	10001	30130	10003	1859485	693973	40106	30212	10004	60224	10004	30003	10000	30100
40205	70092	40111	30109	10002	30135	10003	1859668	694073	40106	30212	10004	60224	10004	30003	10000	30100
40204	70047	40103	30103	10000	30103	10003	1859581	694063	40106	30212	10004	60224	10004	30003	10000	30100
40204	70047	40103	30103	10000	30103	10003	1859581	694063	40106	30212	10004	60224	10004	30003	10000	30100
40204	70047	40103	30103	10000	30103	10003	1859581	694063	40106	30212	10004	60224	10004	30003	10000	30100
40204	70047	40103	30103	10000	30103	10003	1859581	694063	40106	30212	10004	60224	10004	30003	10000	30100
40204	70047	40103	30103	10000	30103	10003	1859581	694063	40106	30212	10004	60224	10004	30003	10000	30100
40204	70047	40103	30103	10000	30103	10003	1859581	694063	40106	30212	10004	60224	10004	30003	10000	30100
40204	70047	40103	30103	10000	30103	10003	1859581	694063	40106	30212	10004	60224	10004	30003	10000	30100
40205	70077	40111	30109	10002	30135	10003	1859581	694063	40106	30212	10004	60224	10004	30003	10000	30100

1000 unrolls and 10 iterations

Result (median cycles for code, minus 3 chain cycles): 4.0047

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

retire uop (01)	cycle (02)	schedule uop (52)	schedule int uop (53)	schedule ldst uop (55)	dispatch int uop (56)	dispatch ldst uop (58)	int uops in schedulers (59)	simd uops in schedulers (5a)	dispatch uop (78)	map int uop (7c)	map ldst uop (7d)	map int uop inputs (7f)	map ldst uop inputs (80)	? int output thing (e9)	? ldst retires (ed)	? int retires (ef)
40025	70156	40018	30017	10001	30040	10003	1859725	694758	40016	30032	10004	60020	10000	30003	10000	30010
40024	70049	40013	30013	10000	30010	10000	1859706	694734	40010	30020	10000	60020	10000	30003	10000	30010
40025	70079	40021	30019	10002	30045	10000	1862433	695845	40010	30020	10000	60020	10000	30003	10000	30010
40024	70061	40013	30013	10000	30010	10000	1859706	694734	40010	30020	10000	60020	10000	30003	10000	30010
40024	70049	40013	30013	10000	30010	10000	1859706	694734	40010	30020	10000	60020	10000	30003	10000	30010
40024	70049	40013	30013	10000	30010	10000	1859706	694734	40010	30020	10000	60020	10000	30003	10000	30010
40024	70049	40013	30013	10000	30010	10000	1859706	694734	40010	30020	10000	60020	10000	30003	10000	30010
40024	70049	40013	30013	10000	30010	10000	1859706	694734	40010	30020	10000	60020	10000	30003	10000	30010
40024	70049	40013	30013	10000	30010	10000	1859706	694734	40010	30020	10000	60020	10000	30003	10000	30010
40024	70049	40013	30013	10000	30010	10000	1859706	694734	40010	30020	10000	60020	10000	30003	10000	30010

Test 3: throughput

Count: 8

Code:

  ldrh w0, [x6, #8]
  ldrh w0, [x6, #8]
  ldrh w0, [x6, #8]
  ldrh w0, [x6, #8]
  ldrh w0, [x6, #8]
  ldrh w0, [x6, #8]
  ldrh w0, [x6, #8]
  ldrh w0, [x6, #8]

Initialization

  mov x7, x6
  mov x8, x6
  mov x9, x6
  mov x10, x6
  mov x11, x6
  mov x12, x6
  mov x13, x6

(fused SUBS/B.cc loop)

100 unrolls and 100 iterations

Result (median cycles for code divided by count): 0.5006

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

retire uop (01)	cycle (02)	schedule uop (52)	schedule int uop (53)	schedule ldst uop (55)	dispatch int uop (56)	dispatch ldst uop (58)	int uops in schedulers (59)	simd uops in schedulers (5a)	dispatch uop (78)	map int uop (7c)	map ldst uop (7d)	map int uop inputs (7f)	map ldst uop inputs (80)	? int output thing (e9)	? ldst retires (ed)	? int retires (ef)
80205	40173	80129	101	80028	100	80008	300	480262	80108	200	80012	200	80012	1	80000	100
80204	40049	80101	101	80000	100	80008	300	640142	80108	200	80012	200	80012	1	80000	100
80204	40049	80101	101	80000	100	80008	300	640142	80108	200	80012	200	80012	1	80000	100
80204	40049	80101	101	80000	100	80008	300	640268	80108	200	80012	200	80012	1	80000	100
80204	40062	80101	101	80000	100	80008	300	640142	80108	200	80012	200	80012	1	80000	100
80204	40049	80101	101	80000	100	80008	300	640142	80108	200	80012	200	80012	1	80000	100
80204	40049	80101	101	80000	100	80008	300	640142	80108	200	80012	200	80012	1	80000	100
80204	40049	80101	101	80000	100	80059	300	346065	80159	200	80072	200	80012	1	80000	100
80204	40057	80101	101	80000	100	80008	300	640232	80108	200	80012	200	80012	1	80000	100
80204	40049	80101	101	80000	100	80008	300	640142	80108	200	80012	200	80012	1	80000	100

1000 unrolls and 10 iterations

Result (median cycles for code divided by count): 0.5007

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

retire uop (01)	cycle (02)	schedule uop (52)	schedule int uop (53)	schedule ldst uop (55)	dispatch int uop (56)	dispatch ldst uop (58)	int uops in schedulers (59)	simd uops in schedulers (5a)	dispatch uop (78)	map int uop (7c)	map ldst uop (7d)	map int uop inputs (7f)	map ldst uop inputs (80)	? int output thing (e9)	? ldst retires (ed)	? int retires (ef)
80025	40298	80041	11	80030	10	80008	30	320136	80018	20	80012	20	80000	1	80000	10
80024	40047	80011	11	80000	10	80000	30	640112	80010	20	80000	20	80000	1	80000	10
80024	40047	80011	11	80000	10	80000	30	640112	80010	20	80000	20	80000	1	80000	10
80024	40047	80011	11	80000	10	80000	30	640112	80010	20	80000	20	80000	1	80000	10
80024	40047	80011	11	80000	10	80000	30	640112	80010	20	80000	20	80000	1	80000	10
80024	40047	80011	11	80000	10	80000	30	640112	80010	20	80000	20	80000	1	80000	10
80024	40047	80011	11	80000	10	80000	30	640112	80010	20	80000	20	80069	1	80000	10
80024	40047	80011	11	80000	10	80000	30	640112	80010	20	80000	20	80000	1	80000	10
80024	40047	80011	11	80000	10	80000	30	640112	80010	20	80000	20	80000	1	80000	10
80024	40047	80011	11	80000	10	80000	30	640112	80010	20	80000	20	80000	1	80000	10

LDRH (unsigned offset)

Test 1: uops

1000 unrolls and 1 iteration

Test 2: Latency 1->2 (with chain penalty)

100 unrolls and 100 iterations

1000 unrolls and 10 iterations

Test 3: throughput

100 unrolls and 100 iterations

1000 unrolls and 10 iterations