OV - exec - Loop 239

	Loop Id: 239	Module: exec	Source: generate_chunk.cpp:77-80	Coverage: 0.03%

0x436048 LD1R	{V0.2D}, [X6]    [3]

0x43604c ADD	X22, X0, #16

0x436050 ADD	X21, X0, #32

0x436054 ADD	X12, X0, #48

0x436058 STR	Q0, [X11, X0]    [7]

0x43605c LD1R	{V1.2D}, [X5]    [2]

0x436060 STR	Q1, [X10, X0]    [6]

0x436064 LD1R	{V2.2D}, [X4]    [1]

0x436068 STR	Q2, [X9, X0]    [5]

0x43606c LD1R	{V3.2D}, [X3]    [8]

0x436070 STR	Q3, [X8, X0]    [4]

0x436074 ADD	X0, X0, #64

0x436078 LD1R	{V4.2D}, [X6]    [3]

0x43607c STR	Q4, [X11, X22]    [7]

0x436080 LD1R	{V5.2D}, [X5]    [2]

0x436084 STR	Q5, [X10, X22]    [6]

0x436088 LD1R	{V6.2D}, [X4]    [1]

0x43608c STR	Q6, [X9, X22]    [5]

0x436090 LD1R	{V7.2D}, [X3]    [8]

0x436094 STR	Q7, [X8, X22]    [4]

0x436098 LD1R	{V16.2D}, [X6]    [3]

0x43609c STR	Q16, [X11, X21]    [7]

0x4360a0 LD1R	{V17.2D}, [X5]    [2]

0x4360a4 STR	Q17, [X10, X21]    [6]

0x4360a8 LD1R	{V18.2D}, [X4]    [1]

0x4360ac STR	Q18, [X9, X21]    [5]

0x4360b0 LD1R	{V19.2D}, [X3]    [8]

0x4360b4 STR	Q19, [X8, X21]    [4]

0x4360b8 LD1R	{V28.2D}, [X6]    [3]

0x4360bc STR	Q28, [X11, X12]    [7]

0x4360c0 LD1R	{V29.2D}, [X5]    [2]

0x4360c4 STR	Q29, [X10, X12]    [6]

0x4360c8 LD1R	{V30.2D}, [X4]    [1]

0x4360cc STR	Q30, [X9, X12]    [5]

0x4360d0 LD1R	{V31.2D}, [X3]    [8]

0x4360d4 STR	Q31, [X8, X12]    [4]

0x4360d8 CMP	X14, X0

0x4360dc B.NE	436048

/home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/build/CloverLeaf2.0-CXX/src/omp/generate_chunk.cpp: 77 - 80

--------------------------------------------------------------------------------

77:       field.energy0(i, j) = state_energy[0];

78:       field.density0(i, j) = state_density[0];

79:       field.xvel0(i, j) = state_xvel[0];

80:       field.yvel0(i, j) = state_yvel[0];

Coverage (%)	Name	Source Location	Module
►100.00+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►50.00+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►50.00+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►75.53+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►24.47+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►87.50+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►12.50+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►93.59+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►6.41+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►95.63+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►4.37+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►96.78+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►3.22+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►97.64+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►2.36+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►97.99+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►2.01+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►98.27+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►1.73+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

Coverage (%)	Name	Source Location	Module
►98.48+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►1.52+	GOMP_parallel		libgomp.so.1.0.0
○	generate_chunk(int, global_var[...]	generate_chunk.cpp:84	exec
○	start(parallel_&, global_confi[...]	start.cpp:81	exec
○	initialise(parallel_&, std::ve[...]	clover_leaf.cpp:192	exec
○	main	clover_leaf.cpp:204	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.cpp:51	exec

min	med	avg	max

Percentile Index	10	20	30	40	50	60	70	80	90	100
Value

min	med	avg	max

Percentile Index	10	20	30	40	50	60	70	80	90	100
Value

Path /

Metric	Value
CQA speedup if no scalar integer	1.00
CQA speedup if FP arith vectorized	1.00
CQA speedup if fully vectorized	2.67
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.33
Bottlenecks	P10, P11, P12,
Function	generate_chunk(int, global_variables&) [clone ._omp_fn.0]
Source	generate_chunk.cpp:77-80
Source loop unroll info	not unrolled or unrolled with no peel/tail loop
Source loop unroll confidence level	max
Unroll/vectorization loop type	NA
Unroll factor	NA
CQA cycles	10.67
CQA cycles if no scalar integer	10.67
CQA cycles if FP arith vectorized	10.67
CQA cycles if fully vectorized	4.00
Front-end cycles	4.75
P0 cycles	0.50
P1 cycles	0.50
P2 cycles	1.25
P3 cycles	1.25
P4 cycles	1.25
P5 cycles	1.25
P6 cycles	8.00
P7 cycles	8.00
P8 cycles	8.00
P9 cycles	8.00
P10 cycles	10.67
P11 cycles	10.67
P12 cycles	10.67
P13 cycles	0.00
P14 cycles	0.00
DIV/SQRT cycles	0.00
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	38.00
Nb uops	38.00
Nb loads	NA
Nb stores	16.00
Nb stack references	0.00
FLOP/cycle	0.00
Nb FLOP add-sub	0.00
Nb FLOP mul	0.00
Nb FLOP fma	0.00
Nb FLOP div	0.00
Nb FLOP rcp	0.00
Nb FLOP sqrt	0.00
Nb FLOP rsqrt	0.00
Bytes/cycle	12.00
Bytes prefetched	0.00
Bytes loaded	128.00
Bytes stored	0.00
Stride 0	4.00
Stride 1	0.00
Stride n	4.00
Stride unknown	0.00
Stride indirect	0.00
Vectorization ratio all	50.00
Vectorization ratio load	0.00
Vectorization ratio store	100.00
Vectorization ratio mul	NA
Vectorization ratio add_sub	NA
Vectorization ratio fma	NA
Vectorization ratio div_sqrt	NA
Vectorization ratio other	NA
Vector-efficiency ratio all	37.50
Vector-efficiency ratio load	25.00
Vector-efficiency ratio store	50.00
Vector-efficiency ratio mul	NA
Vector-efficiency ratio add_sub	NA
Vector-efficiency ratio fma	NA
Vector-efficiency ratio div_sqrt	NA
Vector-efficiency ratio other	NA

Metric	Value
CQA speedup if no scalar integer	1.00
CQA speedup if FP arith vectorized	1.00
CQA speedup if fully vectorized	2.67
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.33
Bottlenecks	P10, P11, P12,
Function	generate_chunk(int, global_variables&) [clone ._omp_fn.0]
Source	generate_chunk.cpp:77-80
Source loop unroll info	not unrolled or unrolled with no peel/tail loop
Source loop unroll confidence level	max
Unroll/vectorization loop type	NA
Unroll factor	NA
CQA cycles	10.67
CQA cycles if no scalar integer	10.67
CQA cycles if FP arith vectorized	10.67
CQA cycles if fully vectorized	4.00
Front-end cycles	4.75
P0 cycles	0.50
P1 cycles	0.50
P2 cycles	1.25
P3 cycles	1.25
P4 cycles	1.25
P5 cycles	1.25
P6 cycles	8.00
P7 cycles	8.00
P8 cycles	8.00
P9 cycles	8.00
P10 cycles	10.67
P11 cycles	10.67
P12 cycles	10.67
P13 cycles	0.00
P14 cycles	0.00
DIV/SQRT cycles	0.00
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	38.00
Nb uops	38.00
Nb loads	NA
Nb stores	16.00
Nb stack references	0.00
FLOP/cycle	0.00
Nb FLOP add-sub	0.00
Nb FLOP mul	0.00
Nb FLOP fma	0.00
Nb FLOP div	0.00
Nb FLOP rcp	0.00
Nb FLOP sqrt	0.00
Nb FLOP rsqrt	0.00
Bytes/cycle	12.00
Bytes prefetched	0.00
Bytes loaded	128.00
Bytes stored	0.00
Stride 0	4.00
Stride 1	0.00
Stride n	4.00
Stride unknown	0.00
Stride indirect	0.00
Vectorization ratio all	50.00
Vectorization ratio load	0.00
Vectorization ratio store	100.00
Vectorization ratio mul	NA
Vectorization ratio add_sub	NA
Vectorization ratio fma	NA
Vectorization ratio div_sqrt	NA
Vectorization ratio other	NA
Vector-efficiency ratio all	37.50
Vector-efficiency ratio load	25.00
Vector-efficiency ratio store	50.00
Vector-efficiency ratio mul	NA
Vector-efficiency ratio add_sub	NA
Vector-efficiency ratio fma	NA
Vector-efficiency ratio div_sqrt	NA
Vector-efficiency ratio other	NA

Path /

Average path: Display a virtual path defined by average values of all real paths

Function	generate_chunk(int, global_variables&) [clone ._omp_fn.0]
Source file and lines	generate_chunk.cpp:77-80
Module	exec

The loop is defined in /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/build/CloverLeaf2.0-CXX/src/omp/generate_chunk.cpp:77-80.

The related source loop is not unrolled or unrolled with no peel/tail loop.

gain
potential
hint
expert

Vectorization

Your loop is partially vectorized. Only 37% of vector register length is used (average across all VPU instructions). By fully vectorizing your loop, you can lower the cost of an iteration from 10.67 to 4.00 cycles (2.67x speedup).

Details

50% of VPU instructions are used in vector version (process two or more data elements in vector registers):

0% of VPU loads are used in vector version.

Since your execution units are vector units, only a fully vectorized loop can use their full power.

Workaround

Try another compiler or update/tune your current one
Remove inter-iterations dependences from your loop and make it unit-stride:
- If your arrays have 2 or more dimensions, check whether elements are accessed contiguously and, otherwise, try to permute loops accordingly: C storage order is row-major: for(i) for(j) a[j][i] = b[j][i]; (slow, non stride 1) => for(i) for(j) a[i][j] = b[i][j]; (fast, stride 1)
- If your loop streams arrays of structures (AoS), try to use structures of arrays instead (SoA): for(i) a[i].x = b[i].x; (slow, non stride 1) => for(i) a.x[i] = b.x[i]; (fast, stride 1)

No data for this section

Slow data structures access

Detected data structures (typically arrays) that cannot be efficiently read/written

Details

Constant non-unit stride: 4 occurrence(s)

Non-unit stride (uncontiguous) accesses are not efficiently using data caches

Workaround

Try to reorganize arrays of structures to structures of arrays
Consider to permute loops (see vectorization gain report)

Matching between your loop (in the source code) and the binary loop

The binary loop does not contain any FP arithmetical operations. The binary loop is loading 128 bytes.

General properties

nb instructions	38
nb uops	38
loop length	152
used w registers	0
used x registers	13
used b registers	0
used h registers	0
used s registers	0
used d registers	0
used q registers	16
used v registers	16
used z registers	0
nb stack references	0

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	4.75 cycles
front end	4.75 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	1.25	1.25	1.25	1.25	8.00	8.00	8.00	8.00	10.67	10.67	10.67	0.00	0.00
cycles	0.50	0.50	1.25	1.25	1.25	1.25	8.00	8.00	8.00	8.00	10.67	10.67	10.67	0.00	0.00

Execution ports to units layout:

P0: BRU
P1: BRU
P2: ALU
P3: ALU
P4: ALU
P5: ALU
P6 (128 bits): VPU, FP store data, ALU, DIV/SQRT
P7 (128 bits): VPU, ALU, FP store data
P8 (128 bits): VPU, ALU, DIV/SQRT
P9 (128 bits): ALU, VPU
P10 (256 bits): store address, load
P11 (256 bits): store address, load
P12 (256 bits): load
P13 (64 bits): store data
P14 (64 bits): store data

Cycles executing div or sqrt instructions	NA
Longest recurrence chain latency (RecMII)	1.00

Cycles summary

Front-end	4.75
Dispatch	10.67
Data deps.	1.00
Overall L1	10.67

Vectorization ratios

all	50%
load	0%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	NA (no add-sub vectorizable/vectorized instructions)
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	NA (no other vectorizable/vectorized instructions)

Vector efficiency ratios

all	37%
load	25%
store	50%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	NA (no add-sub vectorizable/vectorized instructions)
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	NA (no other vectorizable/vectorized instructions)

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 10.67 cycles. At this rate:

12% of peak load performance is reached (12.00 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))

Front-end bottlenecks

Found no such bottlenecks.

ASM code

In the binary file, the address of the loop is: 436048

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	Latency	Recip. throughput	Vectorization
LD1R {V0.2D}, [X6]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
ADD X22, X0, #16	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
ADD X21, X0, #32	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
ADD X12, X0, #48	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
STR Q0, [X11, X0]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V1.2D}, [X5]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q1, [X10, X0]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V2.2D}, [X4]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q2, [X9, X0]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V3.2D}, [X3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q3, [X8, X0]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
ADD X0, X0, #64	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
LD1R {V4.2D}, [X6]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q4, [X11, X22]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V5.2D}, [X5]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q5, [X10, X22]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V6.2D}, [X4]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q6, [X9, X22]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V7.2D}, [X3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q7, [X8, X22]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V16.2D}, [X6]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q16, [X11, X21]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V17.2D}, [X5]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q17, [X10, X21]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V18.2D}, [X4]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q18, [X9, X21]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V19.2D}, [X3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q19, [X8, X21]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V28.2D}, [X6]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q28, [X11, X12]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V29.2D}, [X5]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q29, [X10, X12]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V30.2D}, [X4]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q30, [X9, X12]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V31.2D}, [X3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q31, [X8, X12]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
CMP X14, X0	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.33	N/A
B.NE 436048 <_Z14generate_chunkiR16global_variables._omp_fn.0+0x1e8>	1	0.50	0.50	0	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A

Function	generate_chunk(int, global_variables&) [clone ._omp_fn.0]
Source file and lines	generate_chunk.cpp:77-80
Module	exec

gain
potential
hint
expert

Vectorization

Details

50% of VPU instructions are used in vector version (process two or more data elements in vector registers):

0% of VPU loads are used in vector version.

Since your execution units are vector units, only a fully vectorized loop can use their full power.

Workaround

Try another compiler or update/tune your current one
Remove inter-iterations dependences from your loop and make it unit-stride:
- If your arrays have 2 or more dimensions, check whether elements are accessed contiguously and, otherwise, try to permute loops accordingly: C storage order is row-major: for(i) for(j) a[j][i] = b[j][i]; (slow, non stride 1) => for(i) for(j) a[i][j] = b[i][j]; (fast, stride 1)
- If your loop streams arrays of structures (AoS), try to use structures of arrays instead (SoA): for(i) a[i].x = b[i].x; (slow, non stride 1) => for(i) a.x[i] = b.x[i]; (fast, stride 1)

No data for this section

Slow data structures access

Detected data structures (typically arrays) that cannot be efficiently read/written

Details

Constant non-unit stride: 4 occurrence(s)

Non-unit stride (uncontiguous) accesses are not efficiently using data caches

Workaround

Try to reorganize arrays of structures to structures of arrays
Consider to permute loops (see vectorization gain report)

Matching between your loop (in the source code) and the binary loop

The binary loop does not contain any FP arithmetical operations. The binary loop is loading 128 bytes.

General properties

nb instructions	38
nb uops	38
loop length	152
used w registers	0
used x registers	13
used b registers	0
used h registers	0
used s registers	0
used d registers	0
used q registers	16
used v registers	16
used z registers	0
nb stack references	0

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	4.75 cycles
front end	4.75 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	1.25	1.25	1.25	1.25	8.00	8.00	8.00	8.00	10.67	10.67	10.67	0.00	0.00
cycles	0.50	0.50	1.25	1.25	1.25	1.25	8.00	8.00	8.00	8.00	10.67	10.67	10.67	0.00	0.00

Execution ports to units layout:

P0: BRU
P1: BRU
P2: ALU
P3: ALU
P4: ALU
P5: ALU
P6 (128 bits): VPU, FP store data, ALU, DIV/SQRT
P7 (128 bits): VPU, ALU, FP store data
P8 (128 bits): VPU, ALU, DIV/SQRT
P9 (128 bits): ALU, VPU
P10 (256 bits): store address, load
P11 (256 bits): store address, load
P12 (256 bits): load
P13 (64 bits): store data
P14 (64 bits): store data

Cycles executing div or sqrt instructions	NA
Longest recurrence chain latency (RecMII)	1.00

Cycles summary

Front-end	4.75
Dispatch	10.67
Data deps.	1.00
Overall L1	10.67

Vectorization ratios

all	50%
load	0%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	NA (no add-sub vectorizable/vectorized instructions)
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	NA (no other vectorizable/vectorized instructions)

Vector efficiency ratios

all	37%
load	25%
store	50%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	NA (no add-sub vectorizable/vectorized instructions)
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	NA (no other vectorizable/vectorized instructions)

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 10.67 cycles. At this rate:

12% of peak load performance is reached (12.00 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))

Front-end bottlenecks

Found no such bottlenecks.

ASM code

In the binary file, the address of the loop is: 436048

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	Latency	Recip. throughput	Vectorization
LD1R {V0.2D}, [X6]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
ADD X22, X0, #16	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
ADD X21, X0, #32	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
ADD X12, X0, #48	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
STR Q0, [X11, X0]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V1.2D}, [X5]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q1, [X10, X0]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V2.2D}, [X4]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q2, [X9, X0]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V3.2D}, [X3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q3, [X8, X0]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
ADD X0, X0, #64	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
LD1R {V4.2D}, [X6]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q4, [X11, X22]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V5.2D}, [X5]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q5, [X10, X22]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V6.2D}, [X4]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q6, [X9, X22]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V7.2D}, [X3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q7, [X8, X22]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V16.2D}, [X6]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q16, [X11, X21]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V17.2D}, [X5]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q17, [X10, X21]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V18.2D}, [X4]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q18, [X9, X21]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V19.2D}, [X3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q19, [X8, X21]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V28.2D}, [X6]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q28, [X11, X12]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V29.2D}, [X5]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q29, [X10, X12]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V30.2D}, [X4]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q30, [X9, X12]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
LD1R {V31.2D}, [X3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	8	0.33	scal (25.0%)
STR Q31, [X8, X12]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
CMP X14, X0	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.33	N/A
B.NE 436048 <_Z14generate_chunkiR16global_variables._omp_fn.0+0x1e8>	1	0.50	0.50	0	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A

▶Scalability Runs Description

Run 1x1	Number processes: 1Number nodes: NARun Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_NUM_THREADS: 1OMP_PLACES: threads
Run 1x2	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 2OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads
Run 1x4	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 4OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads
Run 1x8	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 8OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads
Run 1x16	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 16OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads
Run 1x24	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 24OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads
Run 1x32	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 32OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads
Run 1x40	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 40OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads
Run 1x48	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 48OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads
Run 1x56	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 56OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads
Run 1x64	Number processes: 1Run Command: <executable>MPI Command: mpirun -n <number_processes> --bind-to core --map-by package:PE=64 --rank-by fill --report-bindings Dataset: Run Directory: /home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/run/oneview_runs/multicore/gcc_4/oneview_run_1782227431OMP_NUM_THREADS: 64OMP_PROC_BIND: spreadOMP_DISPLAY_AFFINITY: TRUEOMP_AFFINITY_FORMAT: 'OMP: pid %P tid %i thread %n bound to OS proc set {%A}'OMP_DISPLAY_ENV: TRUEOMP_PLACES: threads

(1x1) Efficiency	(1x1) Potential Speed-Up (%)	(1x2) Efficiency	(1x2) Potential Speed-Up (%)	(1x4) Efficiency	(1x4) Potential Speed-Up (%)	(1x8) Efficiency	(1x8) Potential Speed-Up (%)	(1x16) Efficiency	(1x16) Potential Speed-Up (%)	(1x24) Efficiency	(1x24) Potential Speed-Up (%)	(1x32) Efficiency	(1x32) Potential Speed-Up (%)	(1x40) Efficiency	(1x40) Potential Speed-Up (%)	(1x48) Efficiency	(1x48) Potential Speed-Up (%)	(1x56) Efficiency	(1x56) Potential Speed-Up (%)	(1x64) Efficiency	(1x64) Potential Speed-Up (%)
1	0	0.94	0	0.85	0	0.62	0.01	0.33	0.03	0.23	0.04	0.18	0.04	0.15	0.04	0.13	0.04	0.11	0.04	0.1	0.04

Speed-Up and Efficiency

▶Detailed Speed-Up and Efficiency

Run	Number of threads	Efficiency (ideal is 1)	Speedup	Ideal Speedup	Time (s)	Coverage (%)
1x1	1	1	1	1	0.40499997138977	0.027248689904809
1x2	2	0.94	1.88	2	0.21500000357628	0.028761142864823
1x4	4	0.85	3.41	4	0.12000000476837	0.030932011082768
1x8	8	0.62	4.98	8	0.080000005662441	0.037437241524458
1x16	16	0.33	5.27	16	0.075000002980232	0.045649576932192
1x24	24	0.23	5.49	24	0.075000002980232	0.047045528888702
1x32	32	0.18	5.78	32	0.070000007748604	0.048514187335968
1x40	40	0.15	6.18	40	0.065000005066395	0.047856617718935
1x48	48	0.13	6.33	48	0.065000005066395	0.047517105937004
1x56	56	0.11	6.37	56	0.065000005066395	0.047366570681334
1x64	64	0.1	6.37	64	0.065000005066395	0.047225285321474

Report Configuration

Vectorization

Details

Workaround

Slow data structures access

Details

Workaround

Matching between your loop (in the source code) and the binary loop

General properties

Front-end

Back-end

Cycles summary

Vectorization ratios

Vector efficiency ratios

Cycles and memory resources usage

Front-end bottlenecks

ASM code

Vectorization

Details

Workaround

Slow data structures access

Details

Workaround

Matching between your loop (in the source code) and the binary loop

General properties

Front-end

Back-end

Cycles summary

Vectorization ratios

Vector efficiency ratios

Cycles and memory resources usage

Front-end bottlenecks

ASM code

▶Scalability Runs Description

▼Columns Filter

Speed-Up and Efficiency

▶Detailed Speed-Up and Efficiency