OV - exec - Loop 264

0x431780 ST1D	{Z29.D}, P7, [X4, X0,LSL #3]    [5]

0x431784 LD1RD	{Z0.D}, P6/Z, [X6]    [2]

0x431788 ST1D	{Z0.D}, P7, [X3, X0,LSL #3]    [4]

0x43178c LD1D	{Z28.D}, P7/Z, [X5, X0,LSL #3]    [1]

0x431790 ST1D	{Z28.D}, P7, [X2, X0,LSL #3]    [3]

0x431794 ADD	X0, X0, X8

0x431798 WHILELO	P7.D, W0, W1

0x43179c B.NE	431780

/home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/build/CloverLeaf2.0-CXX/src/omp/initialise_chunk.cpp: 80 - 82

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

80:       field.volume(i, j) = dx * dy;

81:       field.xarea(i, j) = field.celldy[j];

82:       field.yarea(i, j) = field.celldx[i];

Coverage (%)	Name	Source Location	Module
►98.50+	omp_fulfill_event		libgomp.so.1.0.0
○	start_thread		libc.so.6
○	thread_start		libc.so.6
►1.50+	GOMP_parallel		libgomp.so.1.0.0
○	initialise_chunk(int, global_v[...]	initialise_chunk.cpp:85	exec
○	start(parallel_&, global_confi[...]	start.cpp:83	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	1.18
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	2.50
Bottlenecks	P10, P11,
Function	initialise_chunk(int, global_variables&) [clone ._omp_fn.4]
Source	initialise_chunk.cpp:80-82
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	2.50
CQA cycles if no scalar integer	2.50
CQA cycles if FP arith vectorized	2.50
CQA cycles if fully vectorized	2.13
Front-end cycles	1.00
P0 cycles	0.50
P1 cycles	0.50
P2 cycles	0.50
P3 cycles	0.25
P4 cycles	1.00
P5 cycles	0.25
P6 cycles	0.75
P7 cycles	0.75
P8 cycles	0.75
P9 cycles	0.75
P10 cycles	2.50
P11 cycles	2.50
P12 cycles	0.00
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	8.00
Nb uops	8.00
Nb loads	NA
Nb stores	3.00
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	51.20
Bytes prefetched	0.00
Bytes loaded	32.00
Bytes stored	96.00
Stride 0	1.00
Stride 1	0.00
Stride n	0.00
Stride unknown	4.00
Stride indirect	0.00
Vectorization ratio all	80.00
Vectorization ratio load	50.00
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	85.00
Vector-efficiency ratio load	62.50
Vector-efficiency ratio store	100.00
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	1.18
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	2.50
Bottlenecks	P10, P11,
Function	initialise_chunk(int, global_variables&) [clone ._omp_fn.4]
Source	initialise_chunk.cpp:80-82
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	2.50
CQA cycles if no scalar integer	2.50
CQA cycles if FP arith vectorized	2.50
CQA cycles if fully vectorized	2.13
Front-end cycles	1.00
P0 cycles	0.50
P1 cycles	0.50
P2 cycles	0.50
P3 cycles	0.25
P4 cycles	1.00
P5 cycles	0.25
P6 cycles	0.75
P7 cycles	0.75
P8 cycles	0.75
P9 cycles	0.75
P10 cycles	2.50
P11 cycles	2.50
P12 cycles	0.00
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	8.00
Nb uops	8.00
Nb loads	NA
Nb stores	3.00
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	51.20
Bytes prefetched	0.00
Bytes loaded	32.00
Bytes stored	96.00
Stride 0	1.00
Stride 1	0.00
Stride n	0.00
Stride unknown	4.00
Stride indirect	0.00
Vectorization ratio all	80.00
Vectorization ratio load	50.00
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	85.00
Vector-efficiency ratio load	62.50
Vector-efficiency ratio store	100.00
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	initialise_chunk(int, global_variables&) [clone ._omp_fn.4]
Source file and lines	initialise_chunk.cpp:80-82
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/initialise_chunk.cpp:80-82.

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

gain
potential
hint
expert

Vectorization

Your loop is partially vectorized. 85% 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 2.50 to 2.12 cycles (1.18x speedup).

Details

80% of VPU instructions are used in vector version (process two or more data elements in vector registers):

50% 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.

No data for this section

Slow data structures access

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

Details

Constant unknown 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 32 bytes. The binary loop is storing 96 bytes.

General properties

nb instructions	8
nb uops	8
loop length	32
used w registers	2
used x registers	7
used b registers	0
used h registers	0
used s registers	0
used d registers	0
used q registers	0
used v registers	0
used z registers	3
nb stack references	0

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	1.00 cycles
front end	1.00 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	0.50	0.25	1.00	0.25	0.75	0.75	0.75	0.75	2.50	2.50	0.00	0.00	0.00
cycles	0.50	0.50	0.50	0.25	1.00	0.25	0.75	0.75	0.75	0.75	2.50	2.50	0.00	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	1.00
Dispatch	2.50
Data deps.	1.00
Overall L1	2.50

Vectorization ratios

all	80%
load	50%
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	85%
load	62%
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)

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 2.50 cycles. At this rate:

13% of peak load performance is reached (12.80 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))
80% of peak store performance is reached (38.40 out of 48.00 bytes stored per cycle (GB/s @ 1GHz))

Front-end bottlenecks

Found no such bottlenecks.

ASM code

In the binary file, the address of the loop is: 431780

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	Latency	Recip. throughput	Vectorization
ST1D {Z29.D}, P7, [X4, X0,LSL #3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	2	0.50	vect (100.0%)
LD1RD {Z0.D}, P6/Z, [X6]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	scal (25.0%)
ST1D {Z0.D}, P7, [X3, X0,LSL #3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	2	0.50	vect (100.0%)
LD1D {Z28.D}, P7/Z, [X5, X0,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
ST1D {Z28.D}, P7, [X2, X0,LSL #3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	2	0.50	vect (100.0%)
ADD X0, X0, X8	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
WHILELO P7.D, W0, W1	1	0	0	0	0	1	0	0	0	0	0	0	0	3	2	N/A
B.NE 431780 <_Z16initialise_chunkiR16global_variables._omp_fn.4+0xf0>	1	0.50	0.50	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A

Function	initialise_chunk(int, global_variables&) [clone ._omp_fn.4]
Source file and lines	initialise_chunk.cpp:80-82
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/initialise_chunk.cpp:80-82.

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

gain
potential
hint
expert

Vectorization

Your loop is partially vectorized. 85% 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 2.50 to 2.12 cycles (1.18x speedup).

Details

80% of VPU instructions are used in vector version (process two or more data elements in vector registers):

50% 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.

No data for this section

Slow data structures access

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

Details

Constant unknown 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 32 bytes. The binary loop is storing 96 bytes.

General properties

nb instructions	8
nb uops	8
loop length	32
used w registers	2
used x registers	7
used b registers	0
used h registers	0
used s registers	0
used d registers	0
used q registers	0
used v registers	0
used z registers	3
nb stack references	0

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	1.00 cycles
front end	1.00 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	0.50	0.25	1.00	0.25	0.75	0.75	0.75	0.75	2.50	2.50	0.00	0.00	0.00
cycles	0.50	0.50	0.50	0.25	1.00	0.25	0.75	0.75	0.75	0.75	2.50	2.50	0.00	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	1.00
Dispatch	2.50
Data deps.	1.00
Overall L1	2.50

Vectorization ratios

all	80%
load	50%
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	85%
load	62%
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)

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 2.50 cycles. At this rate:

13% of peak load performance is reached (12.80 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))
80% of peak store performance is reached (38.40 out of 48.00 bytes stored per cycle (GB/s @ 1GHz))

Front-end bottlenecks

Found no such bottlenecks.

ASM code

In the binary file, the address of the loop is: 431780

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	Latency	Recip. throughput	Vectorization
ST1D {Z29.D}, P7, [X4, X0,LSL #3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	2	0.50	vect (100.0%)
LD1RD {Z0.D}, P6/Z, [X6]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	scal (25.0%)
ST1D {Z0.D}, P7, [X3, X0,LSL #3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	2	0.50	vect (100.0%)
LD1D {Z28.D}, P7/Z, [X5, X0,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
ST1D {Z28.D}, P7, [X2, X0,LSL #3]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	2	0.50	vect (100.0%)
ADD X0, X0, X8	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
WHILELO P7.D, W0, W1	1	0	0	0	0	1	0	0	0	0	0	0	0	3	2	N/A
B.NE 431780 <_Z16initialise_chunkiR16global_variables._omp_fn.4+0xf0>	1	0.50	0.50	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A

Report Configuration

Vectorization

Details

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

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