OV - exec - Loop 163

	Loop Id: 163	Module: exec	Source: advec_mom.cpp:147-149 [...]	Coverage: 4.45%

0x42a504 SEL	Z23.D, P1, Z4.D, Z17.D

0x42a508 ADD	X10, X10, X8

0x42a50c SDIVR	Z23.D, P0/M, Z23.D, Z22.D

0x42a510 ADD	Z24.D, Z5.D, Z23.D

0x42a514 MSB	Z23.D, P0/M, Z4.D, Z22.D

0x42a518 ADD	Z22.D, Z22.D, Z16.D

0x42a51c SXTW	Z24.D, P0/M, Z24.D

0x42a520 MOVPRFX	Z28, Z1

0x42a524 MUL	Z28.D, P0/M, Z28.D, Z24.D

0x42a528 MOVPRFX	Z26, Z0

0x42a52c MUL	Z26.D, P0/M, Z26.D, Z24.D

0x42a530 ADD	Z25.D, Z6.D, Z23.D

0x42a534 ADD	Z23.D, Z7.D, Z23.D

0x42a538 ADR	Z29.D, [Z19, Z25.D,SXTW #3]    [13]

0x42a53c ADR	Z27.D, [Z18, Z25.D,SXTW #3]    [11]

0x42a540 ADR	Z23.D, [Z20, Z23.D,SXTW #3]    [1]

0x42a544 ADR	Z28.D, [Z29, Z28.D,LSL #3]    [14]

0x42a548 MOVPRFX	Z29, Z2

0x42a54c MUL	Z29.D, P0/M, Z29.D, Z24.D

0x42a550 ADR	Z26.D, [Z27, Z26.D,LSL #3]    [10]

0x42a554 MUL	Z24.D, P0/M, Z24.D, Z3.D

0x42a558 LD1D	{Z27.D}, P1/Z, [V26.D]    [7]

0x42a55c LD1D	{Z28.D}, P1/Z, [V28.D]    [12]

0x42a560 ADR	Z23.D, [Z23, Z29.D,LSL #3]    [4]

0x42a564 LD1D	{Z23.D}, P1/Z, [V23.D]    [3]

0x42a568 FMLA	Z23.D, P0/M, Z27.D, Z28.D

0x42a56c ADR	Z27.D, [Z20, Z25.D,SXTW #3]    [1]

0x42a570 ADR	Z25.D, [Z21, Z25.D,SXTW #3]    [2]

0x42a574 ADR	Z27.D, [Z27, Z29.D,LSL #3]    [9]

0x42a578 ADR	Z24.D, [Z25, Z24.D,LSL #3]    [6]

0x42a57c LD1D	{Z27.D}, P1/Z, [V27.D]    [8]

0x42a580 FSUB	Z23.D, Z23.D, Z27.D

0x42a584 LD1D	{Z24.D}, P1/Z, [V24.D]    [5]

0x42a588 FDIV	Z23.D, P0/M, Z23.D, Z24.D

0x42a58c ST1D	{Z23.D}, P1, [V26.D]    [7]

0x42a590 WHILELO	P1.D, X10, X9

0x42a594 B.MI	42a504

/home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/build/CloverLeaf2.0-CXX/src/omp/context.h: 69 - 69

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

69:   T &operator()(size_t i, size_t j) const { return data[i + j * sizeX]; }

/home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/build/CloverLeaf2.0-CXX/src/omp/advec_mom.cpp: 147 - 149

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

147:     for (int j = (y_min + 1); j < (y_max + 1 + 2); j++) {

148:       for (int i = (x_min + 1); i < (x_max + 1 + 2); i++) {

149:         vel1(i, j) = (vel1(i, j) * node_mass_pre(i, j) + mom_flux(i - 1, j + 0) - mom_flux(i, j)) / node_mass_post(i, j);

Coverage (%)	Name	Module
►98.43+	__kmp_invoke_microtask	libomp.so
○	__kmp_invoke_task_func	libomp.so
○	__kmp_launch_thread	libomp.so
○	__kmp_launch_worker(void*)	libomp.so
○	start_thread	libc.so.6
○	thread_start	libc.so.6

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	1.37 - 1.00
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	2.43
Bottlenecks	P6, P8,
Function	advec_mom_kernel(int, int, int, int, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer1D&, clover::Buffer1D&, int, int, int) [clone .omp_outlined.13]
Source	context.h:69-69,advec_mom.cpp:147-149
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	14.00 - 34.08
CQA cycles if no scalar integer	14.00 - 34.08
CQA cycles if FP arith vectorized	14.00 - 34.08
CQA cycles if fully vectorized	10.25 - 34.08
Front-end cycles	4.63
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	14.00
P7 cycles	14.00
P8 cycles	3.00
P9 cycles	3.00
P10 cycles	2.17
P11 cycles	1.83
P12 cycles	2.00
P13 cycles	0.00
P14 cycles	0.00
DIV/SQRT cycles	7.87 - 34.08
Inter-iter dependencies cycles	2
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	37.00
Nb uops	37.00
Nb loads	NA
Nb stores	1.00
Nb stack references	0.00
FLOP/cycle	1.14 - 0.47
Nb FLOP add-sub	4.00
Nb FLOP mul	0.00
Nb FLOP fma	4.00
Nb FLOP div	4.00
Nb FLOP rcp	0.00
Nb FLOP sqrt	0.00
Nb FLOP rsqrt	0.00
Bytes/cycle	5.67 - 13.80
Bytes prefetched	0.00
Bytes loaded	161.25
Bytes stored	32.00
Stride 0	0.00
Stride 1	0.00
Stride n	0.00
Stride unknown	10.00
Stride indirect	4.00
Vectorization ratio all	61.76
Vectorization ratio load	33.33
Vectorization ratio store	100.00
Vectorization ratio mul	100.00
Vectorization ratio add_sub	33.33
Vectorization ratio fma	100.00
Vectorization ratio div_sqrt	100.00
Vectorization ratio other	40.00
Vector-efficiency ratio all	77.94
Vector-efficiency ratio load	50.00
Vector-efficiency ratio store	100.00
Vector-efficiency ratio mul	100.00
Vector-efficiency ratio add_sub	50.00
Vector-efficiency ratio fma	100.00
Vector-efficiency ratio div_sqrt	100.00
Vector-efficiency ratio other	100.00

Metric	Value
CQA speedup if no scalar integer	1.00
CQA speedup if FP arith vectorized	1.00
CQA speedup if fully vectorized	1.37 - 1.00
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	2.43
Bottlenecks	P6, P8,
Function	advec_mom_kernel(int, int, int, int, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer1D&, clover::Buffer1D&, int, int, int) [clone .omp_outlined.13]
Source	context.h:69-69,advec_mom.cpp:147-149
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	14.00 - 34.08
CQA cycles if no scalar integer	14.00 - 34.08
CQA cycles if FP arith vectorized	14.00 - 34.08
CQA cycles if fully vectorized	10.25 - 34.08
Front-end cycles	4.63
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	14.00
P7 cycles	14.00
P8 cycles	3.00
P9 cycles	3.00
P10 cycles	2.17
P11 cycles	1.83
P12 cycles	2.00
P13 cycles	0.00
P14 cycles	0.00
DIV/SQRT cycles	7.87 - 34.08
Inter-iter dependencies cycles	2
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	37.00
Nb uops	37.00
Nb loads	NA
Nb stores	1.00
Nb stack references	0.00
FLOP/cycle	1.14 - 0.47
Nb FLOP add-sub	4.00
Nb FLOP mul	0.00
Nb FLOP fma	4.00
Nb FLOP div	4.00
Nb FLOP rcp	0.00
Nb FLOP sqrt	0.00
Nb FLOP rsqrt	0.00
Bytes/cycle	5.67 - 13.80
Bytes prefetched	0.00
Bytes loaded	161.25
Bytes stored	32.00
Stride 0	0.00
Stride 1	0.00
Stride n	0.00
Stride unknown	10.00
Stride indirect	4.00
Vectorization ratio all	61.76
Vectorization ratio load	33.33
Vectorization ratio store	100.00
Vectorization ratio mul	100.00
Vectorization ratio add_sub	33.33
Vectorization ratio fma	100.00
Vectorization ratio div_sqrt	100.00
Vectorization ratio other	40.00
Vector-efficiency ratio all	77.94
Vector-efficiency ratio load	50.00
Vector-efficiency ratio store	100.00
Vector-efficiency ratio mul	100.00
Vector-efficiency ratio add_sub	50.00
Vector-efficiency ratio fma	100.00
Vector-efficiency ratio div_sqrt	100.00
Vector-efficiency ratio other	100.00

Path /

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

Function	advec_mom_kernel(int, int, int, int, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer1D&, clover::Buffer1D&, int, int, int) [clone .omp_outlined.13]
Source file and lines	advec_mom.cpp:147-149
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/context.h:69
/home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/build/CloverLeaf2.0-CXX/src/omp/advec_mom.cpp:147-149

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 77% of vector register length is used (average across all VPU instructions).

Details

61% of VPU instructions are used in vector version (process two or more data elements in vector registers):

33% of VPU loads are used in vector version.
33% of VPU addition or subtraction instructions are used in vector version.
40% of VPU instructions that are not load, store, addition, subtraction nor multiply instructions are used in vector version.

Expensive FP math instructions/calls

Detected performance impact from expensive FP math instructions/calls. By removing/reexpressing them, you can lower the cost of an iteration from 34.08 to 13.00 cycles (2.62x speedup).

FMA

Detected 4 FMA (fused multiply-add) operations.

Slow data structures access

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

Details

Constant unknown stride: 10 occurrence(s)
Irregular (variable stride) or indirect: 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)
Try to remove indirect accesses. If applicable, precompute elements out of the innermost loop.

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

The binary loop is composed of 16 FP arithmetical operations:

8: addition or subtraction (4 inside FMA instructions)
4: multiply (all inside FMA instructions)
4: divide

The binary loop is loading 161 bytes. The binary loop is storing 32 bytes.

Arithmetic intensity

Arithmetic intensity is 0.08 FP operations per loaded or stored byte.

General properties

nb instructions	37
nb uops	37
loop length	148
used w registers	0
used x registers	3
used b registers	0
used h registers	0
used s registers	0
used d registers	0
used q registers	0
used v registers	5
used z registers	22
nb stack references	0

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	4.63 cycles
front end	4.63 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	14.00	14.00	3.00	3.00	2.17	1.83	2.00	0.00	0.00
cycles	0.50	0.50	0.50	0.25	1.00	0.25	14.00	14.00	3.00	3.00	2.17	1.83	2.00	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	7.87-34.08
Longest recurrence chain latency (RecMII)	2.00

Cycles summary

Front-end	4.63
Dispatch	14.00
DIV/SQRT	7.87-34.08
Data deps.	2.00
Overall L1	14.00-34.08

Vectorization ratios

INT

all	58%
load	33%
store	100%
mul	100%
add-sub	28%
fma	100%
other	50%

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

INT+FP

all	61%
load	33%
store	100%
mul	100%
add-sub	33%
fma	100%
div/sqrt	100%
other	40%

Vector efficiency ratios

INT

all	75%
load	50%
store	100%
mul	100%
add-sub	46%
fma	100%
other	100%

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

INT+FP

all	77%
load	50%
store	100%
mul	100%
add-sub	50%
fma	100%
div/sqrt	100%
other	100%

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 34.08 cycles. At this rate:

4% of peak load performance is reached (4.73 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))
1% of peak store performance is reached (0.94 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: 42a504

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	Latency	Recip. throughput	Vectorization
SEL Z23.D, P1, Z4.D, Z17.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
ADD X10, X10, X8	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
SDIVR Z23.D, P0/M, Z23.D, Z22.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	7-20	0.87-20	vect (100.0%)
ADD Z24.D, Z5.D, Z23.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
MSB Z23.D, P0/M, Z4.D, Z22.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
ADD Z22.D, Z22.D, Z16.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
SXTW Z24.D, P0/M, Z24.D	1	0	0	0	0	0	0	0	1	0	0	0	0	0	2	1	vect (100.0%)
MOVPRFX Z28, Z1	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (100.0%)
MUL Z28.D, P0/M, Z28.D, Z24.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
MOVPRFX Z26, Z0	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (100.0%)
MUL Z26.D, P0/M, Z26.D, Z24.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
ADD Z25.D, Z6.D, Z23.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
ADD Z23.D, Z7.D, Z23.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
ADR Z29.D, [Z19, Z25.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z27.D, [Z18, Z25.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z23.D, [Z20, Z23.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z28.D, [Z29, Z28.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
MOVPRFX Z29, Z2	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (100.0%)
MUL Z29.D, P0/M, Z29.D, Z24.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
ADR Z26.D, [Z27, Z26.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
MUL Z24.D, P0/M, Z24.D, Z3.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
LD1D {Z27.D}, P1/Z, [V26.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
LD1D {Z28.D}, P1/Z, [V28.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
ADR Z23.D, [Z23, Z29.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
LD1D {Z23.D}, P1/Z, [V23.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
FMLA Z23.D, P0/M, Z27.D, Z28.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	4	0.50	vect (100.0%)
ADR Z27.D, [Z20, Z25.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z25.D, [Z21, Z25.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z27.D, [Z27, Z29.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z24.D, [Z25, Z24.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
LD1D {Z27.D}, P1/Z, [V27.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
FSUB Z23.D, Z23.D, Z27.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
LD1D {Z24.D}, P1/Z, [V24.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
FDIV Z23.D, P0/M, Z23.D, Z24.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	7-15	6.99-14.08	vect (100.0%)
ST1D {Z23.D}, P1, [V26.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	6	2	vect (100.0%)
WHILELO P1.D, X10, X9	1	0	0	0	0	1	0	0	0	0	0	0	0	0	3	2	N/A
B.MI 42a504 <_Z16advec_mom_kerneliiiiRN6clover8Buffer2DIdEES2_S2_S2_S2_S2_S2_S2_S2_S2_S2_S2_S2_RNS_8Buffer1DIdEES5_iii.omp_outlined.13+0x124>	1	0.50	0.50	0	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A

Function	advec_mom_kernel(int, int, int, int, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer2D&, clover::Buffer1D&, clover::Buffer1D&, int, int, int) [clone .omp_outlined.13]
Source file and lines	advec_mom.cpp:147-149
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/context.h:69
/home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/build/CloverLeaf2.0-CXX/src/omp/advec_mom.cpp:147-149

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 77% of vector register length is used (average across all VPU instructions).

Details

61% of VPU instructions are used in vector version (process two or more data elements in vector registers):

33% of VPU loads are used in vector version.
33% of VPU addition or subtraction instructions are used in vector version.
40% of VPU instructions that are not load, store, addition, subtraction nor multiply instructions are used in vector version.

Expensive FP math instructions/calls

Detected performance impact from expensive FP math instructions/calls. By removing/reexpressing them, you can lower the cost of an iteration from 34.08 to 13.00 cycles (2.62x speedup).

FMA

Detected 4 FMA (fused multiply-add) operations.

Slow data structures access

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

Details

Constant unknown stride: 10 occurrence(s)
Irregular (variable stride) or indirect: 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)
Try to remove indirect accesses. If applicable, precompute elements out of the innermost loop.

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

The binary loop is composed of 16 FP arithmetical operations:

8: addition or subtraction (4 inside FMA instructions)
4: multiply (all inside FMA instructions)
4: divide

The binary loop is loading 161 bytes. The binary loop is storing 32 bytes.

Arithmetic intensity

Arithmetic intensity is 0.08 FP operations per loaded or stored byte.

General properties

nb instructions	37
nb uops	37
loop length	148
used w registers	0
used x registers	3
used b registers	0
used h registers	0
used s registers	0
used d registers	0
used q registers	0
used v registers	5
used z registers	22
nb stack references	0

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	4.63 cycles
front end	4.63 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	14.00	14.00	3.00	3.00	2.17	1.83	2.00	0.00	0.00
cycles	0.50	0.50	0.50	0.25	1.00	0.25	14.00	14.00	3.00	3.00	2.17	1.83	2.00	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	7.87-34.08
Longest recurrence chain latency (RecMII)	2.00

Cycles summary

Front-end	4.63
Dispatch	14.00
DIV/SQRT	7.87-34.08
Data deps.	2.00
Overall L1	14.00-34.08

Vectorization ratios

INT

all	58%
load	33%
store	100%
mul	100%
add-sub	28%
fma	100%
other	50%

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

INT+FP

all	61%
load	33%
store	100%
mul	100%
add-sub	33%
fma	100%
div/sqrt	100%
other	40%

Vector efficiency ratios

INT

all	75%
load	50%
store	100%
mul	100%
add-sub	46%
fma	100%
other	100%

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

INT+FP

all	77%
load	50%
store	100%
mul	100%
add-sub	50%
fma	100%
div/sqrt	100%
other	100%

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 34.08 cycles. At this rate:

4% of peak load performance is reached (4.73 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))
1% of peak store performance is reached (0.94 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: 42a504

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	Latency	Recip. throughput	Vectorization
SEL Z23.D, P1, Z4.D, Z17.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
ADD X10, X10, X8	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
SDIVR Z23.D, P0/M, Z23.D, Z22.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	7-20	0.87-20	vect (100.0%)
ADD Z24.D, Z5.D, Z23.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
MSB Z23.D, P0/M, Z4.D, Z22.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
ADD Z22.D, Z22.D, Z16.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
SXTW Z24.D, P0/M, Z24.D	1	0	0	0	0	0	0	0	1	0	0	0	0	0	2	1	vect (100.0%)
MOVPRFX Z28, Z1	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (100.0%)
MUL Z28.D, P0/M, Z28.D, Z24.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
MOVPRFX Z26, Z0	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (100.0%)
MUL Z26.D, P0/M, Z26.D, Z24.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
ADD Z25.D, Z6.D, Z23.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
ADD Z23.D, Z7.D, Z23.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
ADR Z29.D, [Z19, Z25.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z27.D, [Z18, Z25.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z23.D, [Z20, Z23.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z28.D, [Z29, Z28.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
MOVPRFX Z29, Z2	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (100.0%)
MUL Z29.D, P0/M, Z29.D, Z24.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
ADR Z26.D, [Z27, Z26.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
MUL Z24.D, P0/M, Z24.D, Z3.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	5	2	vect (100.0%)
LD1D {Z27.D}, P1/Z, [V26.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
LD1D {Z28.D}, P1/Z, [V28.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
ADR Z23.D, [Z23, Z29.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
LD1D {Z23.D}, P1/Z, [V23.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
FMLA Z23.D, P0/M, Z27.D, Z28.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	4	0.50	vect (100.0%)
ADR Z27.D, [Z20, Z25.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z25.D, [Z21, Z25.D,SXTW #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z27.D, [Z27, Z29.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
ADR Z24.D, [Z25, Z24.D,LSL #3]	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	scal (25.0%)
LD1D {Z27.D}, P1/Z, [V27.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
FSUB Z23.D, Z23.D, Z27.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	0	2	0.50	vect (100.0%)
LD1D {Z24.D}, P1/Z, [V24.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.33	0.33	0.33	9	2	vect (100.0%)
FDIV Z23.D, P0/M, Z23.D, Z24.D	1	0	0	0	0	0	0	1	0	0	0	0	0	0	7-15	6.99-14.08	vect (100.0%)
ST1D {Z23.D}, P1, [V26.D]	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	6	2	vect (100.0%)
WHILELO P1.D, X10, X9	1	0	0	0	0	1	0	0	0	0	0	0	0	0	3	2	N/A
B.MI 42a504 <_Z16advec_mom_kerneliiiiRN6clover8Buffer2DIdEES2_S2_S2_S2_S2_S2_S2_S2_S2_S2_S2_S2_RNS_8Buffer1DIdEES5_iii.omp_outlined.13+0x124>	1	0.50	0.50	0	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A

Report Configuration

Vectorization

Details

Expensive FP math instructions/calls

FMA

Slow data structures access

Details

Workaround

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

Arithmetic intensity

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

Expensive FP math instructions/calls

FMA

Slow data structures access

Details

Workaround

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

Arithmetic intensity

General properties

Front-end

Back-end

Cycles summary

Vectorization ratios

Vector efficiency ratios

Cycles and memory resources usage

Front-end bottlenecks

ASM code