OV - exec - Loop 173

	Loop Id: 173	Module: exec	Source: advec_cell.cpp:211-216	Coverage: 4.12%

0x42d484 LDR	Q19, [X10, X0]    [6]

0x42d488 ADD	X17, X0, #16

0x42d48c LDR	Q20, [X3, X0]    [9]

0x42d490 LDR	Q21, [X7, X0]    [3]

0x42d494 LDR	Q22, [X6, X0]    [2]

0x42d498 LDR	Q23, [X5, X0]    [1]

0x42d49c FMUL	V24.2D, V20.2D, V19.2D

0x42d4a0 LDR	Q25, [X8, X0]    [4]

0x42d4a4 LDR	Q30, [X2, X0]    [8]

0x42d4a8 FSUB	V0.2D, V21.2D, V22.2D

0x42d4ac LDR	Q1, [X1, X0]    [7]

0x42d4b0 FADD	V28.2D, V23.2D, V19.2D

0x42d4b4 LDR	Q31, [X9, X0]    [5]

0x42d4b8 FSUB	V2.2D, V24.2D, V25.2D

0x42d4bc FMLA	V0.2D, V30.2D, V24.2D

0x42d4c0 FSUB	V29.2D, V28.2D, V1.2D

0x42d4c4 FADD	V3.2D, V2.2D, V31.2D

0x42d4c8 FDIV	V4.2D, V3.2D, V29.2D

0x42d4cc FDIV	V5.2D, V0.2D, V3.2D

0x42d4d0 STR	Q4, [X3, X0]    [9]

0x42d4d4 STR	Q5, [X2, X0]    [8]

0x42d4d8 ADD	X0, X0, #32

0x42d4dc LDR	Q6, [X10, X17]    [6]

0x42d4e0 LDR	Q7, [X3, X17]    [9]

0x42d4e4 LDR	Q27, [X7, X17]    [3]

0x42d4e8 LDR	Q16, [X6, X17]    [2]

0x42d4ec LDR	Q26, [X5, X17]    [1]

0x42d4f0 FMUL	V17.2D, V7.2D, V6.2D

0x42d4f4 LDR	Q18, [X8, X17]    [4]

0x42d4f8 LDR	Q19, [X2, X17]    [8]

0x42d4fc FSUB	V23.2D, V27.2D, V16.2D

0x42d500 LDR	Q20, [X1, X17]    [7]

0x42d504 FADD	V21.2D, V26.2D, V6.2D

0x42d508 LDR	Q22, [X9, X17]    [5]

0x42d50c FSUB	V24.2D, V17.2D, V18.2D

0x42d510 FMLA	V23.2D, V19.2D, V17.2D

0x42d514 FSUB	V25.2D, V21.2D, V20.2D

0x42d518 FADD	V30.2D, V24.2D, V22.2D

0x42d51c FDIV	V0.2D, V30.2D, V25.2D

0x42d520 FDIV	V1.2D, V23.2D, V30.2D

0x42d524 STR	Q0, [X3, X17]    [9]

0x42d528 STR	Q1, [X2, X17]    [8]

0x42d52c CMP	X0, X15

0x42d530 B.NE	42d484

/home/eoseret/qaas/qaas_runs/178-219-7589/intel/CloverLeaf2.0-CXX/build/CloverLeaf2.0-CXX/src/omp/advec_cell.cpp: 211 - 216

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

211:         double pre_mass_s = density1(i, j) * pre_vol(i, j);

212:         double post_mass_s = pre_mass_s + mass_flux_y(i, j) - mass_flux_y(i + 0, j + 1);

213:         double post_ener_s = (energy1(i, j) * pre_mass_s + ener_flux(i, j) - ener_flux(i + 0, j + 1)) / post_mass_s;

214:         double advec_vol_s = pre_vol(i, j) + vol_flux_y(i, j) - vol_flux_y(i + 0, j + 1);

215:         density1(i, j) = post_mass_s / advec_vol_s;

216:         energy1(i, j) = post_ener_s;

Coverage (%)	Name	Module
►98.44+	omp_fulfill_event	libgomp.so.1.0.0
○	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	1.00
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.91 - 3.81
Bottlenecks	P6, P8,
Function	advec_cell_kernel(int, int, int, int, int, int, clover::Buffer1D&, clover::Buffer1D&, 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::Buffer2D&) [clone ._omp_fn.7]
Source	advec_cell.cpp:211-216
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	13.99 - 27.97
CQA cycles if no scalar integer	13.99 - 27.97
CQA cycles if FP arith vectorized	13.99 - 27.97
CQA cycles if fully vectorized	13.99 - 27.97
Front-end cycles	5.50
P0 cycles	0.50
P1 cycles	0.50
P2 cycles	0.75
P3 cycles	0.75
P4 cycles	0.75
P5 cycles	0.75
P6 cycles	5.50
P7 cycles	5.50
P8 cycles	5.50
P9 cycles	5.50
P10 cycles	7.33
P11 cycles	7.33
P12 cycles	7.33
P13 cycles	0.00
P14 cycles	0.00
DIV/SQRT cycles	13.99 - 27.97
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	44.00
Nb uops	44.00
Nb loads	NA
Nb stores	4.00
Nb stack references	0.00
FLOP/cycle	2.86 - 1.43
Nb FLOP add-sub	20.00
Nb FLOP mul	4.00
Nb FLOP fma	4.00
Nb FLOP div	8.00
Nb FLOP rcp	0.00
Nb FLOP sqrt	0.00
Nb FLOP rsqrt	0.00
Bytes/cycle	0.00
Bytes prefetched	0.00
Bytes loaded	0.00
Bytes stored	0.00
Stride 0	0.00
Stride 1	0.00
Stride n	9.00
Stride unknown	0.00
Stride indirect	0.00
Vectorization ratio all	100.00
Vectorization ratio load	100.00
Vectorization ratio store	100.00
Vectorization ratio mul	100.00
Vectorization ratio add_sub	100.00
Vectorization ratio fma	100.00
Vectorization ratio div_sqrt	100.00
Vectorization ratio other	NA
Vector-efficiency ratio all	50.00
Vector-efficiency ratio load	50.00
Vector-efficiency ratio store	50.00
Vector-efficiency ratio mul	50.00
Vector-efficiency ratio add_sub	50.00
Vector-efficiency ratio fma	50.00
Vector-efficiency ratio div_sqrt	50.00
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	1.00
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.91 - 3.81
Bottlenecks	P6, P8,
Function	advec_cell_kernel(int, int, int, int, int, int, clover::Buffer1D&, clover::Buffer1D&, 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::Buffer2D&) [clone ._omp_fn.7]
Source	advec_cell.cpp:211-216
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	13.99 - 27.97
CQA cycles if no scalar integer	13.99 - 27.97
CQA cycles if FP arith vectorized	13.99 - 27.97
CQA cycles if fully vectorized	13.99 - 27.97
Front-end cycles	5.50
P0 cycles	0.50
P1 cycles	0.50
P2 cycles	0.75
P3 cycles	0.75
P4 cycles	0.75
P5 cycles	0.75
P6 cycles	5.50
P7 cycles	5.50
P8 cycles	5.50
P9 cycles	5.50
P10 cycles	7.33
P11 cycles	7.33
P12 cycles	7.33
P13 cycles	0.00
P14 cycles	0.00
DIV/SQRT cycles	13.99 - 27.97
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	44.00
Nb uops	44.00
Nb loads	NA
Nb stores	4.00
Nb stack references	0.00
FLOP/cycle	2.86 - 1.43
Nb FLOP add-sub	20.00
Nb FLOP mul	4.00
Nb FLOP fma	4.00
Nb FLOP div	8.00
Nb FLOP rcp	0.00
Nb FLOP sqrt	0.00
Nb FLOP rsqrt	0.00
Bytes/cycle	0.00
Bytes prefetched	0.00
Bytes loaded	0.00
Bytes stored	0.00
Stride 0	0.00
Stride 1	0.00
Stride n	9.00
Stride unknown	0.00
Stride indirect	0.00
Vectorization ratio all	100.00
Vectorization ratio load	100.00
Vectorization ratio store	100.00
Vectorization ratio mul	100.00
Vectorization ratio add_sub	100.00
Vectorization ratio fma	100.00
Vectorization ratio div_sqrt	100.00
Vectorization ratio other	NA
Vector-efficiency ratio all	50.00
Vector-efficiency ratio load	50.00
Vector-efficiency ratio store	50.00
Vector-efficiency ratio mul	50.00
Vector-efficiency ratio add_sub	50.00
Vector-efficiency ratio fma	50.00
Vector-efficiency ratio div_sqrt	50.00
Vector-efficiency ratio other	NA

Path /

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

Function	advec_cell_kernel(int, int, int, int, int, int, clover::Buffer1D&, clover::Buffer1D&, 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::Buffer2D&) [clone ._omp_fn.7]
Source file and lines	advec_cell.cpp:211-216
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/advec_cell.cpp:211-216.

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

gain
potential
hint
expert

Vectorization

Your loop is vectorized, but using only 128 out of 256 bits (SSE/AVX-128 instructions on AVX/AVX2 processors).

Details

All VPU instructions are used in vector version (process two or more data elements in vector registers).

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 27.97 to 7.33 cycles (3.81x speedup).

FMA

Detected 4 FMA (fused multiply-add) operations. Presence of both ADD/SUB and MUL operations.

Workaround

Try to change order in which elements are evaluated (using parentheses) in arithmetic expressions containing both ADD/SUB and MUL operations to enable your compiler to generate FMA instructions wherever possible. For instance a + b*c is a valid FMA (MUL then ADD). However (a+b)* c cannot be translated into an FMA (ADD then MUL).

Slow data structures access

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

Details

Constant non-unit stride: 9 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 is composed of 40 FP arithmetical operations:

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

The binary loop does not load or store any data.

General properties

nb instructions	44
nb uops	44
loop length	176
used w registers	0
used x registers	12
used b registers	0
used h registers	0
used s registers	0
used d registers	0
used q registers	18
used v registers	24
used z registers	0
nb stack references	0
ADD-SUB / MUL ratio	5.00

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	5.50 cycles
front end	5.50 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	0.75	0.75	0.75	0.75	5.50	5.50	5.50	5.50	7.33	7.33	7.33	0.00	0.00
cycles	0.50	0.50	0.75	0.75	0.75	0.75	5.50	5.50	5.50	5.50	7.33	7.33	7.33	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	13.99-27.97
Longest recurrence chain latency (RecMII)	1.00

Cycles summary

Front-end	5.50
Dispatch	7.33
DIV/SQRT	13.99-27.97
Data deps.	1.00
Overall L1	13.99-27.97

Vectorization ratios

INT

all	100%
load	100%
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)
other	NA (no other vectorizable/vectorized instructions)

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

INT+FP

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

Vector efficiency ratios

INT

all	50%
load	50%
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)
other	NA (no other vectorizable/vectorized instructions)

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

INT+FP

all	50%
load	50%
store	50%
mul	50%
add-sub	50%
fma	50%
div/sqrt	50%
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 27.97 cycles.

Front-end bottlenecks

Found no such bottlenecks.

ASM code

In the binary file, the address of the loop is: 42d484

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	Latency	Recip. throughput	Vectorization
LDR Q19, [X10, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
ADD X17, 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
LDR Q20, [X3, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q21, [X7, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q22, [X6, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q23, [X5, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FMUL V24.2D, V20.2D, V19.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	3	0.25	vect (50.0%)
LDR Q25, [X8, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q30, [X2, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FSUB V0.2D, V21.2D, V22.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
LDR Q1, [X1, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FADD V28.2D, V23.2D, V19.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
LDR Q31, [X9, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FSUB V2.2D, V24.2D, V25.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FMLA V0.2D, V30.2D, V24.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	4	0.25	vect (50.0%)
FSUB V29.2D, V28.2D, V1.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FADD V3.2D, V2.2D, V31.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FDIV V4.2D, V3.2D, V29.2D	1	0	0	0	0	0	0	0.50	0	0.50	0	0	0	0	7-15	3.50-6.99	vect (50.0%)
FDIV V5.2D, V0.2D, V3.2D	1	0	0	0	0	0	0	0.50	0	0.50	0	0	0	0	7-15	3.50-6.99	vect (50.0%)
STR Q4, [X3, 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%)
STR Q5, [X2, 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, #32	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
LDR Q6, [X10, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q7, [X3, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q27, [X7, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q16, [X6, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q26, [X5, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FMUL V17.2D, V7.2D, V6.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	3	0.25	vect (50.0%)
LDR Q18, [X8, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q19, [X2, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FSUB V23.2D, V27.2D, V16.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
LDR Q20, [X1, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FADD V21.2D, V26.2D, V6.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
LDR Q22, [X9, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FSUB V24.2D, V17.2D, V18.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FMLA V23.2D, V19.2D, V17.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	4	0.25	vect (50.0%)
FSUB V25.2D, V21.2D, V20.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FADD V30.2D, V24.2D, V22.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FDIV V0.2D, V30.2D, V25.2D	1	0	0	0	0	0	0	0.50	0	0.50	0	0	0	0	7-15	3.50-6.99	vect (50.0%)
FDIV V1.2D, V23.2D, V30.2D	1	0	0	0	0	0	0	0.50	0	0.50	0	0	0	0	7-15	3.50-6.99	vect (50.0%)
STR Q0, [X3, X17]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
STR Q1, [X2, X17]	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 X0, X15	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 42d484 <_Z17advec_cell_kerneliiiiiiRN6clover8Buffer1DIdEES2_RNS_8Buffer2DIdEES5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_._omp_fn.7+0x264>	1	0.50	0.50	0	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A

Function	advec_cell_kernel(int, int, int, int, int, int, clover::Buffer1D&, clover::Buffer1D&, 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::Buffer2D&) [clone ._omp_fn.7]
Source file and lines	advec_cell.cpp:211-216
Module	exec

gain
potential
hint
expert

Vectorization

Your loop is vectorized, but using only 128 out of 256 bits (SSE/AVX-128 instructions on AVX/AVX2 processors).

Details

All VPU instructions are used in vector version (process two or more data elements in vector registers).

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 27.97 to 7.33 cycles (3.81x speedup).

FMA

Detected 4 FMA (fused multiply-add) operations. Presence of both ADD/SUB and MUL operations.

Workaround

Slow data structures access

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

Details

Constant non-unit stride: 9 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 is composed of 40 FP arithmetical operations:

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

The binary loop does not load or store any data.

General properties

nb instructions	44
nb uops	44
loop length	176
used w registers	0
used x registers	12
used b registers	0
used h registers	0
used s registers	0
used d registers	0
used q registers	18
used v registers	24
used z registers	0
nb stack references	0
ADD-SUB / MUL ratio	5.00

Front-end

MACRO FUSION NOT POSSIBLE FIT IN UOP CACHE

micro-operation queue	5.50 cycles
front end	5.50 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	0.75	0.75	0.75	0.75	5.50	5.50	5.50	5.50	7.33	7.33	7.33	0.00	0.00
cycles	0.50	0.50	0.75	0.75	0.75	0.75	5.50	5.50	5.50	5.50	7.33	7.33	7.33	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	13.99-27.97
Longest recurrence chain latency (RecMII)	1.00

Cycles summary

Front-end	5.50
Dispatch	7.33
DIV/SQRT	13.99-27.97
Data deps.	1.00
Overall L1	13.99-27.97

Vectorization ratios

INT

all	100%
load	100%
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)
other	NA (no other vectorizable/vectorized instructions)

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

INT+FP

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

Vector efficiency ratios

INT

all	50%
load	50%
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)
other	NA (no other vectorizable/vectorized instructions)

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

INT+FP

all	50%
load	50%
store	50%
mul	50%
add-sub	50%
fma	50%
div/sqrt	50%
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 27.97 cycles.

Front-end bottlenecks

Found no such bottlenecks.

ASM code

In the binary file, the address of the loop is: 42d484

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	Latency	Recip. throughput	Vectorization
LDR Q19, [X10, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
ADD X17, 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
LDR Q20, [X3, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q21, [X7, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q22, [X6, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q23, [X5, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FMUL V24.2D, V20.2D, V19.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	3	0.25	vect (50.0%)
LDR Q25, [X8, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q30, [X2, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FSUB V0.2D, V21.2D, V22.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
LDR Q1, [X1, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FADD V28.2D, V23.2D, V19.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
LDR Q31, [X9, X0]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FSUB V2.2D, V24.2D, V25.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FMLA V0.2D, V30.2D, V24.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	4	0.25	vect (50.0%)
FSUB V29.2D, V28.2D, V1.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FADD V3.2D, V2.2D, V31.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FDIV V4.2D, V3.2D, V29.2D	1	0	0	0	0	0	0	0.50	0	0.50	0	0	0	0	7-15	3.50-6.99	vect (50.0%)
FDIV V5.2D, V0.2D, V3.2D	1	0	0	0	0	0	0	0.50	0	0.50	0	0	0	0	7-15	3.50-6.99	vect (50.0%)
STR Q4, [X3, 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%)
STR Q5, [X2, 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, #32	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	0	1	0.25	N/A
LDR Q6, [X10, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q7, [X3, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q27, [X7, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q16, [X6, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q26, [X5, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FMUL V17.2D, V7.2D, V6.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	3	0.25	vect (50.0%)
LDR Q18, [X8, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
LDR Q19, [X2, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FSUB V23.2D, V27.2D, V16.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
LDR Q20, [X1, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FADD V21.2D, V26.2D, V6.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
LDR Q22, [X9, X17]	1	0	0	0	0	0	0	0	0	0	0	0.33	0.33	0.33	6	0.33	vect (50.0%)
FSUB V24.2D, V17.2D, V18.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FMLA V23.2D, V19.2D, V17.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	4	0.25	vect (50.0%)
FSUB V25.2D, V21.2D, V20.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FADD V30.2D, V24.2D, V22.2D	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	2	0.25	vect (50.0%)
FDIV V0.2D, V30.2D, V25.2D	1	0	0	0	0	0	0	0.50	0	0.50	0	0	0	0	7-15	3.50-6.99	vect (50.0%)
FDIV V1.2D, V23.2D, V30.2D	1	0	0	0	0	0	0	0.50	0	0.50	0	0	0	0	7-15	3.50-6.99	vect (50.0%)
STR Q0, [X3, X17]	1	0	0	0	0	0	0	0.50	0.50	0	0	0.50	0.50	0	2	0.50	vect (50.0%)
STR Q1, [X2, X17]	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 X0, X15	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 42d484 <_Z17advec_cell_kerneliiiiiiRN6clover8Buffer1DIdEES2_RNS_8Buffer2DIdEES5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_._omp_fn.7+0x264>	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

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

Expensive FP math instructions/calls

FMA

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