OV - exec - Loop 152

	Loop Id: 152	Module: exec	Source: advec_mom_kernel.f90:246-248	Coverage: 4.64%

0x41d600 SBFM	X1, X18, #0, #31

0x41d604 ADD	W0, W0, W13

0x41d608 ADD	W18, W18, W13

0x41d60c SUB	X1, X1, X24

0x41d610 ADD	X2, X1, X16

0x41d614 LD1D	{Z2.D}, P2/Z, [X17, X1,LSL #3]    [2]

0x41d618 LD1D	{Z0.D}, P2/Z, [X20, X2,LSL #3]    [3]

0x41d61c LD1D	{Z1.D}, P2/Z, [X21, X2,LSL #3]    [4]

0x41d620 FMAD	Z0.D, P1/M, Z1.D, Z2.D

0x41d624 LD1D	{Z1.D}, P2/Z, [X22, X2,LSL #3]    [5]

0x41d628 FSUB	Z0.D, Z0.D, Z1.D

0x41d62c LD1D	{Z1.D}, P2/Z, [X23, X2,LSL #3]    [1]

0x41d630 FDIV	Z0.D, P1/M, Z0.D, Z1.D

0x41d634 ST1D	{Z0.D}, P2, [X20, X2,LSL #3]    [3]

0x41d638 WHILELO	P2.D, W0, W14

0x41d63c B.MI	41d600

/home/eoseret/qaas/qaas_runs/178-231-1255/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/advec_mom_kernel.f90: 246 - 248

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

246:       !$OMP SIMD

247:         DO j=x_min,x_max+1

248:           vel1 (j,k)=(vel1(j,k)*node_mass_pre(j,k)+mom_flux(j,k-1)-mom_flux(j,k))/node_mass_post(j,k)

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	1.00
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	2.33 - 4.69
Bottlenecks	P6, P8,
Function	_QMadvec_mom_kernel_modPadvec_mom_kernel..omp_par
Source	advec_mom_kernel.f90:246-248
Source loop unroll info	unrolled by 4
Source loop unroll confidence level	max
Unroll/vectorization loop type	NA
Unroll factor	4
CQA cycles	6.99 - 14.08
CQA cycles if no scalar integer	6.99 - 14.08
CQA cycles if FP arith vectorized	6.99 - 14.08
CQA cycles if fully vectorized	6.99 - 14.08
Front-end cycles	2.00
P0 cycles	0.50
P1 cycles	0.50
P2 cycles	1.50
P3 cycles	1.50
P4 cycles	1.50
P5 cycles	1.50
P6 cycles	1.50
P7 cycles	1.50
P8 cycles	1.00
P9 cycles	1.00
P10 cycles	3.00
P11 cycles	3.00
P12 cycles	0.00
P13 cycles	0.00
P14 cycles	0.00
DIV/SQRT cycles	6.99 - 14.08
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	16.00
Nb uops	16.00
Nb loads	NA
Nb stores	1.00
Nb stack references	0.00
FLOP/cycle	2.29 - 1.14
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	13.63 - 27.46
Bytes prefetched	0.00
Bytes loaded	160.00
Bytes stored	32.00
Stride 0	0.00
Stride 1	0.00
Stride n	0.00
Stride unknown	0.00
Stride indirect	5.00
Vectorization ratio all	90.00
Vectorization ratio load	100.00
Vectorization ratio store	100.00
Vectorization ratio mul	NA
Vectorization ratio add_sub	50.00
Vectorization ratio fma	100.00
Vectorization ratio div_sqrt	100.00
Vectorization ratio other	NA
Vector-efficiency ratio all	91.25
Vector-efficiency ratio load	100.00
Vector-efficiency ratio store	100.00
Vector-efficiency ratio mul	NA
Vector-efficiency ratio add_sub	56.25
Vector-efficiency ratio fma	100.00
Vector-efficiency ratio div_sqrt	100.00
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	2.33 - 4.69
Bottlenecks	P6, P8,
Function	_QMadvec_mom_kernel_modPadvec_mom_kernel..omp_par
Source	advec_mom_kernel.f90:246-248
Source loop unroll info	unrolled by 4
Source loop unroll confidence level	max
Unroll/vectorization loop type	NA
Unroll factor	4
CQA cycles	6.99 - 14.08
CQA cycles if no scalar integer	6.99 - 14.08
CQA cycles if FP arith vectorized	6.99 - 14.08
CQA cycles if fully vectorized	6.99 - 14.08
Front-end cycles	2.00
P0 cycles	0.50
P1 cycles	0.50
P2 cycles	1.50
P3 cycles	1.50
P4 cycles	1.50
P5 cycles	1.50
P6 cycles	1.50
P7 cycles	1.50
P8 cycles	1.00
P9 cycles	1.00
P10 cycles	3.00
P11 cycles	3.00
P12 cycles	0.00
P13 cycles	0.00
P14 cycles	0.00
DIV/SQRT cycles	6.99 - 14.08
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	16.00
Nb uops	16.00
Nb loads	NA
Nb stores	1.00
Nb stack references	0.00
FLOP/cycle	2.29 - 1.14
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	13.63 - 27.46
Bytes prefetched	0.00
Bytes loaded	160.00
Bytes stored	32.00
Stride 0	0.00
Stride 1	0.00
Stride n	0.00
Stride unknown	0.00
Stride indirect	5.00
Vectorization ratio all	90.00
Vectorization ratio load	100.00
Vectorization ratio store	100.00
Vectorization ratio mul	NA
Vectorization ratio add_sub	50.00
Vectorization ratio fma	100.00
Vectorization ratio div_sqrt	100.00
Vectorization ratio other	NA
Vector-efficiency ratio all	91.25
Vector-efficiency ratio load	100.00
Vector-efficiency ratio store	100.00
Vector-efficiency ratio mul	NA
Vector-efficiency ratio add_sub	56.25
Vector-efficiency ratio fma	100.00
Vector-efficiency ratio div_sqrt	100.00
Vector-efficiency ratio other	NA

Path /

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

Function	_QMadvec_mom_kernel_modPadvec_mom_kernel..omp_par
Source file and lines	advec_mom_kernel.f90:246-248
Module	exec

The loop is defined in /home/eoseret/qaas/qaas_runs/178-231-1255/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/advec_mom_kernel.f90:246-248.

The related source loop is unrolled by 4 (including vectorization).

gain
potential
hint
expert

Vectorization

Your loop is highly vectorized. 91% of vector register length is used (average across all VPU instructions).

Details

90% of VPU instructions are used in vector version (process two or more data elements in vector registers):

50% of VPU addition or subtraction 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 14.08 to 3.00 cycles (4.69x 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

Irregular (variable stride) or indirect: 5 occurrence(s)

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

Workaround

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 160 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	16
nb uops	16
loop length	64
used w registers	4
used x registers	10
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	2.00 cycles
front end	2.00 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	1.50	1.50	1.50	1.50	1.50	1.50	0.50	0.50	3.00	3.00	0.00	0.00	0.00
cycles	0.50	0.50	1.50	1.50	1.50	1.50	1.50	1.50	1.00	1.00	3.00	3.00	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	6.99-14.08
Longest recurrence chain latency (RecMII)	1.00

Cycles summary

Front-end	2.00
Dispatch	3.00
DIV/SQRT	6.99-14.08
Data deps.	1.00
Overall L1	6.99-14.08

Vectorization ratios

INT

all	85%
load	100%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	0%
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	NA (no mul vectorizable/vectorized instructions)
add-sub	100%
fma	100%
div/sqrt	100%
other	NA (no other vectorizable/vectorized instructions)

INT+FP

all	90%
load	100%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	50%
fma	100%
div/sqrt	100%
other	NA (no other vectorizable/vectorized instructions)

Vector efficiency ratios

INT

all	87%
load	100%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	12%
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	NA (no mul vectorizable/vectorized instructions)
add-sub	100%
fma	100%
div/sqrt	100%
other	NA (no other vectorizable/vectorized instructions)

INT+FP

all	91%
load	100%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	56%
fma	100%
div/sqrt	100%
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 14.08 cycles. At this rate:

11% of peak load performance is reached (11.36 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))
4% of peak store performance is reached (2.27 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: 41d600

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	Latency	Recip. throughput	Vectorization
SBFM X1, X18, #0, #31	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
ADD W0, W0, W13	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
ADD W18, W18, W13	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	scal (12.5%)
SUB X1, X1, X24	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
ADD X2, X1, X16	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
LD1D {Z2.D}, P2/Z, [X17, X1,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
LD1D {Z0.D}, P2/Z, [X20, X2,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
LD1D {Z1.D}, P2/Z, [X21, X2,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
FMAD Z0.D, P1/M, Z1.D, Z2.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	4	0.50	vect (100.0%)
LD1D {Z1.D}, P2/Z, [X22, X2,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
FSUB Z0.D, Z0.D, Z1.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	2	0.50	vect (100.0%)
LD1D {Z1.D}, P2/Z, [X23, X2,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
FDIV Z0.D, P1/M, Z0.D, Z1.D	1	0	0	0	0	0	0	1	0	0	0	0	0	7-15	6.99-14.08	vect (100.0%)
ST1D {Z0.D}, P2, [X20, X2,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%)
WHILELO P2.D, W0, W14	1	0	0	0	0	1	0	0	0	0	0	0	0	3	2	N/A
B.MI 41d600 <_QMadvec_mom_kernel_modPadvec_mom_kernel..omp_par+0x12d0>	1	0.50	0.50	0	0	0	0	0	0	0	0	0	0	1	0.50	N/A

Function	_QMadvec_mom_kernel_modPadvec_mom_kernel..omp_par
Source file and lines	advec_mom_kernel.f90:246-248
Module	exec

gain
potential
hint
expert

Vectorization

Your loop is highly vectorized. 91% of vector register length is used (average across all VPU instructions).

Details

90% of VPU instructions are used in vector version (process two or more data elements in vector registers):

50% of VPU addition or subtraction 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 14.08 to 3.00 cycles (4.69x 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

Irregular (variable stride) or indirect: 5 occurrence(s)

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

Workaround

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 160 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	16
nb uops	16
loop length	64
used w registers	4
used x registers	10
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	2.00 cycles
front end	2.00 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14
uops	0.50	0.50	1.50	1.50	1.50	1.50	1.50	1.50	0.50	0.50	3.00	3.00	0.00	0.00	0.00
cycles	0.50	0.50	1.50	1.50	1.50	1.50	1.50	1.50	1.00	1.00	3.00	3.00	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	6.99-14.08
Longest recurrence chain latency (RecMII)	1.00

Cycles summary

Front-end	2.00
Dispatch	3.00
DIV/SQRT	6.99-14.08
Data deps.	1.00
Overall L1	6.99-14.08

Vectorization ratios

INT

all	85%
load	100%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	0%
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	NA (no mul vectorizable/vectorized instructions)
add-sub	100%
fma	100%
div/sqrt	100%
other	NA (no other vectorizable/vectorized instructions)

INT+FP

all	90%
load	100%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	50%
fma	100%
div/sqrt	100%
other	NA (no other vectorizable/vectorized instructions)

Vector efficiency ratios

INT

all	87%
load	100%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	12%
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	NA (no mul vectorizable/vectorized instructions)
add-sub	100%
fma	100%
div/sqrt	100%
other	NA (no other vectorizable/vectorized instructions)

INT+FP

all	91%
load	100%
store	100%
mul	NA (no mul vectorizable/vectorized instructions)
add-sub	56%
fma	100%
div/sqrt	100%
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 14.08 cycles. At this rate:

11% of peak load performance is reached (11.36 out of 96.00 bytes loaded per cycle (GB/s @ 1GHz))
4% of peak store performance is reached (2.27 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: 41d600

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	Latency	Recip. throughput	Vectorization
SBFM X1, X18, #0, #31	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
ADD W0, W0, W13	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
ADD W18, W18, W13	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	scal (12.5%)
SUB X1, X1, X24	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
ADD X2, X1, X16	1	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	1	0.25	N/A
LD1D {Z2.D}, P2/Z, [X17, X1,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
LD1D {Z0.D}, P2/Z, [X20, X2,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
LD1D {Z1.D}, P2/Z, [X21, X2,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
FMAD Z0.D, P1/M, Z1.D, Z2.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	4	0.50	vect (100.0%)
LD1D {Z1.D}, P2/Z, [X22, X2,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
FSUB Z0.D, Z0.D, Z1.D	1	0	0	0	0	0	0	0.50	0.50	0	0	0	0	2	0.50	vect (100.0%)
LD1D {Z1.D}, P2/Z, [X23, X2,LSL #3]	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	6	0.50	vect (100.0%)
FDIV Z0.D, P1/M, Z0.D, Z1.D	1	0	0	0	0	0	0	1	0	0	0	0	0	7-15	6.99-14.08	vect (100.0%)
ST1D {Z0.D}, P2, [X20, X2,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%)
WHILELO P2.D, W0, W14	1	0	0	0	0	1	0	0	0	0	0	0	0	3	2	N/A
B.MI 41d600 <_QMadvec_mom_kernel_modPadvec_mom_kernel..omp_par+0x12d0>	1	0.50	0.50	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