OV - exec - Loop 178

	Loop Id: 178	Module: exec	Source: flux_calc_kernel.f90:58-60	Coverage: 4.23%

0x42dfda VMOVUPD	(%RSI,%R10,1),%ZMM0    [12]

0x42dfe1 VADDPD	(%RDI,%R10,1),%ZMM0,%ZMM0    [6]

0x42dfe8 VMULSD	(%R9),%XMM2,%XMM25    [3]

0x42dfee VBROADCASTSD	%XMM25,%ZMM29

0x42dff4 VADDPD	(%R14,%R10,1),%ZMM0,%ZMM0    [5]

0x42dffb VMULPD	(%R8,%R10,1),%ZMM29,%ZMM30    [1]

0x42e002 VMOVQ	%XMM28,%R11

0x42e008 VADDPD	(%R13,%R10,1),%ZMM0,%ZMM0    [4]

0x42e010 VMOVQ	%XMM7,%RDX

0x42e015 VMULPD	%ZMM30,%ZMM0,%ZMM0

0x42e01b VMOVUPD	%ZMM0,(%RCX,%R10,1)    [15]

0x42e022 VMOVUPD	(%R12,%R10,1),%ZMM0    [11]

0x42e029 VADDPD	(%RBX,%R10,1),%ZMM0,%ZMM0    [13]

0x42e030 VMULSD	(%R9),%XMM2,%XMM23    [3]

0x42e036 VADDPD	(%R11,%R10,1),%ZMM0,%ZMM0    [2]

0x42e03d VBROADCASTSD	%XMM23,%ZMM24

0x42e043 VMULPD	(%R15,%R10,1),%ZMM24,%ZMM25    [7]

0x42e04a VADDPD	(%RDX,%R10,1),%ZMM0,%ZMM0    [8]

0x42e051 VMULPD	%ZMM25,%ZMM0,%ZMM0

0x42e057 VMOVUPD	%ZMM0,(%RAX,%R10,1)    [10]

0x42e05e VMOVUPD	0x40(%RSI,%R10,1),%ZMM0    [12]

0x42e066 VADDPD	0x40(%RDI,%R10,1),%ZMM0,%ZMM0    [6]

0x42e06e VMULSD	(%R9),%XMM2,%XMM29    [3]

0x42e074 VADDPD	0x40(%R14,%R10,1),%ZMM0,%ZMM0    [5]

0x42e07c VBROADCASTSD	%XMM29,%ZMM30

0x42e082 VMULPD	0x40(%R8,%R10,1),%ZMM30,%ZMM23    [1]

0x42e08a VADDPD	0x40(%R13,%R10,1),%ZMM0,%ZMM0    [4]

0x42e092 VMULPD	%ZMM23,%ZMM0,%ZMM0

0x42e098 VMOVUPD	%ZMM0,0x40(%RCX,%R10,1)    [15]

0x42e0a0 VMOVUPD	0x40(%R12,%R10,1),%ZMM0    [11]

0x42e0a8 VADDPD	0x40(%RBX,%R10,1),%ZMM0,%ZMM0    [13]

0x42e0b0 VMULSD	(%R9),%XMM2,%XMM24    [3]

0x42e0b6 VADDPD	0x40(%R11,%R10,1),%ZMM0,%ZMM0    [2]

0x42e0be VBROADCASTSD	%XMM24,%ZMM25

0x42e0c4 VMULPD	0x40(%R10,%R15,1),%ZMM25,%ZMM29    [9]

0x42e0cc MOV	0x170(%RSP),%R11    [14]

0x42e0d4 VADDPD	0x40(%RDX,%R10,1),%ZMM0,%ZMM0    [8]

0x42e0dc VMULPD	%ZMM29,%ZMM0,%ZMM0

0x42e0e2 VMOVUPD	%ZMM0,0x40(%RAX,%R10,1)    [10]

0x42e0ea SUB	$-0x80,%R10

0x42e0ee CMP	%R11,%R10

0x42e0f1 JNE	42dfda

/home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90: 58 - 60

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

58:           *(xvel0(j,k)+xvel0(j,k+1)+xvel1(j,k)+xvel1(j,k+1))

59:         vol_flux_y(j,k)=0.25_8*dt*yarea(j,k)                  &

60:           *(yvel0(j,k)+yvel0(j+1,k)+yvel1(j,k)+yvel1(j+1,k))

Coverage (%)	Name	Source Location	Module
►95.69+	gomp_thread_start	team.c:130	libgomp.so.1.0.0
○	start_thread		libc.so.6
○	__GI___clone3		libc.so.6
►4.20+	GOMP_parallel	libgomp.h:982	libgomp.so.1.0.0
○	flux_calc_kernel	flux_calc_kernel.f90:49	exec
○	flux_calc	flux_calc.f90:41	exec
○	hydro	hydro.f90:62	exec
○	main	clover_leaf.f90:41	exec
○	__libc_start_call_main		libc.so.6
○	__libc_start_main		libc.so.6
○	_start	clover_leaf.f90:41	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	1.03
CQA speedup if fully vectorized	1.18
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.03
Bottlenecks	P10, P11,
Function	__flux_calc_kernel_module_MOD_flux_calc_kernel._omp_fn.0
Source	flux_calc_kernel.f90:58-60
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	7.50
CQA cycles if no scalar integer	7.50
CQA cycles if FP arith vectorized	7.25
CQA cycles if fully vectorized	6.38
Front-end cycles	5.13
P0 cycles	0.33
P1 cycles	0.33
P2 cycles	0.33
P3 cycles	0.33
P4 cycles	0.33
P5 cycles	0.33
P6 cycles	7.25
P7 cycles	7.25
P8 cycles	7.25
P9 cycles	7.25
P10 cycles	7.50
P11 cycles	7.50
P12 cycles	6.50
P13 cycles	6.50
P14 cycles	3.00
P15 cycles	3.00
DIV/SQRT cycles	0.00
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	42.00
Nb uops	41.00
Nb loads	25.00
Nb stores	4.00
Nb stack references	1.00
FLOP/cycle	21.87
Nb FLOP add-sub	96.00
Nb FLOP mul	68.00
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	210.13
Bytes prefetched	0.00
Bytes loaded	1320.00
Bytes stored	256.00
Stride 0	2.00
Stride 1	11.00
Stride n	2.00
Stride unknown	0.00
Stride indirect	0.00
Vectorization ratio all	73.68
Vectorization ratio load	83.33
Vectorization ratio store	100.00
Vectorization ratio mul	66.67
Vectorization ratio add_sub	100.00
Vectorization ratio fma	NA
Vectorization ratio div_sqrt	NA
Vectorization ratio other	0.00
Vector-efficiency ratio all	76.97
Vector-efficiency ratio load	85.42
Vector-efficiency ratio store	100.00
Vector-efficiency ratio mul	70.83
Vector-efficiency ratio add_sub	100.00
Vector-efficiency ratio fma	NA
Vector-efficiency ratio div_sqrt	NA
Vector-efficiency ratio other	12.50

Metric	Value
CQA speedup if no scalar integer	1.00
CQA speedup if FP arith vectorized	1.03
CQA speedup if fully vectorized	1.18
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.03
Bottlenecks	P10, P11,
Function	__flux_calc_kernel_module_MOD_flux_calc_kernel._omp_fn.0
Source	flux_calc_kernel.f90:58-60
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	7.50
CQA cycles if no scalar integer	7.50
CQA cycles if FP arith vectorized	7.25
CQA cycles if fully vectorized	6.38
Front-end cycles	5.13
P0 cycles	0.33
P1 cycles	0.33
P2 cycles	0.33
P3 cycles	0.33
P4 cycles	0.33
P5 cycles	0.33
P6 cycles	7.25
P7 cycles	7.25
P8 cycles	7.25
P9 cycles	7.25
P10 cycles	7.50
P11 cycles	7.50
P12 cycles	6.50
P13 cycles	6.50
P14 cycles	3.00
P15 cycles	3.00
DIV/SQRT cycles	0.00
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	42.00
Nb uops	41.00
Nb loads	25.00
Nb stores	4.00
Nb stack references	1.00
FLOP/cycle	21.87
Nb FLOP add-sub	96.00
Nb FLOP mul	68.00
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	210.13
Bytes prefetched	0.00
Bytes loaded	1320.00
Bytes stored	256.00
Stride 0	2.00
Stride 1	11.00
Stride n	2.00
Stride unknown	0.00
Stride indirect	0.00
Vectorization ratio all	73.68
Vectorization ratio load	83.33
Vectorization ratio store	100.00
Vectorization ratio mul	66.67
Vectorization ratio add_sub	100.00
Vectorization ratio fma	NA
Vectorization ratio div_sqrt	NA
Vectorization ratio other	0.00
Vector-efficiency ratio all	76.97
Vector-efficiency ratio load	85.42
Vector-efficiency ratio store	100.00
Vector-efficiency ratio mul	70.83
Vector-efficiency ratio add_sub	100.00
Vector-efficiency ratio fma	NA
Vector-efficiency ratio div_sqrt	NA
Vector-efficiency ratio other	12.50

Path /

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

Function	__flux_calc_kernel_module_MOD_flux_calc_kernel._omp_fn.0
Source file and lines	flux_calc_kernel.f90:58-60
Module	exec

The loop is defined in /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:58-60.

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 76% of vector register length is used (average across all SSE/AVX instructions). By fully vectorizing your loop, you can lower the cost of an iteration from 7.50 to 6.37 cycles (1.18x speedup).

Details

73% of SSE/AVX instructions are used in vector version (process two or more data elements in vector registers):

83% of SSE/AVX loads are used in vector version.
66% of SSE/AVX multiply instructions are used in vector version.
0% of SSE/AVX instructions that are not load, store, addition, subtraction nor multiply instructions 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:
- recompile with fassociative-math (included in Ofast or ffast-math) to extend loop vectorization to FP reductions.
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: Fortran storage order is column-major: do i do j a(i,j) = b(i,j) (slow, non stride 1) => do i do j a(j,i) = b(i,j) (fast, stride 1)
- If your loop streams arrays of structures (AoS), try to use structures of arrays instead (SoA): do i a(i)%x = b(i)%x (slow, non stride 1) => do i a%x(i) = b%x(i) (fast, stride 1)

Execution units bottlenecks

Performance is limited by execution of FP multiply or FMA (fused multiply-add) operations (the FP multiply/FMA unit is a bottleneck).

Workaround

Reduce the number of FP multiply/FMA instructions

FMA

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: 2 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)

Vector unaligned load/store instructions

Detected 8 optimal vector unaligned load/store instructions.

Details

VMOVUPD: 8 occurrences►
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:58
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:58
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:60
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:60
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:58
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:58
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:60
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:60

Workaround

Use vector aligned instructions:

The GNU Fortran compiler does not support allocation alignment and does not feature directives to benefit from aligned data.
Use another compiler or locally use C code (for instance via libraries)

Type of elements and instruction set

4 SSE or AVX instructions are processing arithmetic or math operations on double precision FP elements in scalar mode (one at a time). 20 AVX-512 instructions are processing arithmetic or math operations on double precision FP elements in vector mode (eight at a time).

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

The binary loop is composed of 164 FP arithmetical operations:

96: addition or subtraction
68: multiply

The binary loop is loading 1320 bytes (165 double precision FP elements). The binary loop is storing 256 bytes (32 double precision FP elements).

Arithmetic intensity

Arithmetic intensity is 0.10 FP operations per loaded or stored byte.

Unroll opportunity

Loop is potentially data access bound.

Workaround

Unroll your loop if trip count is significantly higher than target unroll factor and if some data references are common to consecutive iterations. This can be done manually. Or by recompiling with -funroll-loops and/or -floop-unroll-and-jam. Or with the unroll (resp. unroll_and_jam) directive on top of the inner (resp. surrounding) loop. You can enforce an unroll factor: !GCC$ unroll N

General properties

nb instructions	42
nb uops	41
loop length	285
used x86 registers	15
used mmx registers	0
used xmm registers	7
used ymm registers	0
used zmm registers	6
nb stack references	1
ADD-SUB / MUL ratio	1.00

Front-end

ASSUMED MACRO FUSION FIT IN UOP CACHE

micro-operation queue	5.13 cycles
front end	5.13 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14	P15
uops	0.33	0.33	0.33	0.33	0.33	0.33	7.25	7.25	7.25	7.25	7.50	7.50	6.50	6.50	3.00	3.00
cycles	0.33	0.33	0.33	0.33	0.33	0.33	7.25	7.25	7.25	7.25	7.50	7.50	6.50	6.50	3.00	3.00

Execution ports to units layout:

P0: ALU
P1: ALU
P2: ALU
P3: ALU, BRU
P4: ALU, BRU
P5: ALU, BRU
P6 (512 bits): store address, load
P7 (512 bits): store address, load
P8 (512 bits): store address, load
P9 (512 bits): store address, load
P10 (512 bits): VPU, DIV/SQRT
P11 (512 bits): VPU, DIV/SQRT
P12 (512 bits): VPU
P13 (512 bits): VPU
P14 (512 bits): FP store data
P15 (512 bits): FP store data

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

Cycles summary

Front-end	5.13
Dispatch	7.50
Data deps.	1.00
Overall L1	7.50

Vectorization ratios

INT

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

all	77%
load	83%
store	100%
mul	66%
add-sub	100%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	0%

INT+FP

all	73%
load	83%
store	100%
mul	66%
add-sub	100%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	0%

Vector efficiency ratios

INT

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

all	80%
load	85%
store	100%
mul	70%
add-sub	100%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	12%

INT+FP

all	76%
load	85%
store	100%
mul	70%
add-sub	100%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	12%

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 7.50 cycles. At this rate:

68% of peak load performance is reached (176.00 out of 256.00 bytes loaded per cycle (GB/s @ 1GHz))
26% of peak store performance is reached (34.13 out of 128.00 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: 42dfda

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14	P15	Latency	Recip. throughput	Vectorization
VMOVUPD (%RSI,%R10,1),%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.50	vect (100.0%)
VADDPD (%RDI,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULSD (%R9),%XMM2,%XMM25	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	scal (12.5%)
VBROADCASTSD %XMM25,%ZMM29	1	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	1	0.50	scal (12.5%)
VADDPD (%R14,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULPD (%R8,%R10,1),%ZMM29,%ZMM30	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVQ %XMM28,%R11	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	1	0.50	scal (12.5%)
VADDPD (%R13,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMOVQ %XMM7,%RDX	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	1	0.50	scal (12.5%)
VMULPD %ZMM30,%ZMM0,%ZMM0	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVUPD %ZMM0,(%RCX,%R10,1)	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0.50	0.50	4	1	vect (100.0%)
VMOVUPD (%R12,%R10,1),%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.50	vect (100.0%)
VADDPD (%RBX,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULSD (%R9),%XMM2,%XMM23	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	scal (12.5%)
VADDPD (%R11,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VBROADCASTSD %XMM23,%ZMM24	1	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	1	0.50	scal (12.5%)
VMULPD (%R15,%R10,1),%ZMM24,%ZMM25	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VADDPD (%RDX,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULPD %ZMM25,%ZMM0,%ZMM0	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVUPD %ZMM0,(%RAX,%R10,1)	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0.50	0.50	4	1	vect (100.0%)
VMOVUPD 0x40(%RSI,%R10,1),%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.50	vect (100.0%)
VADDPD 0x40(%RDI,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULSD (%R9),%XMM2,%XMM29	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	scal (12.5%)
VADDPD 0x40(%R14,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VBROADCASTSD %XMM29,%ZMM30	1	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	1	0.50	scal (12.5%)
VMULPD 0x40(%R8,%R10,1),%ZMM30,%ZMM23	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VADDPD 0x40(%R13,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULPD %ZMM23,%ZMM0,%ZMM0	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVUPD %ZMM0,0x40(%RCX,%R10,1)	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0.50	0.50	4	1	vect (100.0%)
VMOVUPD 0x40(%R12,%R10,1),%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.50	vect (100.0%)
VADDPD 0x40(%RBX,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULSD (%R9),%XMM2,%XMM24	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	scal (12.5%)
VADDPD 0x40(%R11,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VBROADCASTSD %XMM24,%ZMM25	1	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	1	0.50	scal (12.5%)
VMULPD 0x40(%R10,%R15,1),%ZMM25,%ZMM29	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
MOV 0x170(%RSP),%R11	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.25	N/A
VADDPD 0x40(%RDX,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULPD %ZMM29,%ZMM0,%ZMM0	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVUPD %ZMM0,0x40(%RAX,%R10,1)	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0.50	0.50	4	1	vect (100.0%)
SUB $-0x80,%R10	1	0.17	0.17	0.17	0.17	0.17	0.17	0	0	0	0	0	0	0	0	0	0	1	0.17	N/A
CMP %R11,%R10	1	0.17	0.17	0.17	0.17	0.17	0.17	0	0	0	0	0	0	0	0	0	0	1	0.17	N/A
JNE 42dfda <__flux_calc_kernel_module_MOD_flux_calc_kernel._omp_fn.0+0x64a>	1	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A

Function	__flux_calc_kernel_module_MOD_flux_calc_kernel._omp_fn.0
Source file and lines	flux_calc_kernel.f90:58-60
Module	exec

gain
potential
hint
expert

Vectorization

Details

73% of SSE/AVX instructions are used in vector version (process two or more data elements in vector registers):

83% of SSE/AVX loads are used in vector version.
66% of SSE/AVX multiply instructions are used in vector version.
0% of SSE/AVX instructions that are not load, store, addition, subtraction nor multiply instructions 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:
- recompile with fassociative-math (included in Ofast or ffast-math) to extend loop vectorization to FP reductions.
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: Fortran storage order is column-major: do i do j a(i,j) = b(i,j) (slow, non stride 1) => do i do j a(j,i) = b(i,j) (fast, stride 1)
- If your loop streams arrays of structures (AoS), try to use structures of arrays instead (SoA): do i a(i)%x = b(i)%x (slow, non stride 1) => do i a%x(i) = b%x(i) (fast, stride 1)

Execution units bottlenecks

Performance is limited by execution of FP multiply or FMA (fused multiply-add) operations (the FP multiply/FMA unit is a bottleneck).

Workaround

Reduce the number of FP multiply/FMA instructions

FMA

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: 2 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)

Vector unaligned load/store instructions

Detected 8 optimal vector unaligned load/store instructions.

Details

VMOVUPD: 8 occurrences►
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:58
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:58
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:60
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:60
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:58
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:58
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:60
- /home/eoseret/qaas_runs_ZEN5/174-049-0948/intel/CloverLeaf1.3-FC/build/CloverLeaf1.3-FC/CloverLeaf_ref/kernels/flux_calc_kernel.f90:60

Workaround

Use vector aligned instructions:

The GNU Fortran compiler does not support allocation alignment and does not feature directives to benefit from aligned data.
Use another compiler or locally use C code (for instance via libraries)

Type of elements and instruction set

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

The binary loop is composed of 164 FP arithmetical operations:

96: addition or subtraction
68: multiply

The binary loop is loading 1320 bytes (165 double precision FP elements). The binary loop is storing 256 bytes (32 double precision FP elements).

Arithmetic intensity

Arithmetic intensity is 0.10 FP operations per loaded or stored byte.

Unroll opportunity

Loop is potentially data access bound.

Workaround

General properties

nb instructions	42
nb uops	41
loop length	285
used x86 registers	15
used mmx registers	0
used xmm registers	7
used ymm registers	0
used zmm registers	6
nb stack references	1
ADD-SUB / MUL ratio	1.00

Front-end

ASSUMED MACRO FUSION FIT IN UOP CACHE

micro-operation queue	5.13 cycles
front end	5.13 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14	P15
uops	0.33	0.33	0.33	0.33	0.33	0.33	7.25	7.25	7.25	7.25	7.50	7.50	6.50	6.50	3.00	3.00
cycles	0.33	0.33	0.33	0.33	0.33	0.33	7.25	7.25	7.25	7.25	7.50	7.50	6.50	6.50	3.00	3.00

Execution ports to units layout:

P0: ALU
P1: ALU
P2: ALU
P3: ALU, BRU
P4: ALU, BRU
P5: ALU, BRU
P6 (512 bits): store address, load
P7 (512 bits): store address, load
P8 (512 bits): store address, load
P9 (512 bits): store address, load
P10 (512 bits): VPU, DIV/SQRT
P11 (512 bits): VPU, DIV/SQRT
P12 (512 bits): VPU
P13 (512 bits): VPU
P14 (512 bits): FP store data
P15 (512 bits): FP store data

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

Cycles summary

Front-end	5.13
Dispatch	7.50
Data deps.	1.00
Overall L1	7.50

Vectorization ratios

INT

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

all	77%
load	83%
store	100%
mul	66%
add-sub	100%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	0%

INT+FP

all	73%
load	83%
store	100%
mul	66%
add-sub	100%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	0%

Vector efficiency ratios

INT

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

all	80%
load	85%
store	100%
mul	70%
add-sub	100%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	12%

INT+FP

all	76%
load	85%
store	100%
mul	70%
add-sub	100%
fma	NA (no fma vectorizable/vectorized instructions)
div/sqrt	NA (no div/sqrt vectorizable/vectorized instructions)
other	12%

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 7.50 cycles. At this rate:

68% of peak load performance is reached (176.00 out of 256.00 bytes loaded per cycle (GB/s @ 1GHz))
26% of peak store performance is reached (34.13 out of 128.00 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: 42dfda

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	P12	P13	P14	P15	Latency	Recip. throughput	Vectorization
VMOVUPD (%RSI,%R10,1),%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.50	vect (100.0%)
VADDPD (%RDI,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULSD (%R9),%XMM2,%XMM25	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	scal (12.5%)
VBROADCASTSD %XMM25,%ZMM29	1	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	1	0.50	scal (12.5%)
VADDPD (%R14,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULPD (%R8,%R10,1),%ZMM29,%ZMM30	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVQ %XMM28,%R11	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	1	0.50	scal (12.5%)
VADDPD (%R13,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMOVQ %XMM7,%RDX	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	1	0.50	scal (12.5%)
VMULPD %ZMM30,%ZMM0,%ZMM0	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVUPD %ZMM0,(%RCX,%R10,1)	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0.50	0.50	4	1	vect (100.0%)
VMOVUPD (%R12,%R10,1),%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.50	vect (100.0%)
VADDPD (%RBX,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULSD (%R9),%XMM2,%XMM23	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	scal (12.5%)
VADDPD (%R11,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VBROADCASTSD %XMM23,%ZMM24	1	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	1	0.50	scal (12.5%)
VMULPD (%R15,%R10,1),%ZMM24,%ZMM25	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VADDPD (%RDX,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULPD %ZMM25,%ZMM0,%ZMM0	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVUPD %ZMM0,(%RAX,%R10,1)	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0.50	0.50	4	1	vect (100.0%)
VMOVUPD 0x40(%RSI,%R10,1),%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.50	vect (100.0%)
VADDPD 0x40(%RDI,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULSD (%R9),%XMM2,%XMM29	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	scal (12.5%)
VADDPD 0x40(%R14,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VBROADCASTSD %XMM29,%ZMM30	1	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	1	0.50	scal (12.5%)
VMULPD 0x40(%R8,%R10,1),%ZMM30,%ZMM23	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VADDPD 0x40(%R13,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULPD %ZMM23,%ZMM0,%ZMM0	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVUPD %ZMM0,0x40(%RCX,%R10,1)	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0.50	0.50	4	1	vect (100.0%)
VMOVUPD 0x40(%R12,%R10,1),%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.50	vect (100.0%)
VADDPD 0x40(%RBX,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULSD (%R9),%XMM2,%XMM24	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	scal (12.5%)
VADDPD 0x40(%R11,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VBROADCASTSD %XMM24,%ZMM25	1	0	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	1	0.50	scal (12.5%)
VMULPD 0x40(%R10,%R15,1),%ZMM25,%ZMM29	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
MOV 0x170(%RSP),%R11	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0	0	3	0.25	N/A
VADDPD 0x40(%RDX,%R10,1),%ZMM0,%ZMM0	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0.50	0.50	0	0	2	0.50	vect (100.0%)
VMULPD %ZMM29,%ZMM0,%ZMM0	1	0	0	0	0	0	0	0	0	0	0	0.50	0.50	0	0	0	0	3	0.50	vect (100.0%)
VMOVUPD %ZMM0,0x40(%RAX,%R10,1)	1	0	0	0	0	0	0	0.25	0.25	0.25	0.25	0	0	0	0	0.50	0.50	4	1	vect (100.0%)
SUB $-0x80,%R10	1	0.17	0.17	0.17	0.17	0.17	0.17	0	0	0	0	0	0	0	0	0	0	1	0.17	N/A
CMP %R11,%R10	1	0.17	0.17	0.17	0.17	0.17	0.17	0	0	0	0	0	0	0	0	0	0	1	0.17	N/A
JNE 42dfda <__flux_calc_kernel_module_MOD_flux_calc_kernel._omp_fn.0+0x64a>	1	0	0	0	0.33	0.33	0.33	0	0	0	0	0	0	0	0	0	0	1	0.50-1	N/A

Report Configuration

Vectorization

Details

Workaround

Execution units bottlenecks

Workaround

FMA

Workaround

Slow data structures access

Details

Workaround

Vector unaligned load/store instructions

Details

Workaround

Type of elements and instruction set

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

Arithmetic intensity

Unroll opportunity

Workaround

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

Execution units bottlenecks

Workaround

FMA

Workaround

Slow data structures access

Details

Workaround

Vector unaligned load/store instructions

Details

Workaround

Type of elements and instruction set

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

Arithmetic intensity

Unroll opportunity

Workaround

General properties

Front-end

Back-end

Cycles summary

Vectorization ratios

Vector efficiency ratios

Cycles and memory resources usage

Front-end bottlenecks

ASM code