OV - exec - Loop 1020

	Loop Id: 1020	Module: exec	Source: MultiBsplineRef.hpp:276-286	Coverage: 0.50%

0x486f18 VMULSD	(%R9,%R10,1),%XMM10,%XMM0    [1]

0x486f1e VMULSD	(%R11,%R10,1),%XMM7,%XMM8    [2]

0x486f24 VMOVSD	%XMM0,(%R9,%R10,1)    [1]

0x486f2a VMULSD	(%R14,%R10,1),%XMM11,%XMM1    [5]

0x486f30 VMOVSD	%XMM8,(%R11,%R10,1)    [2]

0x486f36 VMULSD	(%R15,%R10,1),%XMM6,%XMM3    [6]

0x486f3c VMOVSD	%XMM1,(%R14,%R10,1)    [5]

0x486f42 VMULSD	(%RDX,%R10,1),%XMM12,%XMM9    [9]

0x486f48 VMOVSD	%XMM3,(%R15,%R10,1)    [6]

0x486f4e VMULSD	(%RCX,%R10,1),%XMM5,%XMM4    [8]

0x486f54 VMOVSD	%XMM9,(%RDX,%R10,1)    [9]

0x486f5a VMULSD	(%R13,%R10,1),%XMM2,%XMM15    [4]

0x486f61 VMOVSD	%XMM4,(%RCX,%R10,1)    [8]

0x486f67 VMULSD	0x8(%R11,%R10,1),%XMM7,%XMM4    [2]

0x486f6e VMOVSD	%XMM15,(%R13,%R10,1)    [4]

0x486f75 VMULSD	(%R12,%R10,1),%XMM13,%XMM8    [3]

0x486f7b VMOVSD	%XMM4,0x8(%R11,%R10,1)    [2]

0x486f82 VMULSD	0x8(%R15,%R10,1),%XMM6,%XMM0    [6]

0x486f89 VMOVSD	%XMM8,(%R12,%R10,1)    [3]

0x486f8f VMULSD	(%RAX,%R10,1),%XMM14,%XMM3    [7]

0x486f95 VMOVSD	%XMM0,0x8(%R15,%R10,1)    [6]

0x486f9c VMULSD	0x8(%RCX,%R10,1),%XMM5,%XMM1    [8]

0x486fa3 VMOVSD	%XMM3,(%RAX,%R10,1)    [7]

0x486fa9 VMULSD	0x8(%R9,%R10,1),%XMM10,%XMM9    [1]

0x486fb0 VMOVSD	%XMM1,0x8(%RCX,%R10,1)    [8]

0x486fb7 VMOVSD	%XMM9,0x8(%R9,%R10,1)    [1]

0x486fbe VMULSD	0x8(%R14,%R10,1),%XMM11,%XMM15    [5]

0x486fc5 VMOVSD	%XMM15,0x8(%R14,%R10,1)    [5]

0x486fcc VMULSD	0x8(%RDX,%R10,1),%XMM12,%XMM8    [9]

0x486fd3 VMOVSD	%XMM8,0x8(%RDX,%R10,1)    [9]

0x486fda VMULSD	0x8(%R13,%R10,1),%XMM2,%XMM3    [4]

0x486fe1 VMOVSD	%XMM3,0x8(%R13,%R10,1)    [4]

0x486fe8 VMULSD	0x8(%R12,%R10,1),%XMM13,%XMM4    [3]

0x486fef VMOVSD	%XMM4,0x8(%R12,%R10,1)    [3]

0x486ff6 VMULSD	0x8(%RAX,%R10,1),%XMM14,%XMM0    [7]

0x486ffd VMOVSD	%XMM0,0x8(%RAX,%R10,1)    [7]

0x487004 ADD	$0x10,%R10

0x487008 CMP	%R10,%R8

0x48700b JNE	486f18

/home/eoseret/qaas_runs_GNR/173-773-5521/intel/miniqmc/build/miniqmc/src/Numerics/Spline2/MultiBsplineRef.hpp: 276 - 286

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

276:   for (int n = 0; n < num_splines; n++)

277:   {

278:     gx[n] *= dxInv;

279:     gy[n] *= dyInv;

280:     gz[n] *= dzInv;

281:     hxx[n] *= dxx;

282:     hyy[n] *= dyy;

283:     hzz[n] *= dzz;

284:     hxy[n] *= dxy;

285:     hxz[n] *= dxz;

286:     hyz[n] *= dyz;

Coverage (%)	Name	Source Location	Module
►80.44+	miniqmcreference::einspline_sp[...]	einspline_spo_ref.hpp:206	exec
○	miniqmcreference::DiracDetermi[...]	DiracDeterminantRef.cpp:100	exec
○	qmcplusplus::WaveFunction::rat[...]	WaveFunction.cpp:198	exec
○	main._omp_fn.1	refwrap.h:350	exec
○	gomp_thread_start	team.c:130	libgomp.so.1.0.0
►8.87+	miniqmcreference::einspline_sp[...]	einspline_spo_ref.hpp:206	exec
○	miniqmcreference::DiracDetermi[...]	OhmmsVector.h:144	exec
○	qmcplusplus::WaveFunction::eva[...]	WaveFunction.cpp:171	exec
○	main._omp_fn.0	miniqmc.cpp:397	exec
○	gomp_thread_start	team.c:130	libgomp.so.1.0.0
►8.27+	miniqmcreference::einspline_sp[...]	einspline_spo_ref.hpp:206	exec
○	miniqmcreference::DiracDetermi[...]	OhmmsVector.h:144	exec
○	qmcplusplus::WaveFunction::eva[...]	WaveFunction.cpp:171	exec
○	main._omp_fn.0	miniqmc.cpp:397	exec
○	gomp_thread_start	team.c:130	libgomp.so.1.0.0
►2.02+	miniqmcreference::einspline_sp[...]	einspline_spo_ref.hpp:206	exec
○	miniqmcreference::DiracDetermi[...]	DiracDeterminantRef.cpp:100	exec
○	qmcplusplus::WaveFunction::rat[...]	WaveFunction.cpp:198	exec
○	main._omp_fn.1	refwrap.h:350	exec
○	GOMP_parallel	libgomp.h:982	libgomp.so.1.0.0

Path /

Metric	Value
CQA speedup if no scalar integer	1.00
CQA speedup if FP arith vectorized	1.04
CQA speedup if fully vectorized	8.00
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.04
Bottlenecks	micro-operation queue,
Function	void miniqmcreference::MultiBsplineEvalRef::evaluate_vgh(qmcplusplus::bspline_traits::SplineType const, double, double, double, double, double, double, unsigned long)
Source	MultiBsplineRef.hpp:276-286
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	9.33
CQA cycles if no scalar integer	9.33
CQA cycles if FP arith vectorized	9.00
CQA cycles if fully vectorized	1.17
Front-end cycles	9.33
P0 cycles	9.00
P1 cycles	9.00
P2 cycles	6.00
P3 cycles	6.00
P4 cycles	9.00
P5 cycles	0.00
P6 cycles	1.00
P7 cycles	9.00
P8 cycles	9.00
P9 cycles	9.00
P10 cycles	0.00
P11 cycles	6.00
DIV/SQRT cycles	0.00
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	39.00
Nb uops	38.00
Nb loads	18.00
Nb stores	18.00
Nb stack references	0.00
FLOP/cycle	1.93
Nb FLOP add-sub	0.00
Nb FLOP mul	18.00
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	30.86
Bytes prefetched	0.00
Bytes loaded	144.00
Bytes stored	144.00
Stride 0	0.00
Stride 1	9.00
Stride n	0.00
Stride unknown	0.00
Stride indirect	0.00
Vectorization ratio all	0.00
Vectorization ratio load	0.00
Vectorization ratio store	0.00
Vectorization ratio mul	0.00
Vectorization ratio add_sub	NA
Vectorization ratio fma	NA
Vectorization ratio div_sqrt	NA
Vectorization ratio other	NA
Vector-efficiency ratio all	12.50
Vector-efficiency ratio load	12.50
Vector-efficiency ratio store	12.50
Vector-efficiency ratio mul	12.50
Vector-efficiency ratio add_sub	NA
Vector-efficiency ratio fma	NA
Vector-efficiency ratio div_sqrt	NA
Vector-efficiency ratio other	NA

Metric	Value
CQA speedup if no scalar integer	1.00
CQA speedup if FP arith vectorized	1.04
CQA speedup if fully vectorized	8.00
CQA speedup if no inter-iteration dependency	NA
CQA speedup if next bottleneck killed	1.04
Bottlenecks	micro-operation queue,
Function	void miniqmcreference::MultiBsplineEvalRef::evaluate_vgh(qmcplusplus::bspline_traits::SplineType const, double, double, double, double, double, double, unsigned long)
Source	MultiBsplineRef.hpp:276-286
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	9.33
CQA cycles if no scalar integer	9.33
CQA cycles if FP arith vectorized	9.00
CQA cycles if fully vectorized	1.17
Front-end cycles	9.33
P0 cycles	9.00
P1 cycles	9.00
P2 cycles	6.00
P3 cycles	6.00
P4 cycles	9.00
P5 cycles	0.00
P6 cycles	1.00
P7 cycles	9.00
P8 cycles	9.00
P9 cycles	9.00
P10 cycles	0.00
P11 cycles	6.00
DIV/SQRT cycles	0.00
Inter-iter dependencies cycles	1
FE+BE cycles (UFS)	NA
Stall cycles (UFS)	NA
Nb insns	39.00
Nb uops	38.00
Nb loads	18.00
Nb stores	18.00
Nb stack references	0.00
FLOP/cycle	1.93
Nb FLOP add-sub	0.00
Nb FLOP mul	18.00
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	30.86
Bytes prefetched	0.00
Bytes loaded	144.00
Bytes stored	144.00
Stride 0	0.00
Stride 1	9.00
Stride n	0.00
Stride unknown	0.00
Stride indirect	0.00
Vectorization ratio all	0.00
Vectorization ratio load	0.00
Vectorization ratio store	0.00
Vectorization ratio mul	0.00
Vectorization ratio add_sub	NA
Vectorization ratio fma	NA
Vectorization ratio div_sqrt	NA
Vectorization ratio other	NA
Vector-efficiency ratio all	12.50
Vector-efficiency ratio load	12.50
Vector-efficiency ratio store	12.50
Vector-efficiency ratio mul	12.50
Vector-efficiency ratio add_sub	NA
Vector-efficiency ratio fma	NA
Vector-efficiency ratio div_sqrt	NA
Vector-efficiency ratio other	NA

Path /

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

Function	void miniqmcreference::MultiBsplineEvalRef::evaluate_vgh(qmcplusplus::bspline_traits::SplineType const, double, double, double, double, double, double, unsigned long)
Source file and lines	MultiBsplineRef.hpp:276-286
Module	exec

The loop is defined in /home/eoseret/qaas_runs_GNR/173-773-5521/intel/miniqmc/build/miniqmc/src/Numerics/Spline2/MultiBsplineRef.hpp:276-286.

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

gain
potential
hint
expert

Vectorization

Your loop is not vectorized. 8 data elements could be processed at once in vector registers.

By vectorizing your loop, you can lower the cost of an iteration from 9.33 to 1.17 cycles (8.00x speedup).

Details

All SSE/AVX instructions are used in scalar version (process only one data element in vector registers). Since your execution units are vector units, only a vectorized loop can use their full power.

Workaround

Try another compiler or update/tune your current one
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: C storage order is row-major: for(i) for(j) a[j][i] = b[j][i]; (slow, non stride 1) => for(i) for(j) a[i][j] = b[i][j]; (fast, stride 1)
- If your loop streams arrays of structures (AoS), try to use structures of arrays instead (SoA): for(i) a[i].x = b[i].x; (slow, non stride 1) => for(i) a.x[i] = b.x[i]; (fast, stride 1)

Execution units bottlenecks

Found no such bottlenecks but see expert reports for more complex bottlenecks.

No data for this section

Type of elements and instruction set

18 SSE or AVX instructions are processing arithmetic or math operations on double precision FP elements in scalar mode (one at a time).

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

The binary loop is composed of 18 FP arithmetical operations:

18: multiply

The binary loop is loading 144 bytes (18 double precision FP elements). The binary loop is storing 144 bytes (18 double precision FP elements).

Arithmetic intensity

Arithmetic intensity is 0.06 FP operations per loaded or stored byte.

Unroll opportunity

Loop is 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: #pragma GCC unroll N

General properties

nb instructions	39
nb uops	38
loop length	249
used x86 registers	11
used mmx registers	0
used xmm registers	16
used ymm registers	0
used zmm registers	0
nb stack references	0

Front-end

ASSUMED MACRO FUSION FIT IN UOP CACHE

micro-operation queue	9.33 cycles
front end	9.33 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11
uops	9.00	9.00	6.00	6.00	9.00	0.00	1.00	9.00	9.00	9.00	0.00	6.00
cycles	9.00	9.00	6.00	6.00	9.00	0.00	1.00	9.00	9.00	9.00	0.00	6.00

Execution ports to units layout:

P0 (256 bits): VPU, BRU, ALU, DIV/SQRT
P1 (256 bits): ALU, VPU
P2 (512 bits): load
P3 (512 bits): load
P4 (512 bits): store data
P5 (512 bits): ALU, VPU
P6: ALU, BRU
P7: store address
P8: store address
P9 (512 bits): store data
P10: ALU
P11 (512 bits): load

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

Cycles summary

Front-end	9.33
Dispatch	9.00
Data deps.	1.00
Overall L1	9.33

Vectorization ratios

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

Vector efficiency ratios

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

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 9.33 cycles. At this rate:

8% of peak load performance is reached (15.43 out of 192.00 bytes loaded per cycle (GB/s @ 1GHz))
12% of peak store performance is reached (15.43 out of 128.00 bytes stored per cycle (GB/s @ 1GHz))

Front-end bottlenecks

Performance is limited by instruction throughput (loading/decoding program instructions to execution core) (front-end is a bottleneck).

ASM code

In the binary file, the address of the loop is: 486f18

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	Latency	Recip. throughput	Vectorization
VMULSD (%R9,%R10,1),%XMM10,%XMM0	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMULSD (%R11,%R10,1),%XMM7,%XMM8	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM0,(%R9,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%R14,%R10,1),%XMM11,%XMM1	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM8,(%R11,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%R15,%R10,1),%XMM6,%XMM3	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM1,(%R14,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%RDX,%R10,1),%XMM12,%XMM9	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM3,(%R15,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%RCX,%R10,1),%XMM5,%XMM4	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM9,(%RDX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%R13,%R10,1),%XMM2,%XMM15	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM4,(%RCX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R11,%R10,1),%XMM7,%XMM4	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM15,(%R13,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%R12,%R10,1),%XMM13,%XMM8	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM4,0x8(%R11,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R15,%R10,1),%XMM6,%XMM0	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM8,(%R12,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%RAX,%R10,1),%XMM14,%XMM3	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM0,0x8(%R15,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%RCX,%R10,1),%XMM5,%XMM1	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM3,(%RAX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R9,%R10,1),%XMM10,%XMM9	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM1,0x8(%RCX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMOVSD %XMM9,0x8(%R9,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R14,%R10,1),%XMM11,%XMM15	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM15,0x8(%R14,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%RDX,%R10,1),%XMM12,%XMM8	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM8,0x8(%RDX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R13,%R10,1),%XMM2,%XMM3	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM3,0x8(%R13,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R12,%R10,1),%XMM13,%XMM4	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM4,0x8(%R12,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%RAX,%R10,1),%XMM14,%XMM0	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM0,0x8(%RAX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
ADD $0x10,%R10	1	0	0	0	0	0	0	0	0	0	0	0	0	1	0.17	N/A
CMP %R10,%R8	1	0.20	0.20	0	0	0	0.20	0.20	0	0	0	0.20	0	1	0.20	N/A
JNE 486f18 <_ZN16miniqmcreference19MultiBsplineEvalRef12evaluate_vghIdEEvPKN11qmcplusplus14bspline_traitsIT_Lj3EE10SplineTypeES4_S4_S4_PS4_S9_S9_m+0x9d8>	1	0.50	0	0	0	0	0	0.50	0	0	0	0	0	0	0.50	N/A

Function	void miniqmcreference::MultiBsplineEvalRef::evaluate_vgh(qmcplusplus::bspline_traits::SplineType const, double, double, double, double, double, double, unsigned long)
Source file and lines	MultiBsplineRef.hpp:276-286
Module	exec

gain
potential
hint
expert

Vectorization

Your loop is not vectorized. 8 data elements could be processed at once in vector registers.

By vectorizing your loop, you can lower the cost of an iteration from 9.33 to 1.17 cycles (8.00x speedup).

Details

All SSE/AVX instructions are used in scalar version (process only one data element in vector registers). Since your execution units are vector units, only a vectorized loop can use their full power.

Workaround

Try another compiler or update/tune your current one
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: C storage order is row-major: for(i) for(j) a[j][i] = b[j][i]; (slow, non stride 1) => for(i) for(j) a[i][j] = b[i][j]; (fast, stride 1)
- If your loop streams arrays of structures (AoS), try to use structures of arrays instead (SoA): for(i) a[i].x = b[i].x; (slow, non stride 1) => for(i) a.x[i] = b.x[i]; (fast, stride 1)

Execution units bottlenecks

Found no such bottlenecks but see expert reports for more complex bottlenecks.

No data for this section

Type of elements and instruction set

18 SSE or AVX instructions are processing arithmetic or math operations on double precision FP elements in scalar mode (one at a time).

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

The binary loop is composed of 18 FP arithmetical operations:

18: multiply

The binary loop is loading 144 bytes (18 double precision FP elements). The binary loop is storing 144 bytes (18 double precision FP elements).

Arithmetic intensity

Arithmetic intensity is 0.06 FP operations per loaded or stored byte.

Unroll opportunity

Loop is data access bound.

Workaround

General properties

nb instructions	39
nb uops	38
loop length	249
used x86 registers	11
used mmx registers	0
used xmm registers	16
used ymm registers	0
used zmm registers	0
nb stack references	0

Front-end

ASSUMED MACRO FUSION FIT IN UOP CACHE

micro-operation queue	9.33 cycles
front end	9.33 cycles

Back-end

	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11
uops	9.00	9.00	6.00	6.00	9.00	0.00	1.00	9.00	9.00	9.00	0.00	6.00
cycles	9.00	9.00	6.00	6.00	9.00	0.00	1.00	9.00	9.00	9.00	0.00	6.00

Execution ports to units layout:

P0 (256 bits): VPU, BRU, ALU, DIV/SQRT
P1 (256 bits): ALU, VPU
P2 (512 bits): load
P3 (512 bits): load
P4 (512 bits): store data
P5 (512 bits): ALU, VPU
P6: ALU, BRU
P7: store address
P8: store address
P9 (512 bits): store data
P10: ALU
P11 (512 bits): load

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

Cycles summary

Front-end	9.33
Dispatch	9.00
Data deps.	1.00
Overall L1	9.33

Vectorization ratios

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

Vector efficiency ratios

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

Cycles and memory resources usage

Assuming all data fit into the L1 cache, each iteration of the binary loop takes 9.33 cycles. At this rate:

8% of peak load performance is reached (15.43 out of 192.00 bytes loaded per cycle (GB/s @ 1GHz))
12% of peak store performance is reached (15.43 out of 128.00 bytes stored per cycle (GB/s @ 1GHz))

Front-end bottlenecks

Performance is limited by instruction throughput (loading/decoding program instructions to execution core) (front-end is a bottleneck).

ASM code

In the binary file, the address of the loop is: 486f18

Instruction	Nb FU	P0	P1	P2	P3	P4	P5	P6	P7	P8	P9	P10	P11	Latency	Recip. throughput	Vectorization
VMULSD (%R9,%R10,1),%XMM10,%XMM0	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMULSD (%R11,%R10,1),%XMM7,%XMM8	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM0,(%R9,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%R14,%R10,1),%XMM11,%XMM1	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM8,(%R11,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%R15,%R10,1),%XMM6,%XMM3	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM1,(%R14,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%RDX,%R10,1),%XMM12,%XMM9	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM3,(%R15,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%RCX,%R10,1),%XMM5,%XMM4	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM9,(%RDX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%R13,%R10,1),%XMM2,%XMM15	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM4,(%RCX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R11,%R10,1),%XMM7,%XMM4	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM15,(%R13,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%R12,%R10,1),%XMM13,%XMM8	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM4,0x8(%R11,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R15,%R10,1),%XMM6,%XMM0	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM8,(%R12,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD (%RAX,%R10,1),%XMM14,%XMM3	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM0,0x8(%R15,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%RCX,%R10,1),%XMM5,%XMM1	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM3,(%RAX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R9,%R10,1),%XMM10,%XMM9	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM1,0x8(%RCX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMOVSD %XMM9,0x8(%R9,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R14,%R10,1),%XMM11,%XMM15	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM15,0x8(%R14,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%RDX,%R10,1),%XMM12,%XMM8	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM8,0x8(%RDX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R13,%R10,1),%XMM2,%XMM3	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM3,0x8(%R13,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%R12,%R10,1),%XMM13,%XMM4	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM4,0x8(%R12,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
VMULSD 0x8(%RAX,%R10,1),%XMM14,%XMM0	1	0.50	0.50	0.33	0.33	0	0	0	0	0	0	0	0.33	4	0.50	scal (12.5%)
VMOVSD %XMM0,0x8(%RAX,%R10,1)	1	0	0	0	0	0.50	0	0	0.50	0.50	0.50	0	0	1	0.50	scal (12.5%)
ADD $0x10,%R10	1	0	0	0	0	0	0	0	0	0	0	0	0	1	0.17	N/A
CMP %R10,%R8	1	0.20	0.20	0	0	0	0.20	0.20	0	0	0	0.20	0	1	0.20	N/A
JNE 486f18 <_ZN16miniqmcreference19MultiBsplineEvalRef12evaluate_vghIdEEvPKN11qmcplusplus14bspline_traitsIT_Lj3EE10SplineTypeES4_S4_S4_PS4_S9_S9_m+0x9d8>	1	0.50	0	0	0	0	0	0.50	0	0	0	0	0	0	0.50	N/A

Report Configuration

Vectorization

Details

Workaround

Execution units bottlenecks

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

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