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bench_pop_doc - 2025-12-19 17:32:40 - MAQAO 2025.1.4

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▼Stylizer  

[ 4 / 4 ] Application profile is long enough (45.53 s)

To have good quality measurements, it is advised that the application profiling time is greater than 10 seconds.

[ 3 / 3 ] Optimization level option is correctly used

[ 3 / 3 ] Most of time spent in analyzed modules comes from functions compiled with -g and -fno-omit-frame-pointer

-g option gives access to debugging informations, such are source locations. -fno-omit-frame-pointer improve the accuracy of callchains found during the application profiling.

[ 3 / 3 ] Host configuration allows retrieval of all necessary metrics.

[ 0 / 3 ] Compilation of some functions is not optimized for the target processor

Application run on the SKYLAKE micro-architecture while the code was specialized for skylake-avx512.

[ 2 / 2 ] Application is correctly profiled ("Others" category represents 0.07 % of the execution time)

To have a representative profiling, it is advised that the category "Others" represents less than 20% of the execution time in order to analyze as much as possible of the user code

[ 1 / 1 ] Lstopo present. The Topology lstopo report will be generated.

[ 0 / 0 ] Fastmath not used

Consider to add ffast-math to compilation flags (or replace -O3 with -Ofast) to unlock potential extra speedup by relaxing floating-point computation consistency. Warning: floating-point accuracy may be reduced and the compliance to IEEE/ISO rules/specifications for math functions will be relaxed, typically 'errno' will no longer be set after calling some math functions.

▼Strategizer  

[ 4 / 4 ] Enough time of the experiment time spent in analyzed loops (99.45%)

If the time spent in analyzed loops is less than 30%, standard loop optimizations will have a limited impact on application performances.

[ 4 / 4 ] Threads activity is good

On average, more than 99.89% of observed threads are actually active

[ 4 / 4 ] CPU activity is good

CPU cores are active 99.89% of time

[ 4 / 4 ] Loop profile is not flat

At least one loop coverage is greater than 4% (97.38%), representing an hotspot for the application

[ 4 / 4 ] Enough time of the experiment time spent in analyzed innermost loops (97.69%)

If the time spent in analyzed innermost loops is less than 15%, standard innermost loop optimizations such as vectorisation will have a limited impact on application performances.

[ 1 / 4 ] Affinity stability is lower than 90% (38.36%)

Threads are often migrating to other CPU cores/threads. For OpenMP, typically set (OMP_PLACES=cores OMP_PROC_BIND=close) or (OMP_PLACES=threads OMP_PROC_BIND=spread). With OpenMPI + OpenMP, use --bind-to core --map-by node:PE=$OMP_NUM_THREADS --report-bindings. With IntelMPI + OpenMP, set I_MPI_PIN_DOMAIN=omp:compact or I_MPI_PIN_DOMAIN=omp:scatter and use -print-rank-map.

[ 3 / 3 ] Less than 10% (0.00%) is spend in BLAS1 operations

It could be more efficient to inline by hand BLAS1 operations

[ 3 / 3 ] Functions mostly use all threads

Functions running on a reduced number of threads (typically sequential code) cover less than 10% of application walltime (0.00%)

[ 3 / 3 ] Cumulative Outermost/In between loops coverage (1.76%) lower than cumulative innermost loop coverage (97.69%)

Having cumulative Outermost/In between loops coverage greater than cumulative innermost loop coverage will make loop optimization more complex

[ 2 / 2 ] Less than 10% (0.00%) is spend in BLAS2 operations

BLAS2 calls usually could make a poor cache usage and could benefit from inlining.

[ 2 / 2 ] Less than 10% (0.27%) is spend in Libm/SVML (special functions)

▼Optimizer

Loop IDAnalysisPenalty Score
►Loop 508 - libqmckl.so.0.0.0+Execution Time: 97 % - Vectorization Ratio: 44.44 % - Vector Length Use: 26.39 %
►Loop Computation Issues+4
○[SA] Less than 10% of the FP ADD/SUB/MUL arithmetic operations are performed using FMA - Reorganize arithmetic expressions to exhibit potential for FMA. This issue costs 4 points.4
►Data Access Issues+12
○[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, BLEND/MERGE, Other_packing) - Simplify data access and try to get stride 1 access. There are 12 issues (= instructions) costing 1 point each.12
►Inefficient Vectorization+12
○[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, BLEND/MERGE, Other_packing) - Simplify data access and try to get stride 1 access. There are 12 issues (= instructions) costing 1 point each.12
►Loop 507 - libqmckl.so.0.0.0+Execution Time: 1 % - Vectorization Ratio: 30.77 % - Vector Length Use: 16.35 %
►Loop Computation Issues+2
○[SA] Presence of a large number of scalar integer instructions - Simplify loop structure, perform loop splitting or perform unroll and jam. This issue costs 2 points.2
►Control Flow Issues+37
○[SA] Too many paths (31 paths) - Simplify control structure. There are 31 issues ( = paths) costing 1 point each with a malus of 4 points.35
○[SA] Non innermost loop (InBetween) - Collapse loop with innermost ones. This issue costs 2 points.2
►Data Access Issues+6
○[SA] Presence of special instructions executing on a single port (BLEND/MERGE) - Simplify data access and try to get stride 1 access. There are 4 issues (= instructions) costing 1 point each.4
○[SA] More than 20% of the loads are accessing the stack - Perform loop splitting to decrease pressure on registers. This issue costs 2 points.2
►Vectorization Roadblocks+37
○[SA] Too many paths (31 paths) - Simplify control structure. There are 31 issues ( = paths) costing 1 point each with a malus of 4 points.35
○[SA] Non innermost loop (InBetween) - Collapse loop with innermost ones. This issue costs 2 points.2
►Inefficient Vectorization+4
○[SA] Presence of special instructions executing on a single port (BLEND/MERGE) - Simplify data access and try to get stride 1 access. There are 4 issues (= instructions) costing 1 point each.4
○Loop 619 - libqmckl.so.0.0.0Execution Time: 0 % - Vectorization Ratio: 100.00 % - Vector Length Use: 50.00 %
►Loop 505 - libqmckl.so.0.0.0+Execution Time: 0 % - Vectorization Ratio: 0.00 % - Vector Length Use: 12.50 %
►Control Flow Issues+37
○[SA] Too many paths (31 paths) - Simplify control structure. There are 31 issues ( = paths) costing 1 point each with a malus of 4 points.35
○[SA] Non innermost loop (InBetween) - Collapse loop with innermost ones. This issue costs 2 points.2
►Data Access Issues+2
○[SA] More than 20% of the loads are accessing the stack - Perform loop splitting to decrease pressure on registers. This issue costs 2 points.2
►Vectorization Roadblocks+37
○[SA] Too many paths (31 paths) - Simplify control structure. There are 31 issues ( = paths) costing 1 point each with a malus of 4 points.35
○[SA] Non innermost loop (InBetween) - Collapse loop with innermost ones. This issue costs 2 points.2
►Loop 618 - libqmckl.so.0.0.0+Execution Time: 0 % - Vectorization Ratio: 100.00 % - Vector Length Use: 50.00 %
►Loop Computation Issues+32
○[SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 8 issues (= instructions) costing 4 points each.32
►Data Access Issues+2
○[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 1 issues ( = data accesses) costing 2 point each.2
►Vectorization Roadblocks+2
○[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 1 issues ( = data accesses) costing 2 point each.2
►Loop 615 - libqmckl.so.0.0.0+Execution Time: 0 % - Vectorization Ratio: 100.00 % - Vector Length Use: 50.00 %
►Loop Computation Issues+32
○[SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 8 issues (= instructions) costing 4 points each.32
►Data Access Issues+2
○[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 1 issues ( = data accesses) costing 2 point each.2
►Vectorization Roadblocks+2
○[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 1 issues ( = data accesses) costing 2 point each.2
►Loop 504 - libqmckl.so.0.0.0+Execution Time: 0 % - Vectorization Ratio: 50.00 % - Vector Length Use: 28.13 %
►Loop Computation Issues+6
○[SA] Less than 10% of the FP ADD/SUB/MUL arithmetic operations are performed using FMA - Reorganize arithmetic expressions to exhibit potential for FMA. This issue costs 4 points.4
○[SA] Presence of a large number of scalar integer instructions - Simplify loop structure, perform loop splitting or perform unroll and jam. This issue costs 2 points.2
►Control Flow Issues+1
○[SA] Presence of calls - Inline either by compiler or by hand and use SVML for libm calls. There are 1 issues (= calls) costing 1 point each.1
►Data Access Issues+10
○[SA] Presence of indirect accesses - Use array restructuring or gather instructions to lower the cost. There are 1 issues ( = indirect data accesses) costing 4 point each.4
○[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT) - Simplify data access and try to get stride 1 access. There are 6 issues (= instructions) costing 1 point each.6
►Vectorization Roadblocks+5
○[SA] Presence of calls - Inline either by compiler or by hand and use SVML for libm calls. There are 1 issues (= calls) costing 1 point each.1
○[SA] Presence of indirect accesses - Use array restructuring or gather instructions to lower the cost. There are 1 issues ( = indirect data accesses) costing 4 point each.4
►Inefficient Vectorization+6
○[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT) - Simplify data access and try to get stride 1 access. There are 6 issues (= instructions) costing 1 point each.6
►Loop 767 - libqmckl.so.0.0.0+Execution Time: 0 % - Vectorization Ratio: 100.00 % - Vector Length Use: 50.00 %
►Loop Computation Issues+4
○[SA] Less than 10% of the FP ADD/SUB/MUL arithmetic operations are performed using FMA - Reorganize arithmetic expressions to exhibit potential for FMA. This issue costs 4 points.4
►Loop 195 - libqmckl.so.0.0.0+Execution Time: 0 % - Vectorization Ratio: 100.00 % - Vector Length Use: 50.00 %
►Data Access Issues+4
○[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 2 issues ( = data accesses) costing 2 point each.4
►Vectorization Roadblocks+4
○[SA] Presence of constant non unit stride data access - Use array restructuring, perform loop interchange or use gather instructions to lower a bit the cost. There are 2 issues ( = data accesses) costing 2 point each.4
►Loop 343 - libqmckl.so.0.0.0+Execution Time: 0 % - Vectorization Ratio: 50.00 % - Vector Length Use: 26.95 %
►Loop Computation Issues+5
○[SA] Peel/tail loop, considered having a low iteration count - Perform full unroll. Force compiler to use masked instructions. This issue costs 5 points.5
►Control Flow Issues+5
○[SA] Peel/tail loop, considered having a low iteration count - Perform full unroll. Force compiler to use masked instructions. This issue costs 5 points.5
►Data Access Issues+28
○[SA] Presence of indirect accesses - Use array restructuring or gather instructions to lower the cost. There are 1 issues ( = indirect data accesses) costing 4 point each.4
○[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, Other_packing) - Simplify data access and try to get stride 1 access. There are 24 issues (= instructions) costing 1 point each.24
►Vectorization Roadblocks+4
○[SA] Presence of indirect accesses - Use array restructuring or gather instructions to lower the cost. There are 1 issues ( = indirect data accesses) costing 4 point each.4
►Inefficient Vectorization+24
○[SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, Other_packing) - Simplify data access and try to get stride 1 access. There are 24 issues (= instructions) costing 1 point each.24
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