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kmeans-gcc-O3-funroll - 2025-06-03 14:08:35 - MAQAO 2.21.4

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Stylizer  

[ 4 / 4 ] Application profile is long enough (29.98 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

[ 2.40 / 3 ] Most of time spent in analyzed modules comes from functions compiled with -g

-g option gives access to debugging informations, such are source locations. Add -fno-omit-frame-pointer to 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 cascadelake.

[ 2 / 2 ] Application is correctly profiled ("Others" category represents 0.00 % 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 (98.60%)

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

[ 0 / 4 ] CPU activity is below 90% (21.69%)

CPU cores are idle more than 10% of time. Threads supposed to run on these cores are probably IO/sync waiting. Some hints: use faster filesystems to read/write data, improve parallel load balancing and/or scheduling.

[ 0 / 4 ] A significant amount of threads are idle (78.31%)

On average, more than 10% of observed threads are idle. Such threads are probably IO/sync waiting. Some hints: use faster filesystems to read/write data, improve parallel load balancing and/or scheduling.

[ 0 / 4 ] Affinity stability is lower than 90% (18.36%)

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.

[ 4 / 4 ] Loop profile is not flat

At least one loop coverage is greater than 4% (89.75%), representing an hotspot for the application

[ 4 / 4 ] Enough time of the experiment time spent in analyzed innermost loops (93.25%)

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.

[ 3 / 3 ] Cumulative Outermost/In between loops coverage (5.35%) lower than cumulative innermost loop coverage (93.25%)

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

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

It could be more efficient to inline by hand BLAS1 operations

[ 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% (0.00%) is spend in Libm/SVML (special functions)

Optimizer

Loop IDAnalysisPenalty Score
Loop 1 - kmeans-gcc-O3-funroll+Execution Time: 89 % - Vectorization Ratio: 14.29 % - Vector Length Use: 13.39 %
Control Flow Issues+20
[SA] Too many paths (16 paths) - Simplify control structure. There are 16 issues ( = paths) costing 1 point each with a malus of 4 points.20
Vectorization Roadblocks+20
[SA] Too many paths (16 paths) - Simplify control structure. There are 16 issues ( = paths) costing 1 point each with a malus of 4 points.20
Loop 2 - kmeans-gcc-O3-funroll+Execution Time: 5 % - Vectorization Ratio: 12.12 % - Vector Length Use: 11.74 %
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+260
[SA] Too many paths (254 paths) - Simplify control structure. There are 254 issues ( = paths) costing 1 point each with a malus of 4 points.258
[SA] Non innermost loop (Outermost) - Collapse loop with innermost ones. This issue costs 2 points.2
Vectorization Roadblocks+260
[SA] Too many paths (254 paths) - Simplify control structure. There are 254 issues ( = paths) costing 1 point each with a malus of 4 points.258
[SA] Non innermost loop (Outermost) - Collapse loop with innermost ones. This issue costs 2 points.2
Loop 6 - kmeans-gcc-O3-funroll+Execution Time: 3 % - Vectorization Ratio: 0.00 % - Vector Length Use: 11.61 %
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
Data Access Issues+12
[SA] Presence of indirect accesses - Use array restructuring or gather instructions to lower the cost. There are 3 issues ( = indirect data accesses) costing 4 point each.12
Vectorization Roadblocks+12
[SA] Presence of indirect accesses - Use array restructuring or gather instructions to lower the cost. There are 3 issues ( = indirect data accesses) costing 4 point each.12
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