Merge branch 'master' of github.com:RRZE-HPC/TheBandwidthBenchmark

README.md

@@ -102,3 +102,16 @@ SDaxpy:        46822.63    23411.32      0.0281       0.0273       0.0325
 ----------------------------------------------------------------------------
 Solution Validates
 ```
+
+A perl wrapper script (bench.pl) is also provided to scan ranges of thread counts and determine the absolute highest sustained main memory bandwidth. In order to use it `likwid-pin` has to be in your path. The script has three required and one optional command line arguments:
+```
+$./bench.pl <executable> <thread count range>  <repititions> [<SMT setting>] 
+```
+Example usage:
+```
+$./bench.pl ./bwbench-GCC 2-8 6
+```
+The script will always use physical cores only, where two SMT threads is the default. For different SMT thread counts use the 4th command line argument. Example for a processor without SMT:
+```
+$./bench.pl ./bwbench-GCC 14-24  10  1
+```

bench.pl

@@ -0,0 +1,23 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use utf8;
+
+my $CMD = $ARGV[0];
+my @N =  split /-/, $ARGV[1];
+my $R = $ARGV[2];
+my $MAX = 0; my $CORES = 0; my $BENCH = '';
+my $SMT = $ARGV[3] ? $ARGV[3] : 2;
+
+foreach my $numcores ( $N[0] ... $N[1] ) {
+    foreach ( 1 ... $R ) {
+        foreach my $ln ( split /\n/, `likwid-pin -c E:S0:$numcores:1:$SMT $CMD` ){
+            if ( $ln =~ /^([A-Za-z]+):[ ]+([0-9.]+) /) {
+                if ( $MAX < $2 ){
+                    $MAX = $2; $CORES = $numcores; $BENCH = $1;
+                }
+            }
+        }
+    }
+}
+print "$BENCH was best using $CORES threads: $MAX\n";