Poor man's sampling profiler for NuttX

Debug/poor-mans-profiler.sh

@@ -0,0 +1,66 @@
+#!/bin/bash
+#
+# Poor man's sampling profiler for NuttX.
+#
+# The stack folding script was inspired by stackcollapse-gdb.pl from the FlameGraph project.
+#
+# Usage: Install flamegraph.pl in your PATH, define the variables below, configure your .gdbinit, run the script and go
+#        have a coffee. When you're back, you'll see the flamegraph. Note that frequent calls to GDB significantly
+#        interfere with normal operation of the target, which means that you can't profile real-time tasks with it.
+#
+# Requirements: ARM GDB with Python support
+#
+
+root=$(dirname $0)/..
+
+nsamples=100
+sleeptime=0.01    # Doctors recommend 7-8 hours a day
+taskname=uavcan
+exe=$root/Build/px4fmu-v2_default.build/firmware.elf
+
+set -e
+
+stacksfile=/tmp/$taskname-stacks.log
+
+cd $root
+rm -f $stacksfile
+echo "Sampling..."
+
+for x in $(seq 1 $nsamples)
+do
+    arm-none-eabi-gdb $exe --batch -ex "set print asm-demangle on" \
+                                   -ex "source $root/Debug/Nuttx.py" \
+                                   -ex "show mybt $taskname" \
+        2> /dev/null \
+        | sed -n 's/0\.0:\(#.*\)/\1/p' \
+        >> $stacksfile
+    echo -e '\n\n' >> $stacksfile
+    echo -ne "\r$x/$nsamples"
+    sleep $sleeptime
+done
+
+echo
+echo "Stacks saved to $stacksfile"
+
+cat $stacksfile | perl -e 'my $current = "";
+my %stacks;
+while(<>) {
+  if(m/^#[0-9]*\s*0x[a-zA-Z0-9]*\s*in (.*) at/) {
+    if ($1 ne "None") {
+      if ($current eq "") { $current = $1; }
+      else { $current = $1 . ";" . $current; }
+    }
+  } elsif(!($current eq "")) {
+    $stacks{$current} += 1;
+    $current = "";
+  }
+}
+foreach my $k (sort { $a cmp $b } keys %stacks) {
+  print "$k $stacks{$k}\n";
+}' > /tmp/$taskname-folded.txt
+
+echo "Folded stacks saved to /tmp/$taskname-folded.txt"
+
+cat /tmp/$taskname-folded.txt | flamegraph.pl --fontsize=8 --width=1800 > /tmp/$taskname-flamegraph.svg
+
+xdg-open /tmp/$taskname-flamegraph.svg