====== perf on low-end hardware ======

If perf binary is not available:
  * copy the tools/ directory of the current running kernel tree
  * apt-get install flex bison libc-dev libc-dev libelf-dev libslang2-dev libunwind-dev binutils-dev libiberty-dev
  * make -C tools/perf/

If hardware performance counters are not available:
<code>
# ./linux/tools/perf/perf record -a factor 2365873330313
Error:
PMU Hardware doesn't support sampling/overflow-interrupts.
/o\
</code>

Then use software cpu-clock event instead:
<code>
# /root/linux/tools/perf/perf record -e cpu-clock -a factor 2365873330313
2365873330313: 4567 518036639
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.119 MB perf.data (152 samples) ]
\o/
</code>