$ make && time /tmp/src/pin-2.14-71313-gcc.4.4.7-linux/pin -t ~/follow_io/follow_io.so -- ./experiments/xml/one_record/xpath1 ./experiments/xml/one_record/records.xml "//ssn" | less
$ make && time /tmp/src/pin-2.14-71313-gcc.4.4.7-linux/pin -t ~/follow_io/follow_io.so -- ./experiments/xml/one_record/xpath1 ./experiments/xml/one_record/records.xml "//name" | less
$ cat out.ldj | ./byte_usage.js
$ mv usage.json used_bytes.txt read_bytes.txt out.ldj experiments/xml/one_record/name/
the usage type is syscall > 0