libtracefs: Add CAST(x AS _COUNTER_) syntax to create values in histograms
Use the CAST() command of SQL to define which items in the select should
be cast as values and not keys. By casting the field as the special value
_COUNTER_, it will turn the selection item into a value.
For example:
SELECT common_pid, CAST(bytes_req AS _COUNTER_) FROM kmalloc
Will create:
echo 'hist:keys=common_pid:vals=bytes_req' > events/kmem/kmalloc/trigger
Link: https://lkml.kernel.org/r/20210803170606.694085-23-rostedt@goodmis.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
5 files changed
