-if some XXX_INTERVAL isn't specified, related stats won't be collected
-XXXX can be: VMSTAT, SERVICE, BRW, SDIO, MBALLOC, IO, JBD, CLIENT
+if XXX_INTERVAL isn't specified, XXX stats won't be collected
+XXX can be: VMSTAT, SERVICE, BRW, SDIO, MBALLOC, IO, JBD, CLIENT