[pcp:master] new issue: Correct mem.vmstat.pgsteal* mem.vmstat.pgscan metrics on RHEL7 and Fedora 25 #github

[pcp:master] New Issue Created by wcohen ( https://github.com/wcohen ) :
#276 Correct mem.vmstat.pgsteal* mem.vmstat.pgscan metrics on RHEL7 and Fedora 25 ( https://github.com/performancecopilot/pcp/issues/276 )

PCP on x86_64 RHEL7 and Fedora 25 lists the following pgsteal metrics:

$ pminfo mem.vmstat|grep pgsteal mem.vmstat.pgsteal_dma mem.vmstat.pgsteal_dma32 mem.vmstat.pgsteal_high mem.vmstat.pgsteal_movable mem.vmstat.pgsteal_normal

However, doing pmval for each of these pgsteal metrics on RHEL7 and F25 return "No values available". Those metrics do not appear to line up with what /proc/vmstat provide for RHEL7 and F25:

RHEL7

$ more /proc/vmstat |grep pgsteal pgsteal_kswapd_dma 0 pgsteal_kswapd_dma32 0 pgsteal_kswapd_normal 0 pgsteal_kswapd_movable 0 pgsteal_direct_dma 0 pgsteal_direct_dma32 0 pgsteal_direct_normal 0 pgsteal_direct_movable 0

F25: $ more /proc/vmstat |grep pgsteal pgsteal_kswapd 3543984 pgsteal_direct 290756

For Fedora 25 the pgscan metrics don't match with what is available in /proc/vmstat:

[wcohen@santana perf]$ pminfo mem.vmstat|grep pgscan mem.vmstat.pgscan_direct_dma mem.vmstat.pgscan_direct_dma32 mem.vmstat.pgscan_direct_high mem.vmstat.pgscan_direct_movable mem.vmstat.pgscan_direct_normal mem.vmstat.pgscan_kswapd_dma mem.vmstat.pgscan_kswapd_dma32 mem.vmstat.pgscan_kswapd_high mem.vmstat.pgscan_kswapd_movable mem.vmstat.pgscan_kswapd_normal [wcohen@santana perf]$ more /proc/vmstat |grep pgscan pgscan_kswapd 3679442 pgscan_direct 424948 pgscan_direct_throttle 0