Provided by: systemtap-doc_2.3-1ubuntu1.4_all 

NAME
probe::nfs.fop.sendfile - NFS client send file operation
SYNOPSIS
nfs.fop.sendfile
VALUES
count
read bytes
dev
device identifier
cache_valid
cache related bit mask flag
attrtimeo
how long the cached information is assumed to be valid. We need to revalidate the cached attrs for
this inode if jiffies - read_cache_jiffies > attrtimeo.
cache_time
when we started read-caching this inode
ino
inode number
ppos
current position of file
SystemTap Tapset Reference March 2016 PROBE::NFS.FOP.S(3stap)