[PATCH] nfsiostat: display READ_PLUS statistics when available

[Karim Manaouil <kmanaouil.dev@gmail.com>]

NFSv4.2 mounts may report READ_PLUS operations separately from READ
in /proc/self/mountstats. nfsiostat parses these counters but does
not display them, leaving read activity out of its reports.

Display READ_PLUS in the default and page cache reports when the
operation is present. Document the conditional output.

Signed-off-by: Karim Manaouil <karim.manaouil@ed.ac.uk>
---
 tools/nfs-iostat/nfs-iostat.py | 4 ++++
 tools/nfs-iostat/nfsiostat.man | 5 ++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/nfs-iostat/nfs-iostat.py b/tools/nfs-iostat/nfs-iostat.py
index af04aac5..2a681bbe 100755
--- a/tools/nfs-iostat/nfs-iostat.py
+++ b/tools/nfs-iostat/nfs-iostat.py
@@ -436,6 +436,8 @@ class DeviceData:
 
         if which == 0:
             self.__print_rpc_op_stats('READ', sample_time, use_mb)
+            if 'READ_PLUS' in self.__rpc_data:
+                self.__print_rpc_op_stats('READ_PLUS', sample_time, use_mb)
             self.__print_rpc_op_stats('WRITE', sample_time, use_mb)
         elif which == 1:
             self.__print_rpc_op_stats('GETATTR', sample_time, use_mb)
@@ -449,6 +451,8 @@ class DeviceData:
             self.__print_dir_cache_stats(sample_time)
         elif which == 3:
             self.__print_rpc_op_stats('READ', sample_time, use_mb)
+            if 'READ_PLUS' in self.__rpc_data:
+                self.__print_rpc_op_stats('READ_PLUS', sample_time, use_mb)
             self.__print_rpc_op_stats('WRITE', sample_time, use_mb)
             self.__print_page_stats(sample_time)
 
diff --git a/tools/nfs-iostat/nfsiostat.man b/tools/nfs-iostat/nfsiostat.man
index 4f24318d..b06e65aa 100644
--- a/tools/nfs-iostat/nfsiostat.man
+++ b/tools/nfs-iostat/nfsiostat.man
@@ -10,6 +10,8 @@ nfsiostat \- Emulate iostat for NFS mount points using /proc/self/mountstats
 The
 .B nfsiostat
 command displays NFS client per-mount statistics. 
+The default report displays READ and WRITE statistics.  It also displays
+READ_PLUS when it is present in /proc/self/mountstats.
 .TP 
 <interval>
 specifies the amount of time in seconds between each report.
@@ -126,7 +128,8 @@ only print stats for first LIST mount points
 display throughput in megabytes per second
 .TP
 .B \-p " or " \-\-page
-displays statistics related to the page cache
+displays statistics related to the page cache, including READ_PLUS
+when it is present in /proc/self/mountstats
 .TP
 .B \-s " or " \-\-sort
 Sort NFS mount points by ops/second
-- 
2.47.3


-- 
~karim