Add nfs_threads command (#25)

Author: Don Brady

cmd/nfs_threads.py

@@ -0,0 +1,207 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2020 by Delphix. All rights reserved.
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+
+'''
+Display NFS thread usage info along with NFS I/O context.
+
+Output Sample:
+
+ packets  sockets threads threads metadata  read    read  write   write
+ arrived enqueued   woken   used     calls  iops thruput   iops thruput
+    4589        0    4589     25        16   273   3.6MB    212   2.6MB
+    4735        0    4735      8         1   287   3.8MB    212   2.7MB
+    4693        0    4693     10         0   280   3.7MB    216   2.7MB
+    4625        0    4625     15         0   278   3.7MB    212   2.6MB
+    4687        0    4687      7         1   285   3.8MB    210   2.6MB
+    4701        0    4701     12         0   285   3.8MB    215   2.7MB
+'''
+
+import psutil
+from signal import signal, SIGINT
+import sys
+from time import sleep
+
+POOL_STATS = "/proc/fs/nfsd/pool_stats"
+NFSD_STATS = "/proc/net/rpc/nfsd"
+
+H1 = ['packets', 'sockets', 'threads', 'threads', 'metadata', 'read',
+      'read', 'write', 'write']
+H2 = ['arrived', 'enqueued', 'woken', 'used', 'calls', 'iops', 'thruput',
+      'iops', 'thruput']
+
+INTERVAL = 5
+
+
+def server_stopped(message=''):
+    print("NFS Server Stopped {}".format(message))
+    sys.exit()
+
+
+def print_header(header):
+    for col in header:
+        print('{0:>10}'.format(col), end='')
+    print()
+
+
+def pool_stats():
+    try:
+        with open(POOL_STATS, "r") as file:
+            for line in file:
+                if not line.startswith("#"):
+                    fields = line.split(" ")
+                    packets = int(fields[1])
+                    enqueued = int(fields[2])
+                    woken = int(fields[3])
+                    timedout = int(fields[4])
+        return packets, enqueued, woken, timedout
+    except OSError:
+        server_stopped()
+
+
+def nfs_stats():
+    try:
+        metadata = 0
+        readops = 0
+        writeops = 0
+        with open(NFSD_STATS, "r") as file:
+            for line in file:
+                if line.startswith("io"):
+                    fields = line.split(" ")
+                    readbytes = int(fields[1])
+                    writebytes = int(fields[2])
+                if line.startswith("proc3"):
+                    fields = line.split(" ")
+                    readops += int(fields[8])
+                    writeops += int(fields[9])
+                    metadata += int(fields[3])
+                    metadata += int(fields[4])
+                    metadata += int(fields[5])
+                    metadata += int(fields[6])
+                    metadata += int(fields[20])
+                    metadata += int(fields[21])
+                    metadata += int(fields[22])
+                if line.startswith("proc4ops"):
+                    fields = line.split(" ")
+                    readops += int(fields[27])
+                    writeops += int(fields[40])
+                    metadata += int(fields[5])
+                    metadata += int(fields[8])
+                    metadata += int(fields[11])
+                    metadata += int(fields[17])
+                    metadata += int(fields[36])
+        return readbytes, writebytes, readops, writeops, metadata
+    except OSError:
+        server_stopped()
+
+
+def context_switches(pids):
+    "Return a list of context switches per process in pids"
+    ls = []
+    for pid in pids:
+        try:
+            pctxsw = psutil.Process(pid).num_ctx_switches()
+            ls.append(pctxsw.voluntary + pctxsw.involuntary)
+        except psutil.NoSuchProcess:
+            server_stopped()
+    return ls
+
+
+def nfsd_processes():
+    "Return a list of nfsd proceses"
+    ls = []
+    for p in psutil.process_iter(attrs=['name', 'pid', 'uids']):
+        if p.info['name'] == "nfsd" and p.info['uids'].real == 0:
+            ls.append(p.info['pid'])
+    return ls
+
+
+def print_value(value):
+    print('{0:>10}'.format(value), end='')
+
+
+def print_thruput(value):
+    if value > 1073741824:
+        print('{0:>8}GB'.format(round(value / 1073741824, 1)), end='')
+    elif value > 1048576:
+        print('{0:>8}MB'.format(round(value / 1048576, 1)), end='')
+    else:
+        print('{0:>8}KB'.format(int(value / 1024)), end='')
+
+
+def print_line():
+    pids = nfsd_processes()
+
+    prevSwitches = context_switches(pids)
+    prevPackets, prevEnqueued, prevWoken, prevTimedout = pool_stats()
+    prevRB, prevWB, prevRO, prevWO, prevMeta = nfs_stats()
+
+    while(not sleep(INTERVAL)):
+        nextSwitches = context_switches(pids)
+        nextPackets, nextEnqueued, nextWoken, nextTimedout = pool_stats()
+        nextRB, nextWB, nextRO, nextWO, nextMeta = nfs_stats()
+
+        threads = 0
+        for i in range(0, len(prevSwitches)):
+            if not prevSwitches[i] == nextSwitches[i]:
+                threads += 1
+        threads -= nextTimedout - prevTimedout
+        prevSwitches = nextSwitches.copy()
+
+        #
+        # The published 'sockets-enqueued' value needs adjustment
+        #
+        enqueued = (nextEnqueued - prevEnqueued) - (nextWoken - prevWoken)
+
+        #
+        # For IOPS values less than 10 display with decimal
+        #
+        readOps = (nextRO - prevRO) / INTERVAL
+        writeOps = (nextWO - prevWO) / INTERVAL
+        readOps = int(readOps) if readOps > 9 else round(readOps, 1)
+        writeOps = int(writeOps) if writeOps > 9 else round(writeOps, 1)
+
+        #
+        # The read/write values are published as a 32-bit
+        # value so account for it to wrap in the interval
+        #
+        if nextRB < prevRB:
+            prevRB = 0
+        if nextWB < prevWB:
+            prevWB = 0
+
+        print_value(nextPackets - prevPackets)
+        print_value(enqueued)
+        print_value(nextWoken - prevWoken)
+        print_value(threads)
+        print_value(nextMeta - prevMeta)
+        print_value(readOps)
+        print_thruput((nextRB - prevRB) / INTERVAL)
+        print_value(writeOps)
+        print_thruput((nextWB - prevWB) / INTERVAL)
+        print()
+
+        prevPackets = nextPackets
+        prevEnqueued = nextEnqueued
+        prevWoken = nextWoken
+        prevTimedout = nextTimedout
+        prevMeta = nextMeta
+        prevRB = nextRB
+        prevWB = nextWB
+        prevRO = nextRO
+        prevWO = nextWO
+
+
+def handler(signal_received, frame):
+    print()
+    sys.exit(0)
+
+
+signal(SIGINT, handler)
+
+print_header(H1)
+print_header(H2)
+print_line()

debian/control

@@ -13,6 +13,6 @@ Standards-Version: 4.1.2
 
 Package: performance-diagnostics
 Architecture: any
-Depends: python3-bcc, python-minimal
+Depends: python3-bcc, python-minimal, python3-psutil
 Description: eBPF-based Performance Diagnostic Tools
   A collection of eBPF-based tools for diagnosing performance issues.

debian/rules

@@ -16,6 +16,7 @@ override_dh_auto_build:
 	mkdir -p build/cmd/
 	cp cmd/estat.py build/cmd/estat
 	cp cmd/stbtrace.py build/cmd/stbtrace
+	cp cmd/nfs_threads.py build/cmd/nfs_threads
 
 override_dh_auto_install:
 	dh_install build/cmd/* /usr/bin