simplify; comments

ch11/latency_tests/latency_test.sh

@@ -1,22 +1,22 @@
 #!/bin/bash
 # latency_test.sh
-# Originally sourced from OSADL: 
+# Originally sourced from OSADL [1]:
 #  https://www.osadl.org/uploads/media/mklatencyplot.bash
 # Lightly modified for our purposes.. this script is to be run via it's
 # wrapper script runtest.
 #----------------------------------------------------------------------
 # This program is part of the source code released for the book
-#  "Linux Kernel Programming"
+#  "Linux Kernel Programming" 2E
 #  (c) Author: Kaiwan N Billimoria
 #  Publisher:  Packt
 #  GitHub repository:
-#  https://github.com/PacktPublishing/Linux-Kernel-Programming
+#  https://github.com/PacktPublishing/Linux-Kernel-Programming_2E
 # 
 # For details, refer the book, Ch 11.
 #----------------------------------------------------------------------
 # Notes/Ref:
-# a) http://www.osadl.org/Create-a-latency-plot-from-cyclictest-hi.bash-script-for-latency-plot.0.html
-# b) Detailed slides on cyclictest, good for understanding latency and it's
+# [1] http://www.osadl.org/Create-a-latency-plot-from-cyclictest-hi.bash-script-for-latency-plot.0.html
+# [2] Detailed slides on cyclictest, good for understanding latency and it's
 # measurement: 'Using and Understanding the Real-Time Cyclictest Benchmark',
 # Rowand, Oct 2013: https://events.static.linuxfound.org/sites/events/files/slides/cyclictest.pdf
 name=$(basename $0)
@@ -31,14 +31,6 @@ title="$1"
  exit 1
 }
 
-which cyclictest >/dev/null && pfx="" || {
-pfx=~/rtl_llkd/rt-tests/                    # adjust as required !
- [ ! -x ${pfx}/cyclictest ] && {
-   echo "${name}: cyclictest not located, aborting..."
-   exit 1
- }
-}
-
 echo "--------------------------"
 echo "Test Title :: \"${title}\""
 echo "--------------------------"
@@ -54,9 +46,8 @@ loops=100000000
 # alternatively: run cyclictest by duration
 #duration=12h
 duration=1h
-duration=1m
-echo "sudo ${pfx}cyclictest --duration=${duration} -m -Sp90 -i200 -h400 -q >output"
-sudo ${pfx}cyclictest --duration=${duration} -m -Sp90 -i200 -h400 -q >output
+echo "sudo cyclictest --duration=${duration} -m -S -p90 -i200 -h400 -q >output"
+sudo cyclictest --duration=${duration} -m -S -p90 -i200 -h400 -q >output
 
 # 2. Get maximum latency
 min=$(grep "Min Latencies" output | tr " " "\n" | grep "^[0-9]" | sort -n | head -1 | sed s/^0*//)
@@ -83,6 +74,7 @@ done
 
 # 6. Create plot command header
 title="${title}: ${latstr} ; kernel: $(uname -r)"
+rm -f plotcmd plot_$(uname -r).png 2>/dev/null
 echo -n -e "set title \"${title}\"\n\
     set terminal png size 800,480\n\
     set xlabel \"Latency (us): min $min us, avg $avg us, max $max us\"\n\

ch11/latency_tests/runtest

@@ -1,19 +1,19 @@
 #!/bin/bash
 #----------------------------------------------------------------------
 # This program is part of the source code released for the book
-#  "Linux Kernel Programming"
+#  "Linux Kernel Programming" 2E
 #  (c) Author: Kaiwan N Billimoria
 #  Publisher:  Packt
 #  GitHub repository:
-#  https://github.com/PacktPublishing/Linux-Kernel-Programming
+#  https://github.com/PacktPublishing/Linux-Kernel-Programming_2E
 #
+# Wrapper over the cyclictest latency measurement script latency_test.sh.
 # For details, refer the book, Ch 11.
 #----------------------------------------------------------------------
 name=$(basename $0)
-LAT=.  #~/booksrc/ch11/latency_tests
 TIMEOUT_HOURS=1
 
-[ ! -f ${LAT}/latency_test.sh ] && {
+[[ ! -f latency_test.sh ]] && {
    echo "${name}: latency_test.sh script not present? aborting..."
    exit 1
 }
@@ -27,9 +27,10 @@ which stress >/dev/null 2>&1 || {
 }
 
 echo "================================================================="
-${LAT}/latency_test.sh "running 'stress'" &
+./latency_test.sh "running 'stress'" &
+
 CMD="stress --cpu 6 --io 2 --hdd 4 --hdd-bytes 1MB --vm 2 --vm-bytes 128M --timeout ${TIMEOUT_HOURS}h"
-(cd ${KSRC}
+(#cd ${KSRC}
 sync ; date
 echo "${CMD}"
 eval "${CMD}"