jruby hacks

gistfile1.sh

#jruby hacks

jps -ml #show java processes running

jstack <pid>  #get a jvm stack info

jruby -J-Djruby.reify.classes=true   # a flag that tell jruby to compile ruby classes to real (matching) java classes

jvisualvm #great profiling tool


ab -n 1000 -c 10 http://localhost:3000  #apache bench command to load up a server

jruby -S warble executable compile war # creating executable war
java -jar myapp.war #run the executable war
java -jar myapp.war --help


# hotline nsieger@engineyard.com

#jruby -S rails new myapp --template http://jruby.org


#produce a heap dump on running tomcat
jmap -dump:live,format=b,file=heap.bin <pid>




#some notes from rails conf
lsof -nPp <pid>

tcpdump -i eth0 -s 0 -nqA

tcpdump -w <file>
then wireshark the file

strace -cp <pid>
strace -ttTp <pid> -o <file>

ltrace -cp <pid>
ltrace -c ruby threaded_em.rb
ltrace -ttT -e memcpy ruby threaded_em.rb

require 'rbtrace'
rbtrace -p <pid> -m <method>
rbtrace -p <pid> --slow=50
rbtrace -p <pid> -c <predefined tracer>

perftools from google feasible for production 

perftools.rb

gdb
gdb.rb

gem install memprof 
memprof.com

gem install hotspots