- Use prctl to set the lwp/thread name under Linux. This makes the

  threads easily identifiable in top.

lib/logstash/util.rb

@@ -1,11 +1,32 @@
 require "logstash/namespace"
+require "ffi" # gem ffi
+require "sys/uname" # gem sys-uname
 
 module LogStash::Util
+  PR_SET_NAME = 15
+  UNAME = Sys::Uname.uname.sysname
+
+  module LibC
+    extend FFI::Library
+    if UNAME == "Linux"
+      ffi_lib 'c'
+
+      # Ok so the 2nd arg isn't really a string... but whaatever
+      attach_function :prctl, [:int, :string, :long, :long, :long], :int
+    end
+  end
+
   def self.set_thread_name(name)
     if RUBY_ENGINE == "jruby"
       # Keep java and ruby thread names in sync.
       Java::java.lang.Thread.currentThread.setName(name)
     end
     Thread.current[:name] = name
+
+    if UNAME == "Linux"
+      # prctl PR_SET_NAME allows up to 16 bytes for a process name
+      # since MRI 1.9 and JRuby use system threads for this.
+      LibC.prctl(PR_SET_NAME, name[0..16], 0, 0, 0)
+    end
   end # def set_thread_name
 end # module LogStash::Util

logstash.gemspec

@@ -22,6 +22,7 @@ Gem::Specification.new do |gem|
   gem.add_runtime_dependency "minitest" # for running the tests from the jar
   gem.add_runtime_dependency "pry"
   gem.add_runtime_dependency "stud"
+  gem.add_runtime_dependency "sys-uname" # for platform detection
 
   # Web dependencies
   gem.add_runtime_dependency "ftw", ["~> 0.0.26"]