diff --git a/Gemfile b/Gemfile
index 130623c..2c12bbe 100644
--- a/Gemfile
+++ b/Gemfile
@@ -16,6 +16,7 @@ group :development, :test do
   gem "test-unit"
   gem "ci_reporter"
   gem "ruby-prof" unless RUBY_PLATFORM =~ /java/
+  gem "perftools.rb" unless RUBY_PLATFORM =~ /java/
 
   # Java
   platforms :jruby do
diff --git a/bench/exp_series.html b/bench/exp_series.html
index abceb8c..c3f4bfb 100644
--- a/bench/exp_series.html
+++ b/bench/exp_series.html
@@ -27,16 +27,22 @@
     <div id="placeholder"></div>
 
 <script type="text/javascript">
-    function genOpXY(a, xMax, base, gen, op, xKey, yKey) {
-        var genOpA = $.grep(a, function(e, i){return (e.exp2 <= xMax && e.base == base && e.generator == gen && e.operation == op);});
+    function genOpXY(a, xMax, plotSpec, xKey, yKey) {
+        var genOpA = $.grep(a, function(e, i){
+            if (e.exp2 > xMax) return false;
+            for (var key in plotSpec) {
+                if (e[key] != plotSpec[key]) return false;
+            }
+            return true;
+        });
         return $.map(genOpA, function(e, i){return [[e[xKey], e[yKey]]];});
     }
-    function flotSeries(expSeries, xMax, a) {
-        return $.map(a, function(e, i){
-            var base = e[0]; gen = e[1]; var op = e[2];
+    function flotSeries(expSeries, xMax, plotSpecs) {
+        return $.map(plotSpecs, function(plotSpec, i){
+            var base = plotSpec.base; var gen = plotSpec.generator; var op = plotSpec.operation;
             return {
                 label: gen + '-' + base,
-                data: genOpXY(expSeries, xMax, base, gen, op, 'exp2', 'ops'),
+                data: genOpXY(expSeries, xMax, plotSpec, 'exp2', 'ops'),
                 lines: { show: true },
                 points: { show: true }
             };
@@ -66,50 +72,56 @@ $(function () {
 
     // comment pending
     var graph = [
-        [ 'value_string_size insert', 14, [
-                [2, 'value_string_size', 'insert']
+        [ 'value_string_size insert C', 14,
+            [
+                { base:2, generator:'value_string_size', operation:'insert', mongo_driver_mode: 'c' }
             ]
         ],
-        [ 'key_string_size insert', 14, [
-                [2, 'key_string_size', 'insert']
+        [ 'key_string_size insert C', 14,
+            [
+                { base:2, generator:'key_string_size', operation:'insert', mongo_driver_mode: 'c' }
             ]
         ],
-        [ 'array_size_fixnum insert', 12, [
-                [2, 'array_size_fixnum', 'insert']
+        [ 'array_size_fixnum insert C', 12,
+            [
+                { base:2, generator:'array_size_fixnum', operation:'insert', mongo_driver_mode: 'c' }
             ]
         ],
-        [ 'hash_size_fixnum insert', 12, [
-                [2, 'hash_size_fixnum', 'insert']
+        [ 'hash_size_fixnum insert C', 12,
+            [
+                { base:2, generator:'hash_size_fixnum', operation:'insert', mongo_driver_mode: 'c' }
             ]
         ],
-        [ 'array_nest_fixnum insert', 12, [
-                [2, 'array_nest_fixnum', 'insert'],
-                [4, 'array_nest_fixnum', 'insert'],
-                [8, 'array_nest_fixnum', 'insert'],
-                [16, 'array_nest_fixnum', 'insert'],
-                [32, 'array_nest_fixnum', 'insert']
+        [ 'array_nest_fixnum insert C', 12,
+            [
+                { base:2, generator:'array_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' },
+                { base:4, generator:'array_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' },
+                { base:8, generator:'array_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' },
+                { base:16, generator:'array_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' },
+                { base:32, generator:'array_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' }
             ]
         ],
-        [ 'hash_nest_fixnum insert', 12, [
-                [2, 'hash_nest_fixnum', 'insert'],
-                [4, 'hash_nest_fixnum', 'insert'],
-                [8, 'hash_nest_fixnum', 'insert'],
-                [16, 'hash_nest_fixnum', 'insert'],
-                [32, 'hash_nest_fixnum', 'insert']
+        [ 'hash_nest_fixnum insert C', 12,
+            [
+                { base:2, generator:'hash_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' },
+                { base:4, generator:'hash_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' },
+                { base:8, generator:'hash_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' },
+                { base:16, generator:'hash_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' },
+                { base:32, generator:'hash_nest_fixnum', operation:'insert', mongo_driver_mode: 'c' }
             ]
         ],
-        [ 'compare array_size_fixnum hash_size_fixnum insert', 12, [
-                [2, 'array_size_fixnum', 'insert'],
-                [2, 'hash_size_fixnum', 'insert']
+        [ 'compare array_size_fixnum hash_size_fixnum insert C', 12,
+            [
+                { base:2, generator:'array_size_fixnum', operation:'insert', mongo_driver_mode: 'c' },
+                { base:2, generator:'hash_size_fixnum', operation:'insert', mongo_driver_mode: 'c' }
             ]
-        ],
-
+        ]
     ];
     $.each(graph, function(i, e){
         var title = e[0];
         var xMax = e[1];
-        var baseSeriesGenOp = e[2];
-        var series = flotSeries(expSeries, xMax, baseSeriesGenOp);
+        var plotSpecs = e[2];
+        var series = flotSeries(expSeries, xMax, plotSpecs);
         doPlot(title, series);
     });
 
diff --git a/bench/exp_series.js b/bench/exp_series.js
index bc80c16..1f607d5 100644
--- a/bench/exp_series.js
+++ b/bench/exp_series.js
@@ -1,137 +1,274 @@
 expSeries = [
-{"base":2,"power":0,"size":1,"exp2":0,"generator":"value_string_size","operation":"insert","iterations":136533,"utime":10.05,"etime":2.18,"rtime":13.99,"ops":13585.4,"usec":73.6},
-{"base":2,"power":1,"size":2,"exp2":1,"generator":"value_string_size","operation":"insert","iterations":136533,"utime":10.0,"etime":2.82,"rtime":12.5,"ops":13653.3,"usec":73.2},
-{"base":2,"power":2,"size":4,"exp2":2,"generator":"value_string_size","operation":"insert","iterations":136533,"utime":10.09,"etime":2.79,"rtime":14.45,"ops":13531.5,"usec":73.9},
-{"base":2,"power":3,"size":8,"exp2":3,"generator":"value_string_size","operation":"insert","iterations":136533,"utime":10.0,"etime":2.87,"rtime":12.39,"ops":13653.3,"usec":73.2},
-{"base":2,"power":4,"size":16,"exp2":4,"generator":"value_string_size","operation":"insert","iterations":136533,"utime":9.95,"etime":2.98,"rtime":12.09,"ops":13721.9,"usec":72.9},
-{"base":2,"power":5,"size":32,"exp2":5,"generator":"value_string_size","operation":"insert","iterations":136533,"utime":10.04,"etime":2.9,"rtime":12.73,"ops":13598.9,"usec":73.5},
-{"base":2,"power":6,"size":64,"exp2":6,"generator":"value_string_size","operation":"insert","iterations":136533,"utime":10.23,"etime":3.58,"rtime":15.43,"ops":13346.3,"usec":74.9},
-{"base":2,"power":7,"size":128,"exp2":7,"generator":"value_string_size","operation":"insert","iterations":136533,"utime":10.19,"etime":3.49,"rtime":12.44,"ops":13398.7,"usec":74.6},
-{"base":2,"power":8,"size":256,"exp2":8,"generator":"value_string_size","operation":"insert","iterations":136533,"utime":10.71,"etime":3.74,"rtime":17.6,"ops":12748.2,"usec":78.4},
-{"base":2,"power":9,"size":512,"exp2":9,"generator":"value_string_size","operation":"insert","iterations":127999,"utime":9.92,"etime":3.86,"rtime":16.04,"ops":12903.1,"usec":77.5},
-{"base":2,"power":10,"size":1024,"exp2":10,"generator":"value_string_size","operation":"insert","iterations":127999,"utime":10.39,"etime":5.85,"rtime":13.78,"ops":12319.4,"usec":81.2},
-{"base":2,"power":11,"size":2048,"exp2":11,"generator":"value_string_size","operation":"insert","iterations":113777,"utime":10.32,"etime":4.67,"rtime":17.28,"ops":11024.9,"usec":90.7},
-{"base":2,"power":12,"size":4096,"exp2":12,"generator":"value_string_size","operation":"insert","iterations":102399,"utime":10.47,"etime":21.54,"rtime":20.57,"ops":9780.2,"usec":102.2},
-{"base":2,"power":13,"size":8192,"exp2":13,"generator":"value_string_size","operation":"insert","iterations":73142,"utime":9.61,"etime":9.64,"rtime":18.79,"ops":7611.0,"usec":131.4},
-{"base":2,"power":14,"size":16384,"exp2":14,"generator":"value_string_size","operation":"insert","iterations":51200,"utime":10.02,"etime":9.1,"rtime":107.18,"ops":5109.8,"usec":195.7},
-{"base":2,"power":15,"size":32768,"exp2":15,"generator":"value_string_size","operation":"insert","iterations":34133,"utime":10.8,"etime":9.43,"rtime":169.25,"ops":3160.5,"usec":316.4},
-{"base":2,"power":0,"size":1,"exp2":0,"generator":"key_string_size","operation":"insert","iterations":128000,"utime":9.29,"etime":37.42,"rtime":12.43,"ops":13778.3,"usec":72.6},
-{"base":2,"power":1,"size":2,"exp2":1,"generator":"key_string_size","operation":"insert","iterations":136533,"utime":9.88,"etime":5.55,"rtime":12.64,"ops":13819.1,"usec":72.4},
-{"base":2,"power":2,"size":4,"exp2":2,"generator":"key_string_size","operation":"insert","iterations":146285,"utime":10.62,"etime":7.39,"rtime":13.45,"ops":13774.5,"usec":72.6},
-{"base":2,"power":3,"size":8,"exp2":3,"generator":"key_string_size","operation":"insert","iterations":146285,"utime":11.03,"etime":4.05,"rtime":15.9,"ops":13262.5,"usec":75.4},
-{"base":2,"power":4,"size":16,"exp2":4,"generator":"key_string_size","operation":"insert","iterations":128000,"utime":10.45,"etime":3.92,"rtime":17.96,"ops":12248.8,"usec":81.6},
-{"base":2,"power":5,"size":32,"exp2":5,"generator":"key_string_size","operation":"insert","iterations":128000,"utime":10.26,"etime":5.27,"rtime":13.0,"ops":12475.6,"usec":80.2},
-{"base":2,"power":6,"size":64,"exp2":6,"generator":"key_string_size","operation":"insert","iterations":136533,"utime":10.96,"etime":3.59,"rtime":17.6,"ops":12457.4,"usec":80.3},
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-{"base":2,"power":9,"size":512,"exp2":9,"generator":"key_string_size","operation":"insert","iterations":127999,"utime":10.16,"etime":6.84,"rtime":20.55,"ops":12598.3,"usec":79.4},
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+];
diff --git a/bench/exp_series.rb b/bench/exp_series.rb
index 0378ee4..9ceceb3 100644
--- a/bench/exp_series.rb
+++ b/bench/exp_series.rb
@@ -1,7 +1,24 @@
 #!/usr/bin/env ruby
-$LOAD_PATH[0, 0] = File.join(File.dirname(__FILE__), '..', 'lib')
-#
-# review load path
+$LOAD_PATH.unshift(File.expand_path("../../lib", __FILE__))
+
+def set_mongo_driver_mode(mode)
+  case mode
+    when :c
+      ENV.delete('TEST_MODE')
+      ENV['C_EXT'] = 'TRUE'
+    when :ruby
+      ENV['TEST_MODE'] = 'TRUE'
+      ENV.delete('C_EXT')
+    else
+      raise 'mode must be :c or :ruby'
+  end
+  ENV['MONGO_DRIVER_MODE'] = mode.to_s
+end
+
+$mode = ARGV[0].to_sym if ARGV[0]
+set_mongo_driver_mode($mode || :c)
+ENV['HOSTNAME'] = `uname -n`[/([^.]*)/,1]
+ENV['OSNAME'] = `uname -s`.strip
 
 # Exploratory/Experimental/Exponential tests for performance tuning
 
@@ -13,8 +30,31 @@ require 'benchmark'
 
 $calibration_runtime = 0.1
 $target_runtime = 5.0
-$db_name = "benchmark"
-$collection_name = "exp_series"
+$db_name = 'benchmark'
+$collection_name = 'exp_series'
+
+class Hash
+  def store_embedded(key, value)
+    case key
+      when /([^.]*)\.(.*)/
+        store($1, Hash.new) unless fetch($1, nil)
+        self[$1].store_embedded($2, value)
+      else
+        store(key, value)
+    end
+  end
+end
+
+def sys_info
+  h = Hash.new
+  if FileTest.executable?('/usr/sbin/sysctl')
+    text = `/usr/sbin/sysctl -a kern.ostype kern.version kern.hostname hw.machine hw.model hw.cputype hw.busfrequency hw.cpufrequency`
+    values = text.split(/\n/).collect{|line| /([^:]*) *[:=] *(.*)/.match(line)[1..2]}
+    h = Hash.new
+    values.each{|key, value| h.store_embedded(key, value) }
+  end
+  return h
+end
 
 class TestExpPerformance < Test::Unit::TestCase
 
@@ -67,22 +107,24 @@ class TestExpPerformance < Test::Unit::TestCase
       size, doc = generator.call(base, power)
       iterations, utime, rtime, etime = valuate(db, coll, setup, teardown) { operation.call(coll, doc) }
       result = {
-          "base" => base,
-          "power" => power,
-          "size" => size,
-          "exp2" => Math.log2(size).to_i,
-          "generator" => generator.name.to_s,
-          "operation" => operation.name.to_s,
-          "iterations" => iterations,
-          "utime" => utime.round(2),
-          "etime" => etime.round(2),
-          "rtime" => rtime.round(2),
-          "ops" => (iterations.to_f / utime.to_f).round(1),
-          "usec" => (1000000.0 * utime.to_f / iterations.to_f).round(1),
-          # "git" => git, # thinking
-          # "datetime" +> Time.now, # thinking
-          # "hostname" => hostname, # thinking
-          # "nbench-int" => nbench.int, # thinking
+          'base' => base,
+          'power' => power,
+          'size' => size,
+          'exp2' => Math.log2(size).to_i,
+          'generator' => generator.name.to_s,
+          'operation' => operation.name.to_s,
+          'iterations' => iterations,
+          'utime' => utime.round(2),
+          'etime' => etime.round(2),
+          'rtime' => rtime.round(2),
+          'ops' => (iterations.to_f / utime.to_f).round(1),
+          'usec' => (1000000.0 * utime.to_f / iterations.to_f).round(1),
+          'mongo_driver_mode' => ENV['MONGO_DRIVER_MODE'],
+          'hostname' => ENV['HOSTNAME'],
+          'osname' => ENV['OSNAME'],
+          # 'git' => git, # thinking
+          # 'datetime' +> Time.now, # thinking
+          # 'nbench-int' => nbench.int, # thinking
       }
       STDERR.puts result.inspect
       STDERR.flush
@@ -92,19 +134,19 @@ class TestExpPerformance < Test::Unit::TestCase
 
   def value_string_size(base, power)
     n = base ** power
-    return [n, {n.to_s => ("*" * n)}]
+    return [n, {n.to_s => ('*' * n)}]
   end
 
   def key_string_size(base, power)
     n = base ** power
-    return [n, {("*" * n) => n}]
+    return [n, {('*' * n) => n}]
   end
 
   def hash_size_fixnum(base, power)
     n = base ** power
     h = Hash.new
     (0...n).each { |i| h[i.to_s] = i }
-    return [n, h]
+    return [n, {n.to_s => h}] # embedded like array_size_fixnum
   end
 
   def array_size_fixnum(base, power)
@@ -166,10 +208,14 @@ class TestExpPerformance < Test::Unit::TestCase
   end
 
   # Performance Tuning Engineering
+  ## Completed
+  ### How to measure and compare pure Ruby versus C extension performance
+  ## Current Work Items
+  ### Profiling of C extension
   ## Overall Strategy
-  ### Prioritize/Review Ruby 1.9.3, Ruby 1.8.7, JRuby 1.6.7
+  ### Prioritize/Review Ruby 1.9.3, JRuby 1.6.7, Ruby 1.8.7
   ### Run spectrum of exploratory performance tests
-  ### Graph results, probably with gnuplot, with HTML wrapper
+  ### Graph results with flot in HTML wrapper - http://code.google.com/p/flot/
   ### Select test for profiling
   ### Find where time is being spent
   ### Construct specific performance test
@@ -185,9 +231,14 @@ class TestExpPerformance < Test::Unit::TestCase
   ### Knowledge of Ruby driver and techniques
   ### Perhaps architecture and design improvements
   ### Lessons transferable to other drivers
+  ## HW Info
+  ### Linux - /proc/cpuinfo
+  ### Mac OS X - sysctl -a hw
 
   def test_zzz_exp_blanket
     puts
+    puts sys_info
+
     conn = Mongo::Connection.new
     conn.drop_database($db_name)
     db = conn.db($db_name)
@@ -222,13 +273,13 @@ class TestExpPerformance < Test::Unit::TestCase
     ]
     results = []
     tests.each do |base, max_power, generator, setup, operation, teardown|
-      # consider moving "method" as permitted by scope
+      # consider moving 'method' as permitted by scope
       results += power_test(base, max_power, db, coll, method(generator), method(setup), method(operation), method(teardown))
     end
     # consider inserting the results into a database collection
     # Test::Unit::TestCase pollutes STDOUT, so write to a file
-    File.open("exp_series.js", "w"){|f|
-        f.puts("expSeries = #{results.to_json.gsub(/(\[|},)/, "\\1\n")};")
+    File.open("exp_series-#{Time.now.strftime('%Y%m%d-%H%M')}.js", 'w'){|f|
+      f.puts("#{results.to_json.gsub(/\[/, "").gsub(/(}[\],])/, "},\n")}")
     }
 
     conn.drop_database($db_name)
diff --git a/bench/profile_array.rb b/bench/profile_array.rb
index 3f79d4d..4d7e2d9 100644
--- a/bench/profile_array.rb
+++ b/bench/profile_array.rb
@@ -1,10 +1,28 @@
 #!/usr/bin/env ruby
 $LOAD_PATH.unshift(File.expand_path("../../lib", __FILE__))
 
+def set_mongo_driver_mode(mode)
+  case mode
+    when :c
+      ENV.delete('TEST_MODE')
+      ENV['C_EXT'] = 'TRUE'
+    when :ruby
+      ENV['TEST_MODE'] = 'TRUE'
+      ENV.delete('C_EXT')
+    else
+      raise 'mode must be :c or :ruby'
+  end
+  ENV['MONGO_DRIVER_MODE'] = mode.to_s
+end
+
+$mode = ARGV[0].to_sym if ARGV[0]
+set_mongo_driver_mode($mode || :c)
+
 require 'rubygems'
 require 'mongo'
 require 'benchmark'
 require 'ruby-prof'
+require 'perftools'
 
 def array_size_fixnum(base, power)
   n = base ** power
@@ -21,7 +39,7 @@ def insert(coll, h)
   coll.insert(h) # note that insert stores :_id in h and subsequent inserts are updates
 end
 
-def profile(iterations)
+def ruby_prof(iterations)
   RubyProf.start
   puts Benchmark.measure {
     iterations.times { yield }
@@ -37,6 +55,15 @@ def profile(iterations)
   printer.print(STDOUT, {})
 end
 
+def perftools(iterations)
+  profile_file_name = "/tmp/profile_array.perftools"
+  PerfTools::CpuProfiler.start(profile_file_name) do
+    iterations.times { yield }
+  end
+  cmd = "pprof.rb --ignore=IO --text \"#{profile_file_name}\""
+  system(cmd)
+end
+
 conn = Mongo::Connection.new
 
 db  = conn['benchmark']
@@ -46,7 +73,8 @@ coll.remove
 puts "coll.count: #{coll.count}"
 
 n, doc = array_size_fixnum(2, 6)
-profile(1000) { insert(coll, doc) }
+ruby_prof(1000) { insert(coll, doc) }
+#perftools(10000) { insert(coll, doc) }
 
 puts "coll.count: #{coll.count}"
 coll.remove