--- a/b2g/config/mozconfigs/linux32_gecko/nightly
+++ b/b2g/config/mozconfigs/linux32_gecko/nightly
@@ -11,19 +11,16 @@ ac_add_options --enable-signmar
 # Avoid dependency on libstdc++ 4.5
 ac_add_options --enable-stdcxx-compat
 
 # This will overwrite the default of stripping everything and keep the symbol table.
 # This is useful for profiling and debugging and only increases the package size
 # by 2 MBs.
 STRIP_FLAGS="--strip-debug"
 
-# PGO
-mk_add_options PROFILE_GEN_SCRIPT='$(PYTHON) @MOZ_OBJDIR@/_profile/pgo/profileserver.py 10'
-
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
 export MOZ_TELEMETRY_REPORTING=1
 
 # Treat warnings as errors in directories with FAIL_ON_WARNINGS.
 # DISABLED WHILE NOT ON TRY ac_add_options --enable-warnings-as-errors
 

--- a/b2g/config/mozconfigs/linux64_gecko/nightly
+++ b/b2g/config/mozconfigs/linux64_gecko/nightly
@@ -11,19 +11,16 @@ ac_add_options --enable-signmar
 # Avoid dependency on libstdc++ 4.5
 ac_add_options --enable-stdcxx-compat
 
 # This will overwrite the default of stripping everything and keep the symbol table.
 # This is useful for profiling and debugging and only increases the package size
 # by 2 MBs.
 STRIP_FLAGS="--strip-debug"
 
-# PGO
-mk_add_options PROFILE_GEN_SCRIPT='$(PYTHON) @MOZ_OBJDIR@/_profile/pgo/profileserver.py 10'
-
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
 export MOZ_TELEMETRY_REPORTING=1
 
 # Treat warnings as errors in directories with FAIL_ON_WARNINGS.
 # DISABLED WHILE NOT ON TRY ac_add_options --enable-warnings-as-errors
 

--- a/b2g/config/mozconfigs/win32_gecko/nightly
+++ b/b2g/config/mozconfigs/win32_gecko/nightly
@@ -1,13 +1,10 @@
 . "$topsrcdir/b2g/config/mozconfigs/common"
 
-# for pgo
-mk_add_options PROFILE_GEN_SCRIPT='$(PYTHON) $(MOZ_OBJDIR)/_profile/pgo/profileserver.py'
-
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
 ac_add_options --enable-update-packaging
 ac_add_options --enable-jemalloc
 ac_add_options --enable-signmar
 
 # Nightlies only since this has a cost in performance
 ac_add_options --enable-js-diagnostics
 

--- a/browser/config/mozconfigs/linux32/nightly
+++ b/browser/config/mozconfigs/linux32/nightly
@@ -11,19 +11,16 @@ ac_add_options --enable-js-diagnostics
 # Avoid dependency on libstdc++ 4.5
 ac_add_options --enable-stdcxx-compat
 
 # This will overwrite the default of stripping everything and keep the symbol table.
 # This is useful for profiling and debugging and only increases the package size
 # by 2 MBs.
 STRIP_FLAGS="--strip-debug"
 
-# PGO
-mk_add_options PROFILE_GEN_SCRIPT='EXTRA_TEST_ARGS=10 $(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
-
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
 export MOZ_TELEMETRY_REPORTING=1
 
 # Treat warnings as errors in directories with FAIL_ON_WARNINGS.
 ac_add_options --enable-warnings-as-errors
 

--- a/browser/config/mozconfigs/linux32/qt
+++ b/browser/config/mozconfigs/linux32/qt
@@ -4,19 +4,16 @@ ac_add_options --enable-codesighs
 . $topsrcdir/build/unix/mozconfig.linux32
 
 # Avoid dependency on libstdc++ 4.5
 ac_add_options --enable-stdcxx-compat
 
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
-# PGO
-mk_add_options PROFILE_GEN_SCRIPT='EXTRA_TEST_ARGS=10 $(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
-
 #Use ccache
 ac_add_options --with-ccache=/usr/bin/ccache
 
 # QT Options
 export PKG_CONFIG_PATH=/tools/qt-4.6.3/qt/lib/pkgconfig
 ac_add_options --with-qtdir=/tools/qt-4.6.3/qt
 ac_add_options --enable-default-toolkit=cairo-qt
 ac_add_options --disable-crashreporter

--- a/browser/config/mozconfigs/linux32/release
+++ b/browser/config/mozconfigs/linux32/release
@@ -2,19 +2,17 @@ ac_add_options --enable-update-channel=$
 ac_add_options --enable-update-packaging
 ac_add_options --enable-official-branding
 
 . $topsrcdir/build/unix/mozconfig.linux32
 
 # Avoid dependency on libstdc++ 4.5
 ac_add_options --enable-stdcxx-compat
 
-# PGO
 mk_add_options MOZ_PGO=1
-mk_add_options PROFILE_GEN_SCRIPT='EXTRA_TEST_ARGS=10 $(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
 
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
 export MOZ_TELEMETRY_REPORTING=1
 
 # Treat warnings as errors in directories with FAIL_ON_WARNINGS.
 ac_add_options --enable-warnings-as-errors

--- a/browser/config/mozconfigs/linux32/rpm
+++ b/browser/config/mozconfigs/linux32/rpm
@@ -14,17 +14,15 @@ ac_add_options --libdir=$LIBDIR
 # Avoid dependency on libstdc++ 4.5
 ac_add_options --enable-stdcxx-compat
 
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
 export MOZ_TELEMETRY_REPORTING=1
 
-mk_add_options PROFILE_GEN_SCRIPT='$(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
-
 #Use ccache
 ac_add_options --with-ccache=/usr/bin/ccache
 
 # Treat warnings as errors in directories with FAIL_ON_WARNINGS.
 ac_add_options --enable-warnings-as-errors
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/linux64/nightly
+++ b/browser/config/mozconfigs/linux64/nightly
@@ -11,19 +11,16 @@ ac_add_options --enable-js-diagnostics
 # Avoid dependency on libstdc++ 4.5
 ac_add_options --enable-stdcxx-compat
 
 # This will overwrite the default of stripping everything and keep the symbol table.
 # This is useful for profiling and debugging and only increases the package size
 # by 2 MBs.
 STRIP_FLAGS="--strip-debug"
 
-# PGO
-mk_add_options PROFILE_GEN_SCRIPT='EXTRA_TEST_ARGS=10 $(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
-
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
 export MOZ_TELEMETRY_REPORTING=1
 
 # Treat warnings as errors in directories with FAIL_ON_WARNINGS.
 ac_add_options --enable-warnings-as-errors
 

--- a/browser/config/mozconfigs/linux64/release
+++ b/browser/config/mozconfigs/linux64/release
@@ -2,19 +2,17 @@ ac_add_options --enable-update-channel=$
 ac_add_options --enable-update-packaging
 ac_add_options --enable-official-branding
 
 . $topsrcdir/build/unix/mozconfig.linux
 
 # Avoid dependency on libstdc++ 4.5
 ac_add_options --enable-stdcxx-compat
 
-# PGO
 mk_add_options MOZ_PGO=1
-mk_add_options PROFILE_GEN_SCRIPT='EXTRA_TEST_ARGS=10 $(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
 
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
 export MOZ_TELEMETRY_REPORTING=1
 
 # Treat warnings as errors in directories with FAIL_ON_WARNINGS.
 ac_add_options --enable-warnings-as-errors

--- a/browser/config/mozconfigs/linux64/rpm
+++ b/browser/config/mozconfigs/linux64/rpm
@@ -14,17 +14,15 @@ ac_add_options --libdir=$LIBDIR
 # Avoid dependency on libstdc++ 4.5
 ac_add_options --enable-stdcxx-compat
 
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
 export MOZ_TELEMETRY_REPORTING=1
 
-mk_add_options PROFILE_GEN_SCRIPT='$(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
-
 #Use ccache
 ac_add_options --with-ccache=/usr/bin/ccache
 
 # Treat warnings as errors in directories with FAIL_ON_WARNINGS.
 ac_add_options --enable-warnings-as-errors
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/win32/nightly
+++ b/browser/config/mozconfigs/win32/nightly
@@ -1,13 +1,10 @@
 . "$topsrcdir/browser/config/mozconfigs/common"
 
-# for pgo
-mk_add_options PROFILE_GEN_SCRIPT='$(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
-
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
 ac_add_options --enable-update-packaging
 ac_add_options --enable-jemalloc
 ac_add_options --enable-signmar
 
 # Nightlies only since this has a cost in performance
 ac_add_options --enable-js-diagnostics
 

--- a/browser/config/mozconfigs/win32/release
+++ b/browser/config/mozconfigs/win32/release
@@ -1,13 +1,11 @@
 . "$topsrcdir/browser/config/mozconfigs/common"
 
-# for pgo
 mk_add_options MOZ_PGO=1
-mk_add_options PROFILE_GEN_SCRIPT='$(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
 
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
 ac_add_options --enable-update-packaging
 ac_add_options --enable-jemalloc
 ac_add_options --enable-official-branding
 
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1

--- a/browser/config/mozconfigs/win64/nightly
+++ b/browser/config/mozconfigs/win64/nightly
@@ -1,16 +1,13 @@
 . "$topsrcdir/browser/config/mozconfigs/common"
 
 ac_add_options --target=x86_64-pc-mingw32
 ac_add_options --host=x86_64-pc-mingw32
 
-# for pgo
-mk_add_options PROFILE_GEN_SCRIPT='$(MAKE) -C $(MOZ_OBJDIR) pgo-profile-run'
-
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
 ac_add_options --enable-update-packaging
 ac_add_options --enable-jemalloc
 ac_add_options --enable-signmar
 
 # Nightlies only since this has a cost in performance
 ac_add_options --enable-js-diagnostics
 

deleted file mode 100644
--- a/build/profile_pageloader.html
+++ /dev/null
@@ -1,11 +0,0 @@
-<!-- This Source Code Form is subject to the terms of the Mozilla Public
-   - License, v. 2.0. If a copy of the MPL was not distributed with this
-   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
-
-<html>
-<script>
-setTimeout("window.close();", 1000);
-</script>
-<body>
-</body>
-</html>

deleted file mode 100755
--- a/build/profile_pageloader.pl
+++ /dev/null
@@ -1,177 +0,0 @@
-#!/usr/bin/perl
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-use Cwd;
-use File::Find ();
-
-use POSIX qw(sys_wait_h);
-
-sub kill_process {
-    my ($target_pid) = @_;
-    my $start_time = time;
-
-    # Try to kill and wait 10 seconds, then try a kill -9
-    my $sig;
-    for $sig ('TERM', 'KILL') {
-        print "kill $sig $target_pid\n";
-        kill $sig => $target_pid;
-        my $interval_start = time;
-        while (time - $interval_start < 10) {
-            # the following will work with 'cygwin' perl on win32, but not
-            # with 'MSWin32' (ActiveState) perl
-            my $pid = waitpid($target_pid, POSIX::WNOHANG());
-            if (($pid == $target_pid and POSIX::WIFEXITED($?)) or $pid == -1) {
-                my $secs = time - $start_time;
-                $secs = $secs == 1 ? '1 second' : "$secs seconds";
-                print "Process killed. Took $secs to die.\n";
-                return;
-            }
-            sleep 1;
-        }
-    }
-    die "Unable to kill process: $target_pid";
-}
-
-# Stripped down version of fork_and_log().
-sub system_fork_and_log {
-    # Fork a sub process and log the output.
-    my ($cmd) = @_;
-
-    my $pid = fork; # Fork off a child process.
-
-    unless ($pid) { # child
-        exec { $cmd->[0] } @$cmd;
-        die "Could not exec()";
-    }
-    return $pid;
-}
-
-
-sub wait_for_pid {
-    # Wait for a process to exit or kill it if it takes too long.
-    my ($pid, $timeout_secs) = @_;
-    my ($exit_value, $signal_num, $dumped_core, $timed_out) = (0,0,0,0);
-    my $sig_name;
-    my $loop_count;
-
-    die ("Invalid timeout value passed to wait_for_pid()\n")
-        if ($timeout_secs <= 0);
-
-    eval {
-        $loop_count = 0;
-        while (++$loop_count < $timeout_secs) {
-            my $wait_pid = waitpid($pid, POSIX::WNOHANG());
-            # the following will work with 'cygwin' perl on win32, but not 
-            # with 'MSWin32' (ActiveState) perl
-            last if ($wait_pid == $pid and POSIX::WIFEXITED($?)) or $wait_pid == -1;
-            sleep 1;
-        }
-
-        $exit_value = $? >> 8;
-        $signal_num = $? >> 127;
-        $dumped_core = $? & 128;
-        if ($loop_count >= $timeout_secs) {
-            die "timeout";
-        }
-        return "done";
-    };
-
-    if ($@) {
-        if ($@ =~ /timeout/) {
-            kill_process($pid);
-            $timed_out = 1;
-        } else { # Died for some other reason.
-            die; # Propagate the error up.
-        }
-    }
-#    $sig_name = $signal_num ? signal_name($signal_num) : '';
-#
-#    return { timed_out=>$timed_out,
-#             exit_value=>$exit_value,
-#             sig_name=>$sig_name,
-#             dumped_core=>$dumped_core };
-}
-
-# System version of run_cmd().
-sub run_system_cmd {
-    my ($cmd, $timeout_secs) = @_;
-
-#    print_log "cmd = $cmd\n";
-    my $pid = system_fork_and_log($cmd);
-    my $result = wait_for_pid($pid, $timeout_secs);
-
-    return $result;
-}
-
-#
-# Given profile directory, find pref file hidden in salt directory.
-# profile $Settings::MozProfileName must exist before calling this sub.
-#
-sub find_pref_file {
-    my $profile_dir = shift;
-
-    # default to *nix
-    my $pref_file = "prefs.js";
-
-    unless (-e $profile_dir) {
-        return; # empty list
-    }
-
-    my $found = undef;
-    my $sub = sub {$pref_file = $File::Find::name, $found++ if $pref_file eq $_};
-    File::Find::find($sub, $profile_dir);
-    unless ($found) {
-        return; # empty list
-    }
-
-    return $pref_file;
-}
-
-my $topdir = cwd();
-
-chdir $ENV{OBJDIR};
-my $app_name = `grep "MOZ_APP_NAME	" config/autoconf.mk | sed "s/.*= //"`;
-chomp($app_name);
-
-# On mac, the app directory is the product name with the first
-# letter capitalized
-
-my $toolkit = `grep "MOZ_WIDGET_TOOLKIT        " config/autoconf.mk  |sed "s/.*= //"`;
-chomp($toolkit);
-
-if ($toolkit =~ /(mac|cocoa)/) {
-    my $app_dir = uc(substr($app_name, 0, 1)).substr($app_name, 1);
-    chdir "dist/$app_dir.app/Contents/MacOS";
-} else {
-    chdir "dist/bin";
-}
-
-my $bin_suffix = "";
-if ($toolkit =~ /(windows|os2)/) {
-    $bin_suffix = ".exe";
-}
-
-my $old_home = $ENV{HOME};
-$ENV{HOME} = cwd();
-
-# Create a profile to test with.
-run_system_cmd(["./".$app_name.$bin_suffix, "-createProfile", "testprofile"], 45);
-
-my $pref_file = find_pref_file(".mozilla/".$app_name);
-open PREFS, ">>$pref_file";
-# Add allow_scripts_to_close_windows; this lets us cleanly exit.
-print PREFS "user_pref(\"dom.allow_scripts_to_close_windows\", true);\n";
-# Suppress the default browser dialog since it keeps the test from starting.
-print PREFS "user_pref(\"browser.shell.checkDefaultBrowser\", false);\n";
-close PREFS;
-
-# Run the pageload test.
-run_system_cmd(["./".$app_name.$bin_suffix, $ENV{PAGELOAD_URL}."/loader.pl?maxcyc=2&delay=500&nocache=0&timeout=30000&auto=1"], 240);
-
-# Start up again; this will gather data for reading global history and
-# reading the fastload file.
-run_system_cmd(["./".$app_name.$bin_suffix, "file://$topdir/build/profile_pageloader.html"], 45);
-
-chdir $topdir;

--- a/client.mk
+++ b/client.mk
@@ -183,36 +183,30 @@ clobber clobber_all: clean
 # helper target for mobile
 build_and_deploy: build fast-package install
 
 # Do everything from scratch
 everything: clean build
 
 ####################################
 # Profile-Guided Optimization
-#  To use this, you should set the following variables in your mozconfig
-#    mk_add_options PROFILE_GEN_SCRIPT=/path/to/profile-script
-#
-#  The profile script should exercise the functionality to be included
-#  in the profile feedback.
-#
 #  This is up here, outside of the MOZ_CURRENT_PROJECT logic so that this
 #  is usable in multi-pass builds, where you might not have a runnable
 #  application until all the build passes and postflight scripts have run.
 ifdef MOZ_OBJDIR
   PGO_OBJDIR = $(MOZ_OBJDIR)
 else
   PGO_OBJDIR := $(TOPSRCDIR)
 endif
 
 profiledbuild::
 	$(MAKE) -f $(TOPSRCDIR)/client.mk realbuild MOZ_PROFILE_GENERATE=1 MOZ_PGO_INSTRUMENTED=1
 	$(MAKE) -C $(PGO_OBJDIR) package MOZ_PGO_INSTRUMENTED=1 MOZ_INTERNAL_SIGNING_FORMAT= MOZ_EXTERNAL_SIGNING_FORMAT=
 	rm -f ${PGO_OBJDIR}/jarlog/en-US.log
-	MOZ_PGO_INSTRUMENTED=1 OBJDIR=${PGO_OBJDIR} JARLOG_FILE=${PGO_OBJDIR}/jarlog/en-US.log $(PROFILE_GEN_SCRIPT)
+	MOZ_PGO_INSTRUMENTED=1 JARLOG_FILE=jarlog/en-US.log EXTRA_TEST_ARGS=10 $(MAKE) -C $(PGO_OBJDIR) pgo-profile-run
 	$(MAKE) -f $(TOPSRCDIR)/client.mk maybe_clobber_profiledbuild
 	$(MAKE) -f $(TOPSRCDIR)/client.mk realbuild MOZ_PROFILE_USE=1
 
 #####################################################
 # Build date unification
 
 ifdef MOZ_UNIFY_BDATE
 ifndef MOZ_BUILD_DATE