--- a/taskcluster/ci/test/raptor.yml
+++ b/taskcluster/ci/test/raptor.yml
@@ -978,36 +978,38 @@ raptor-jetstream2-firefox-profiling:
     mozharness:
         extra-options:
             - --test=raptor-jetstream2
             - --gecko-profile
     fetches:
         fetch:
             - jetstream2
 
-browsertime-tp6-1:
-    description: "Raptor (browsertime) tp6-1"
-    raptor-test: raptor-tp6-1
-    run-on-projects: ['mozilla-central','integration', 'try']
+browsertime-tp6:
+    description: "Raptor (browsertime) tp6 page-load tests"
+    raptor-test: tp6
+    raptor-subtests: ['amazon', 'bing-search', 'facebook', 'google-search',
+                      'google-slides', 'wikipedia', 'yahoo-news', 'youtube']
+    run-on-projects: ['mozilla-central', 'integration', 'try']
     apps: ['firefox', 'chrome']
     variants:
         by-app:
             firefox: ['fission']
             default: []
     pageload:
         by-app:
             firefox: 'both'
             chrome: 'cold'
             default: 'warm'
     limit-platforms:
         by-app:
             chrome:
                 - .*shippable[^-qr].*
             default: []
-    treeherder-symbol: Btime(tp6-1)
+    treeherder-symbol: Btime(tp6)
     max-run-time: 4000
     tier: 3
     condprof: True
     run-visual-metrics:
         by-app:
             chrome: false
             default: true
     mozharness:

--- a/taskcluster/ci/test/test-sets.yml
+++ b/taskcluster/ci/test/test-sets.yml
@@ -305,17 +305,17 @@ raptor-fetch-geckoview:
 
 raptor-fetch-chromium:
     - raptor-unity-webgl-chromium
     - raptor-wasm-misc-chromium
     - raptor-assorted-dom-chromium
     - raptor-jetstream2-chromium
 
 browsertime:
-    - browsertime-tp6-1
+    - browsertime-tp6
     - browsertime-speedometer
 
 # Raptor desktop power tests
 # (requires Intel Power Gadget to be pre-installed)
 raptor-firefox-power:
     - raptor-youtube-playback-v9-power-firefox
     - raptor-youtube-playback-h264-power-firefox
 

--- a/taskcluster/taskgraph/transforms/raptor.py
+++ b/taskcluster/taskgraph/transforms/raptor.py
@@ -23,16 +23,17 @@ transforms = TransformSequence()
 
 raptor_description_schema = Schema({
     # Raptor specific configs.
     Optional('apps'): optionally_keyed_by(
         'test-platform',
         [basestring]
     ),
     Optional('raptor-test'): basestring,
+    Optional('raptor-subtests'): [basestring],
     Optional('activity'): optionally_keyed_by(
         'app',
         basestring
     ),
     Optional('binary-path'): optionally_keyed_by(
         'app',
         basestring
     ),
@@ -152,17 +153,25 @@ def split_pageload(config, tests):
             continue
 
         if pageload == 'both':
             orig = deepcopy(test)
             yield orig
 
         assert 'raptor-test' in test
         test['description'] += " using cold pageload"
-        test['raptor-test'] += '-cold'
+
+        # for raptor-webext to run cold we just call the corresponding '-cold' test name; but
+        # for raptor browsertime we leave the raptor test name as/is and will set the '--cold'
+        # command line argument instead via settting test['cold'] to true
+        if test['test-name'].startswith('browsertime-tp6'):
+            test['cold'] = True
+        else:
+            test['raptor-test'] += '-cold'
+
         test['max-run-time'] = 3000
         test['test-name'] += '-cold'
         test['try-name'] += '-cold'
 
         group, symbol = split_symbol(test['treeherder-symbol'])
         symbol += '-c'
         test['treeherder-symbol'] = join_symbol(group, symbol)
         yield test
@@ -195,27 +204,66 @@ def build_condprof_tests(config, tests):
         condprof_test['try-name'] += '-condprof'
         condprof_test['test-name'] += '-condprof'
         condprof_test['treeherder-symbol'] = join_symbol(group, symbol)
 
         yield condprof_test
 
 
 @transforms.add
+def split_browsertime_page_load_by_url(config, tests):
+
+    for test in tests:
+
+        # for tests that have 'raptor-subtests' listed, we want to create a separate
+        # test job for every subtest (i.e. split out each page-load URL into its own job)
+        subtests = test.pop('raptor-subtests', None)
+        if not subtests:
+            yield test
+            continue
+
+        chunk_number = 0
+
+        for subtest in subtests:
+
+            # create new test job
+            chunked = deepcopy(test)
+
+            # only run the subtest/single URL
+            chunked['test-name'] += "-{}".format(subtest)
+            chunked['try-name'] += "-{}".format(subtest)
+            chunked['raptor-test'] = subtest
+
+            # set treeherder symbol and description
+            chunk_number += 1
+            group, symbol = split_symbol(test['treeherder-symbol'])
+            symbol += "-{}".format(chunk_number)
+            chunked['treeherder-symbol'] = join_symbol(group, symbol)
+            chunked['description'] += "-{}".format(subtest)
+
+            yield chunked
+
+
+@transforms.add
 def add_extra_options(config, tests):
     for test in tests:
         extra_options = test.setdefault('mozharness', {}).setdefault('extra-options', [])
 
         if test.pop('run-visual-metrics', False):
             extra_options.append('--browsertime-video')
             test['attributes']['run-visual-metrics'] = True
 
         if 'app' in test:
             extra_options.append('--app={}'.format(test.pop('app')))
 
+        # for browsertime tp6 cold page-load jobs we need to set the '--cold' cmd line arg
+        if test['test-name'].startswith('browsertime-tp6'):
+            if test.pop('cold', False) is True:
+                extra_options.append('--cold')
+
         if 'activity' in test:
             extra_options.append('--activity={}'.format(test.pop('activity')))
 
         if 'binary-path' in test:
             extra_options.append('--binary-path={}'.format(test.pop('binary-path')))
 
         if 'raptor-test' in test:
             extra_options.append('--test={}'.format(test.pop('raptor-test')))

--- a/testing/mozharness/mozharness/mozilla/testing/raptor.py
+++ b/testing/mozharness/mozharness/mozilla/testing/raptor.py
@@ -243,16 +243,22 @@ class Raptor(TestingMixin, MercurialScri
             "help": "Enable Fission (site isolation) in Gecko.",
         }],
         [["--setpref"], {
             "action": "append",
             "dest": "extra_prefs",
             "default": [],
             "help": "A preference to set. Must be a key-value pair separated by a ':'."
         }],
+        [["--cold"], {
+            "action": "store_true",
+            "dest": "cold",
+            "default": False,
+            "help": "Enable cold page-load for browsertime tp6",
+        }],
 
     ] + testing_config_options + \
         copy.deepcopy(code_coverage_config_options) + \
         browsertime_options
 
     def __init__(self, **kwargs):
         kwargs.setdefault('config_options', self.config_options)
         kwargs.setdefault('all_actions', ['clobber',
@@ -502,16 +508,18 @@ class Raptor(TestingMixin, MercurialScri
         if self.config.get('is_release_build', False):
             options.extend(['--is-release-build'])
         if self.config.get('power_test', False):
             options.extend(['--power-test'])
         if self.config.get('memory_test', False):
             options.extend(['--memory-test'])
         if self.config.get('cpu_test', False):
             options.extend(['--cpu-test'])
+        if self.config.get('cold', False):
+            options.extend(['--cold'])
         if self.config.get('enable_webrender', False):
             options.extend(['--enable-webrender'])
         if self.config.get('with_conditioned_profile', False):
             options.extend(['--with-conditioned-profile'])
         if self.config.get('enable_fission', False):
             options.extend(['--enable-fission'])
         if self.config.get('extra_prefs'):
             options.extend(['--setpref={}'.format(i) for i in self.config.get('extra_prefs')])

--- a/testing/raptor/raptor/cmdline.py
+++ b/testing/raptor/raptor/cmdline.py
@@ -151,16 +151,19 @@ def create_parser(mach_interface=False):
                 help="Flag which indicates if Raptor is running locally or in production")
         add_arg('--obj-path', dest="obj_path", default=None,
                 help="Browser-build obj_path (received when running in production)")
     add_arg('--noinstall', dest="noinstall", default=False, action="store_true",
             help="Flag which indicates if Raptor should not offer to install Android APK.")
     add_arg('--installerpath', dest="installerpath", default=None, type=str,
             help="Location where Android browser APK was extracted to before installation.")
 
+    # for browsertime jobs, cold page load is determined by a '--cold' cmd line argument
+    add_arg('--cold', dest="cold", action="store_true",
+            help="Enable cold page-load for browsertime tp6")
     # Arguments for invoking browsertime.
     add_arg('--browsertime', dest='browsertime', default=False, action="store_true",
             help="Whether to use browsertime to execute pageload tests")
     add_arg('--browsertime-node', dest='browsertime_node',
             help="path to Node.js executable")
     add_arg('--browsertime-browsertimejs', dest='browsertime_browsertimejs',
             help="path to browsertime.js script")
     add_arg('--browsertime-chromedriver', dest='browsertime_chromedriver',

--- a/testing/raptor/raptor/manifest.py
+++ b/testing/raptor/raptor/manifest.py
@@ -5,17 +5,17 @@ from __future__ import absolute_import
 
 import json
 import os
 
 from six.moves.urllib.parse import parse_qs, urlsplit, urlunsplit, urlencode, unquote
 
 from logger.logger import RaptorLogger
 from manifestparser import TestManifest
-from utils import transform_platform
+from utils import transform_platform, transform_subtest
 from constants.raptor_tests_constants import YOUTUBE_PLAYBACK_MEASURE
 
 here = os.path.abspath(os.path.dirname(__file__))
 raptor_ini = os.path.join(here, 'raptor.ini')
 tests_dir = os.path.join(here, 'tests')
 LOG = RaptorLogger(component='raptor-manifest')
 
 LIVE_SITE_TIMEOUT_MULTIPLIER = 1.2
@@ -308,16 +308,25 @@ def get_raptor_test_list(args, oskey):
 
     # go through each test and set the page-cycles and page-timeout, and some config flags
     # the page-cycles value in the INI can be overriden when debug-mode enabled, when
     # gecko-profiling enabled, or when --page-cycles cmd line arg was used (that overrides all)
     for next_test in tests_to_run:
         LOG.info("configuring settings for test %s" % next_test['name'])
         max_page_cycles = next_test.get('page_cycles', 1)
 
+        # if using playback, the playback recording info may need to be transformed
+        if next_test.get('playback') is not None:
+            next_test['playback_pageset_manifest'] = \
+                transform_subtest(next_test['playback_pageset_manifest'],
+                                  next_test['name'])
+            next_test['playback_recordings'] = \
+                transform_subtest(next_test['playback_recordings'],
+                                  next_test['name'])
+
         if args.gecko_profile is True:
             next_test['gecko_profile'] = True
             LOG.info('gecko-profiling enabled')
             max_page_cycles = 3
 
             if 'gecko_profile_entries' in args and args.gecko_profile_entries is not None:
                 next_test['gecko_profile_entries'] = str(args.gecko_profile_entries)
                 LOG.info('gecko-profiling entries set to %s' % args.gecko_profile_entries)
@@ -356,17 +365,30 @@ def get_raptor_test_list(args, oskey):
             LOG.info("setting page-timeout to %d as specified on cmd line" % args.page_timeout)
             next_test['page_timeout'] = args.page_timeout
 
         # if --browser-cycles was provided on the command line, use that instead of INI
         if args.browser_cycles is not None:
             LOG.info("setting browser-cycles to %d as specified on cmd line" % args.browser_cycles)
             next_test['browser_cycles'] = args.browser_cycles
 
-        if next_test.get("cold", "false") == "true":
+        # for browsertime jobs, cold page-load mode is determined by command line argument; for
+        # raptor-webext jobs cold page-load is determined by the 'cold' key in test manifest INI
+        _running_cold = False
+        if args.browsertime is True:
+            if args.cold is True:
+                _running_cold = True
+            else:
+                # running warm page-load so ignore browser-cycles if it was provided (set to 1)
+                next_test['browser_cycles'] = 1
+        else:
+            if next_test.get("cold", "false") == "true":
+                _running_cold = True
+
+        if _running_cold:
             # when running in cold mode, set browser-cycles to the page-cycles value; as we want
             # the browser to restart between page-cycles; and set page-cycles to 1 as we only
             # want 1 single page-load for every browser-cycle
             next_test['cold'] = True
             next_test['expected_browser_cycles'] = int(next_test['browser_cycles'])
             next_test['page_cycles'] = 1
             # also ensure '-cold' is in test name so perfherder results indicate warm cold-load
             if "-cold" not in next_test['name']:

--- a/testing/raptor/raptor/raptor.ini
+++ b/testing/raptor/raptor/raptor.ini
@@ -136,8 +136,11 @@
 
 # raptor scenario tests
 [include:tests/scenario/raptor-scn-power-idle.ini]
 [include:tests/scenario/raptor-scn-power-idle-bg.ini]
 
 # raptor unit tests
 # this is required for the manifest unit tests
 [include:tests/unittests/raptor-tp6-unittest.ini]
+
+# raptor-browsertime desktop tests
+[include:tests/tp6/desktop/browsertime-tp6.ini]

--- a/testing/raptor/raptor/raptor.py
+++ b/testing/raptor/raptor/raptor.py
@@ -620,16 +620,17 @@ class Browsertime(Perftest):
                 userjsfile.writelines(lines)
         except Exception as e:
             LOG.critical("Exception {} while removing mozprofile delimiters".format(e))
 
     def set_browser_test_prefs(self, raw_prefs):
         # add test specific preferences
         LOG.info("setting test-specific Firefox preferences")
         self.profile.set_preferences(json.loads(raw_prefs))
+        self.remove_mozprofile_delimiters_from_profile()
 
     def run_test_setup(self, test):
         super(Browsertime, self).run_test_setup(test)
 
         if test.get('type') == "benchmark":
             # benchmark-type tests require the benchmark test to be served out
             self.benchmark = Benchmark(self.config, test)
             test['test_url'] = test['test_url'].replace('<host>', self.benchmark.host)

new file mode 100644
--- /dev/null
+++ b/testing/raptor/raptor/tests/tp6/desktop/browsertime-tp6.ini
@@ -0,0 +1,48 @@
+# 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/.
+
+# raptor-browsertime tp6 desktop page-load test specification
+
+[DEFAULT]
+alert_on = fcp, loadtime
+alert_threshold = 2.0
+apps = firefox, chrome
+browser_cycles = 25
+gecko_profile_entries = 14000000
+gecko_profile_interval = 1
+lower_is_better = true
+measure = fnbpaint, fcp, dcf, loadtime
+page_cycles = 25
+page_timeout = 60000
+playback = mitmproxy
+playback_pageset_manifest = mitm4-linux-firefox-{subtest}.manifest
+playback_recordings = {subtest}.mp
+type = pageload
+unit = ms
+use_live_sites = false
+
+[amazon]
+test_url = https://www.amazon.com/s?k=laptop&ref=nb_sb_noss_1
+
+[bing-search]
+test_url = https://www.bing.com/search?q=barack+obama
+playback_recordings = bing.mp
+
+[facebook]
+test_url = https://www.facebook.com
+
+[google-search]
+test_url = https://www.google.com/search?hl=en&q=barack+obama&cad=h
+
+[google-slides]
+test_url = https://docs.google.com/presentation/d/1Ici0ceWwpFvmIb3EmKeWSq_vAQdmmdFcWqaiLqUkJng/edit?usp=sharing
+
+[wikipedia]
+test_url = https://en.wikipedia.org/wiki/Barack_Obama
+
+[yahoo-news]
+test_url = https://www.yahoo.com/lifestyle/police-respond-noise-complaint-end-playing-video-games-respectful-tenants-002329963.html
+
+[youtube]
+test_url = https://www.youtube.com

--- a/testing/raptor/raptor/utils.py
+++ b/testing/raptor/raptor/utils.py
@@ -44,16 +44,25 @@ def transform_platform(str_to_transform,
         if 'x86_64' in config_processor:
             str_to_transform = str_to_transform.replace('{x64}', '_x64')
         else:
             str_to_transform = str_to_transform.replace('{x64}', '')
 
     return str_to_transform
 
 
+def transform_subtest(str_to_transform, subtest_name):
+    """Transform subtest name i.e. 'mitm4-linux-firefox-{subtest}.manifest'
+    transforms to 'mitm4-linux-firefox-amazon.manifest'."""
+    if '{subtest}' not in str_to_transform:
+        return str_to_transform
+
+    return str_to_transform.replace('{subtest}', subtest_name)
+
+
 def view_gecko_profile(ffox_bin):
     # automatically load the latest talos gecko-profile archive in profiler.firefox.com
     LOG_GECKO = RaptorLogger(component='raptor-view-gecko-profile')
 
     if sys.platform.startswith('win') and not ffox_bin.endswith(".exe"):
         ffox_bin = ffox_bin + ".exe"
 
     if not os.path.exists(ffox_bin):

--- a/testing/raptor/test/conftest.py
+++ b/testing/raptor/test/conftest.py
@@ -85,17 +85,19 @@ def create_args():
                      test='raptor-tp6-unittest',
                      binary='path/to/binary',
                      gecko_profile=False,
                      debug_mode=False,
                      page_cycles=None,
                      page_timeout=None,
                      test_url_params=None,
                      host=None,
-                     run_local=True)
+                     run_local=True,
+                     browsertime=True,
+                     cold=False)
 
     def inner(**kwargs):
         for next_arg in kwargs:
             print(next_arg)
             print(kwargs[next_arg])
             setattr(args, next_arg, kwargs[next_arg])
         return args
 

--- a/testing/raptor/test/test_manifest.py
+++ b/testing/raptor/test/test_manifest.py
@@ -54,17 +54,16 @@ VALID_MANIFESTS = [{
     'alert_change_type': None,
     'alert_on': None,
     'playback': None,
 }, {
     # page load test for geckoview
     'alert_threshold': 2.0,
     'apps': 'geckoview',
     'browser_cycles': 10,
-    'cold': True,
     'lower_is_better': False,
     'manifest': 'valid_details_2',
     'measure': 'fcp',
     'page_cycles': 1,
     'test_url': 'http://www.test-url/goes/here',
     'type': 'pageload',
     'unit': 'score',
 }, {