diff --git a/tools/jenkins/run_jenkins_matrix.sh b/tools/jenkins/run_jenkins_matrix.sh
new file mode 100755
index 0000000000000000000000000000000000000000..b3783e69584a166e997fa9b1a07357f6b1e28930
--- /dev/null
+++ b/tools/jenkins/run_jenkins_matrix.sh
@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# This script is invoked by Jenkins and triggers a test run, bypassing
+# all args to the test script.
+#
+# Setting up rvm environment BEFORE we set -ex.
+[[ -s /etc/profile.d/rvm.sh ]] && . /etc/profile.d/rvm.sh
+# To prevent cygwin bash complaining about empty lines ending with \r
+# we set the igncr option. The option doesn't exist on Linux, so we fallback
+# to just 'set -ex' there.
+# NOTE: No empty lines should appear in this file before igncr is set!
+set -ex -o igncr || set -ex
+
+python tools/run_tests/run_tests_matrix.py $@
diff --git a/tools/run_tests/dockerize/build_docker_and_run_tests.sh b/tools/run_tests/dockerize/build_docker_and_run_tests.sh
index c2ea6f2c6eb05b37c06c959aa85a5b400d430af6..b4b172ddef63827725d54a8d641052ecc886c35e 100755
--- a/tools/run_tests/dockerize/build_docker_and_run_tests.sh
+++ b/tools/run_tests/dockerize/build_docker_and_run_tests.sh
@@ -44,9 +44,6 @@ mkdir -p /tmp/ccache
 # its cache location now that --download-cache is deprecated).
 mkdir -p /tmp/xdg-cache-home
 
-# Create a local branch so the child Docker script won't complain
-git branch -f jenkins-docker
-
 # Inputs
 # DOCKERFILE_DIR - Directory in which Dockerfile file is located.
 # DOCKER_RUN_SCRIPT - Script to run under docker (relative to grpc repo root)
@@ -86,9 +83,12 @@ docker run \
   $DOCKER_IMAGE_NAME \
   bash -l "/var/local/jenkins/grpc/$DOCKER_RUN_SCRIPT" || DOCKER_FAILED="true"
 
-docker cp "$CONTAINER_NAME:/var/local/git/grpc/reports.zip" $git_root || true
-unzip -o $git_root/reports.zip -d $git_root || true
-rm -f reports.zip
+# use unique name for reports.zip to prevent clash between concurrent
+# run_tests.py runs 
+TEMP_REPORTS_ZIP=`mktemp`
+docker cp "$CONTAINER_NAME:/var/local/git/grpc/reports.zip" ${TEMP_REPORTS_ZIP} || true
+unzip -o ${TEMP_REPORTS_ZIP} -d $git_root || true
+rm -f ${TEMP_REPORTS_ZIP}
 
 # remove the container, possibly killing it first
 docker rm -f $CONTAINER_NAME || true
diff --git a/tools/run_tests/dockerize/docker_run_tests.sh b/tools/run_tests/dockerize/docker_run_tests.sh
index 8c6143d24f97802dc2cf5b7596596b5497a5a922..ef02d266253751c7a4189f524ee0eca9e6a9c628 100755
--- a/tools/run_tests/dockerize/docker_run_tests.sh
+++ b/tools/run_tests/dockerize/docker_run_tests.sh
@@ -63,6 +63,7 @@ echo '</body></html>' >> index.html
 cd ..
 
 zip -r reports.zip reports
-find . -name report.xml | xargs zip reports.zip
+find . -name report.xml | xargs -r zip reports.zip
+find . -name 'report_*.xml' | xargs -r zip reports.zip
 
 exit $exit_code
diff --git a/tools/run_tests/run_tests_in_workspace.sh b/tools/run_tests/run_tests_in_workspace.sh
new file mode 100755
index 0000000000000000000000000000000000000000..98ef3566db1a031ab95a5429d1b8d42b5a6a4855
--- /dev/null
+++ b/tools/run_tests/run_tests_in_workspace.sh
@@ -0,0 +1,46 @@
+#!/bin/bash
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# Create a workspace in a subdirectory to allow running multiple builds in isolation.
+# WORKSPACE_NAME env variable needs to contain name of the workspace to create.
+# All cmdline args will be passed to run_tests.py script (executed in the 
+# newly created workspace)
+set -ex
+
+cd $(dirname $0)/../..
+
+rm -rf "${WORKSPACE_NAME}"
+# TODO(jtattermusch): clone --recursive fetches the submodules from github.
+# Try avoiding that to save time and network capacity.
+git clone --recursive . "${WORKSPACE_NAME}"
+
+echo "Running run_tests.py in workspace ${WORKSPACE_NAME}" 
+python "${WORKSPACE_NAME}/tools/run_tests/run_tests.py" $@
+
diff --git a/tools/run_tests/run_tests_matrix.py b/tools/run_tests/run_tests_matrix.py
new file mode 100755
index 0000000000000000000000000000000000000000..a94f9cfef5e1ed777b09e64cbf93b47941c9ee2b
--- /dev/null
+++ b/tools/run_tests/run_tests_matrix.py
@@ -0,0 +1,282 @@
+#!/usr/bin/env python2.7
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Run test matrix."""
+
+import argparse
+import jobset
+import multiprocessing
+import os
+import report_utils
+import sys
+
+_ROOT = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), '../..'))
+os.chdir(_ROOT)
+
+# Set the timeout high to allow enough time for sanitizers and pre-building
+# clang docker.
+_RUNTESTS_TIMEOUT = 2*60*60
+
+# Number of jobs assigned to each run_tests.py instance
+_INNER_JOBS = 2
+
+
+def _docker_jobspec(name, runtests_args=[]):
+  """Run a single instance of run_tests.py in a docker container"""
+  test_job = jobset.JobSpec(
+          cmdline=['python', 'tools/run_tests/run_tests.py',
+                   '--use_docker',
+                   '-t',
+                   '-j', str(_INNER_JOBS),
+                   '-x', 'report_%s.xml' % name] + runtests_args,
+          shortname='run_tests_%s' % name,
+          timeout_seconds=_RUNTESTS_TIMEOUT)
+  return test_job
+
+
+def _workspace_jobspec(name, runtests_args=[], workspace_name=None):
+  """Run a single instance of run_tests.py in a separate workspace"""
+  if not workspace_name:
+    workspace_name = 'workspace_%s' % name
+  env = {'WORKSPACE_NAME': workspace_name}
+  test_job = jobset.JobSpec(
+          cmdline=['tools/run_tests/run_tests_in_workspace.sh',
+                   '-t',
+                   '-j', str(_INNER_JOBS),
+                   '-x', '../report_%s.xml' % name] + runtests_args,
+          environ=env,
+          shortname='run_tests_%s' % name,
+          timeout_seconds=_RUNTESTS_TIMEOUT)
+  return test_job
+
+
+def _generate_jobs(languages, configs, platforms,
+                  arch=None, compiler=None,
+                  labels=[], extra_args=[]):
+  result = []
+  for language in languages:
+    for platform in platforms:
+      for config in configs:
+        name = '%s_%s_%s' % (language, platform, config)
+        runtests_args = ['-l', language,
+                         '-c', config]
+        if arch or compiler:
+          name += '_%s_%s' % (arch, compiler)
+          runtests_args += ['--arch', arch,
+                            '--compiler', compiler]
+
+        runtests_args += extra_args
+        if platform == 'linux':
+          job = _docker_jobspec(name=name, runtests_args=runtests_args)
+        else:
+          job = _workspace_jobspec(name=name, runtests_args=runtests_args)
+
+        job.labels = [platform, config, language] + labels
+        result.append(job)
+  return result
+
+
+def _create_test_jobs(extra_args=[]):
+  test_jobs = []
+  # supported on linux only
+  test_jobs += _generate_jobs(languages=['sanity', 'php7'],
+                             configs=['dbg', 'opt'],
+                             platforms=['linux'],
+                             labels=['basictests'],
+                             extra_args=extra_args)
+  
+  # supported on all platforms.
+  test_jobs += _generate_jobs(languages=['c', 'csharp', 'node', 'python'],
+                             configs=['dbg', 'opt'],
+                             platforms=['linux', 'macos', 'windows'],
+                             labels=['basictests'],
+                             extra_args=extra_args)
+  
+  # supported on linux and mac.
+  test_jobs += _generate_jobs(languages=['c++', 'ruby', 'php'],
+                              configs=['dbg', 'opt'],
+                              platforms=['linux', 'macos'],
+                              labels=['basictests'],
+                              extra_args=extra_args)
+  
+  # supported on mac only.
+  test_jobs += _generate_jobs(languages=['objc'],
+                              configs=['dbg', 'opt'],
+                              platforms=['macos'],
+                              labels=['basictests'],
+                              extra_args=extra_args)
+  
+  # sanitizers
+  test_jobs += _generate_jobs(languages=['c'],
+                              configs=['msan', 'asan', 'tsan'],
+                              platforms=['linux'],
+                              labels=['sanitizers'],
+                              extra_args=extra_args)
+  test_jobs += _generate_jobs(languages=['c++'],
+                              configs=['asan', 'tsan'],
+                              platforms=['linux'],
+                              labels=['sanitizers'],
+                              extra_args=extra_args)
+  return test_jobs
+
+  
+def _create_portability_test_jobs(extra_args=[]):
+  test_jobs = []
+  # portability C x86
+  test_jobs += _generate_jobs(languages=['c'],
+                              configs=['dbg'],
+                              platforms=['linux'],
+                              arch='x86',
+                              compiler='default',
+                              labels=['portability'],
+                              extra_args=extra_args)
+  
+  # portability C and C++ on x64
+  for compiler in ['gcc4.4', 'gcc4.6', 'gcc5.3',
+                   'clang3.5', 'clang3.6', 'clang3.7']:
+    test_jobs += _generate_jobs(languages=['c', 'c++'],
+                                configs=['dbg'],
+                                platforms=['linux'],
+                                arch='x64',
+                                compiler=compiler,
+                                labels=['portability'],
+                                extra_args=extra_args)
+  
+  # portability C on Windows
+  for arch in ['x86', 'x64']:
+    for compiler in ['vs2013', 'vs2015']:
+      test_jobs += _generate_jobs(languages=['c'],
+                                  configs=['dbg'],
+                                  platforms=['windows'],
+                                  arch=arch,
+                                  compiler=compiler,
+                                  labels=['portability'],
+                                  extra_args=extra_args)
+  
+  test_jobs += _generate_jobs(languages=['python'],
+                              configs=['dbg'],
+                              platforms=['linux'],
+                              arch='default',
+                              compiler='python3.4',
+                              labels=['portability'],
+                              extra_args=extra_args)
+  
+  test_jobs += _generate_jobs(languages=['csharp'],
+                              configs=['dbg'],
+                              platforms=['linux'],
+                              arch='default',
+                              compiler='coreclr',
+                              labels=['portability'],
+                              extra_args=extra_args)
+  return test_jobs  
+
+
+def _allowed_labels():
+  """Returns a list of existing job labels."""
+  all_labels = set()
+  for job in _create_test_jobs() + _create_portability_test_jobs():
+    for label in job.labels:
+      all_labels.add(label)
+  return sorted(all_labels)
+
+
+argp = argparse.ArgumentParser(description='Run a matrix of run_tests.py tests.')
+argp.add_argument('-j', '--jobs',
+                  default=multiprocessing.cpu_count()/_INNER_JOBS,
+                  type=int,
+                  help='Number of concurrent run_tests.py instances.')
+argp.add_argument('-f', '--filter',
+                  choices=_allowed_labels(),
+                  nargs='+',
+                  default=[],
+                  help='Filter targets to run by label with AND semantics.')
+argp.add_argument('--build_only',
+                  default=False,
+                  action='store_const',
+                  const=True,
+                  help='Pass --build_only flag to run_tests.py instances.')
+argp.add_argument('--force_default_poller', default=False, action='store_const', const=True,
+                  help='Pass --force_default_poller to run_tests.py instances.')
+argp.add_argument('--dry_run',
+                  default=False,
+                  action='store_const',
+                  const=True,
+                  help='Only print what would be run.')
+args = argp.parse_args()
+
+extra_args = []
+if args.build_only:
+  extra_args.append('--build_only')
+if args.force_default_poller:
+  extra_args.append('--force_default_poller')
+
+all_jobs = _create_test_jobs(extra_args=extra_args) + _create_portability_test_jobs(extra_args=extra_args)
+
+jobs = []
+for job in all_jobs:
+  if not args.filter or all(filter in job.labels for filter in args.filter):
+    jobs.append(job)
+
+if not jobs:
+  jobset.message('FAILED', 'No test suites match given criteria.',
+                 do_newline=True)
+  sys.exit(1)
+  
+print('IMPORTANT: The changes you are testing need to be locally committed')
+print('because only the committed changes in the current branch will be')
+print('copied to the docker environment or into subworkspaces.')
+
+print 
+print 'Will run these tests:'
+for job in jobs:
+  if args.dry_run:
+    print '  %s: "%s"' % (job.shortname, ' '.join(job.cmdline))
+  else:
+    print '  %s' % job.shortname
+print
+
+if args.dry_run:
+  print '--dry_run was used, exiting'
+  sys.exit(1)
+
+jobset.message('START', 'Running test matrix.', do_newline=True)
+num_failures, resultset = jobset.run(jobs,
+                                     newline_on_success=True,
+                                     travis=True,
+                                     maxjobs=args.jobs)
+report_utils.render_junit_xml_report(resultset, 'report.xml')
+
+if num_failures == 0:
+  jobset.message('SUCCESS', 'All run_tests.py instance finished successfully.',
+                 do_newline=True)
+else:
+  jobset.message('FAILED', 'Some run_tests.py instance have failed.',
+                 do_newline=True)
+  sys.exit(1)