diff --git a/init/README.md b/init/README.md
index f48fa6b..120d293 100644
--- a/init/README.md
+++ b/init/README.md
@@ -174,6 +174,17 @@
 be executed. The condition `boot && property:true=true` will be evaluated to
 false because the `boot` trigger is a past event.
 
+Note that when `ro.property_service.async_persist_writes` is `true`, there is no
+defined ordering between persistent setprops and non-persistent setprops. For
+example:
+
+    on boot
+        setprop a 1
+        setprop persist.b 2
+
+When `ro.property_service.async_persist_writes` is `true`, triggers for these
+two properties may execute in any order.
+
 Services
 --------
 Services are programs which init launches and (optionally) restarts
diff --git a/init/property_service.cpp b/init/property_service.cpp
index 9df9828..87ffdb9 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -98,6 +98,9 @@
 
 namespace android {
 namespace init {
+
+class PersistWriteThread;
+
 constexpr auto FINGERPRINT_PROP = "ro.build.fingerprint";
 constexpr auto LEGACY_FINGERPRINT_PROP = "ro.build.legacy.fingerprint";
 constexpr auto ID_PROP = "ro.build.id";
@@ -115,6 +118,8 @@
 static std::mutex accept_messages_lock;
 static std::thread property_service_thread;
 
+static std::unique_ptr<PersistWriteThread> persist_write_thread;
+
 static PropertyInfoAreaFile property_info_area;
 
 struct PropertyAuditData {
@@ -177,48 +182,13 @@
     return has_access;
 }
 
-static uint32_t PropertySet(const std::string& name, const std::string& value, std::string* error) {
-    size_t valuelen = value.size();
-
-    if (!IsLegalPropertyName(name)) {
-        *error = "Illegal property name";
-        return PROP_ERROR_INVALID_NAME;
-    }
-
-    if (auto result = IsLegalPropertyValue(name, value); !result.ok()) {
-        *error = result.error().message();
-        return PROP_ERROR_INVALID_VALUE;
-    }
-
-    prop_info* pi = (prop_info*) __system_property_find(name.c_str());
-    if (pi != nullptr) {
-        // ro.* properties are actually "write-once".
-        if (StartsWith(name, "ro.")) {
-            *error = "Read-only property was already set";
-            return PROP_ERROR_READ_ONLY_PROPERTY;
-        }
-
-        __system_property_update(pi, value.c_str(), valuelen);
-    } else {
-        int rc = __system_property_add(name.c_str(), name.size(), value.c_str(), valuelen);
-        if (rc < 0) {
-            *error = "__system_property_add failed";
-            return PROP_ERROR_SET_FAILED;
-        }
-    }
-
-    // Don't write properties to disk until after we have read all default
-    // properties to prevent them from being overwritten by default values.
-    if (persistent_properties_loaded && StartsWith(name, "persist.")) {
-        WritePersistentProperty(name, value);
-    }
+void NotifyPropertyChange(const std::string& name, const std::string& value) {
     // If init hasn't started its main loop, then it won't be handling property changed messages
     // anyway, so there's no need to try to send them.
     auto lock = std::lock_guard{accept_messages_lock};
     if (accept_messages) {
         PropertyChanged(name, value);
     }
-    return PROP_SUCCESS;
 }
 
 class AsyncRestorecon {
@@ -259,7 +229,9 @@
 
 class SocketConnection {
   public:
+    SocketConnection() = default;
     SocketConnection(int socket, const ucred& cred) : socket_(socket), cred_(cred) {}
+    SocketConnection(SocketConnection&&) = default;
 
     bool RecvUint32(uint32_t* value, uint32_t* timeout_ms) {
         return RecvFully(value, sizeof(*value), timeout_ms);
@@ -318,6 +290,8 @@
 
     const ucred& cred() { return cred_; }
 
+    SocketConnection& operator=(SocketConnection&&) = default;
+
   private:
     bool PollIn(uint32_t* timeout_ms) {
         struct pollfd ufd = {
@@ -388,9 +362,78 @@
     unique_fd socket_;
     ucred cred_;
 
-    DISALLOW_IMPLICIT_CONSTRUCTORS(SocketConnection);
+    DISALLOW_COPY_AND_ASSIGN(SocketConnection);
 };
 
+class PersistWriteThread {
+  public:
+    PersistWriteThread();
+    void Write(std::string name, std::string value, SocketConnection socket);
+
+  private:
+    void Work();
+
+  private:
+    std::thread thread_;
+    std::mutex mutex_;
+    std::condition_variable cv_;
+    std::deque<std::tuple<std::string, std::string, SocketConnection>> work_;
+};
+
+static std::optional<uint32_t> PropertySet(const std::string& name, const std::string& value,
+                                           SocketConnection* socket, std::string* error) {
+    size_t valuelen = value.size();
+
+    if (!IsLegalPropertyName(name)) {
+        *error = "Illegal property name";
+        return {PROP_ERROR_INVALID_NAME};
+    }
+
+    if (auto result = IsLegalPropertyValue(name, value); !result.ok()) {
+        *error = result.error().message();
+        return {PROP_ERROR_INVALID_VALUE};
+    }
+
+    prop_info* pi = (prop_info*)__system_property_find(name.c_str());
+    if (pi != nullptr) {
+        // ro.* properties are actually "write-once".
+        if (StartsWith(name, "ro.")) {
+            *error = "Read-only property was already set";
+            return {PROP_ERROR_READ_ONLY_PROPERTY};
+        }
+
+        __system_property_update(pi, value.c_str(), valuelen);
+    } else {
+        int rc = __system_property_add(name.c_str(), name.size(), value.c_str(), valuelen);
+        if (rc < 0) {
+            *error = "__system_property_add failed";
+            return {PROP_ERROR_SET_FAILED};
+        }
+    }
+
+    // Don't write properties to disk until after we have read all default
+    // properties to prevent them from being overwritten by default values.
+    if (socket && persistent_properties_loaded && StartsWith(name, "persist.")) {
+        if (persist_write_thread) {
+            persist_write_thread->Write(name, value, std::move(*socket));
+            return {};
+        }
+        WritePersistentProperty(name, value);
+    }
+
+    NotifyPropertyChange(name, value);
+    return {PROP_SUCCESS};
+}
+
+// Helper for PropertySet, for the case where no socket is used, and therefore an asynchronous
+// return is not possible.
+static uint32_t PropertySetNoSocket(const std::string& name, const std::string& value,
+                                    std::string* error) {
+    auto ret = PropertySet(name, value, nullptr, error);
+    CHECK(ret.has_value());
+    return *ret;
+}
+
 static uint32_t SendControlMessage(const std::string& msg, const std::string& name, pid_t pid,
                                    SocketConnection* socket, std::string* error) {
     auto lock = std::lock_guard{accept_messages_lock};
@@ -481,16 +524,17 @@
     return PROP_SUCCESS;
 }
 
-// This returns one of the enum of PROP_SUCCESS or PROP_ERROR*.
-uint32_t HandlePropertySet(const std::string& name, const std::string& value,
-                           const std::string& source_context, const ucred& cr,
-                           SocketConnection* socket, std::string* error) {
+// This returns one of the enum of PROP_SUCCESS or PROP_ERROR*, or std::nullopt
+// if asynchronous.
+std::optional<uint32_t> HandlePropertySet(const std::string& name, const std::string& value,
+                                          const std::string& source_context, const ucred& cr,
+                                          SocketConnection* socket, std::string* error) {
     if (auto ret = CheckPermissions(name, value, source_context, cr, error); ret != PROP_SUCCESS) {
-        return ret;
+        return {ret};
     }
 
     if (StartsWith(name, "ctl.")) {
-        return SendControlMessage(name.c_str() + 4, value, cr.pid, socket, error);
+        return {SendControlMessage(name.c_str() + 4, value, cr.pid, socket, error)};
     }
 
     // sys.powerctl is a special property that is used to make the device reboot.  We want to log
@@ -511,7 +555,7 @@
         }
         if (value == "reboot,userspace" && !is_userspace_reboot_supported().value_or(false)) {
             *error = "Userspace reboot is not supported by this device";
-            return PROP_ERROR_INVALID_VALUE;
+            return {PROP_ERROR_INVALID_VALUE};
         }
     }
 
@@ -522,10 +566,20 @@
     if (name == kRestoreconProperty && cr.pid != 1 && !value.empty()) {
         static AsyncRestorecon async_restorecon;
         async_restorecon.TriggerRestorecon(value);
-        return PROP_SUCCESS;
+        return {PROP_SUCCESS};
     }
 
-    return PropertySet(name, value, error);
+    return PropertySet(name, value, socket, error);
+}
+
+// Helper for HandlePropertySet, for the case where no socket is used, and
+// therefore an asynchronous return is not possible.
+uint32_t HandlePropertySetNoSocket(const std::string& name, const std::string& value,
+                                   const std::string& source_context, const ucred& cr,
+                                   std::string* error) {
+    auto ret = HandlePropertySet(name, value, source_context, cr, nullptr, error);
+    CHECK(ret.has_value());
+    return *ret;
 }
 
 static void handle_property_set_fd() {
@@ -576,8 +630,7 @@
 
         const auto& cr = socket.cred();
         std::string error;
-        uint32_t result =
-                HandlePropertySet(prop_name, prop_value, source_context, cr, nullptr, &error);
+        auto result = HandlePropertySetNoSocket(prop_name, prop_value, source_context, cr, &error);
         if (result != PROP_SUCCESS) {
             LOG(ERROR) << "Unable to set property '" << prop_name << "' from uid:" << cr.uid
                        << " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
@@ -603,14 +656,19 @@
             return;
         }
 
+        // HandlePropertySet takes ownership of the socket if the set is handled asynchronously.
         const auto& cr = socket.cred();
         std::string error;
-        uint32_t result = HandlePropertySet(name, value, source_context, cr, &socket, &error);
-        if (result != PROP_SUCCESS) {
+        auto result = HandlePropertySet(name, value, source_context, cr, &socket, &error);
+        if (!result) {
+            // Result will be sent after completion.
+            return;
+        }
+        if (*result != PROP_SUCCESS) {
             LOG(ERROR) << "Unable to set property '" << name << "' from uid:" << cr.uid
                        << " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
         }
-        socket.SendUint32(result);
+        socket.SendUint32(*result);
         break;
       }
 
@@ -622,10 +680,9 @@
 }
 
 uint32_t InitPropertySet(const std::string& name, const std::string& value) {
-    uint32_t result = 0;
     ucred cr = {.pid = 1, .uid = 0, .gid = 0};
     std::string error;
-    result = HandlePropertySet(name, value, kInitContext, cr, nullptr, &error);
+    auto result = HandlePropertySetNoSocket(name, value, kInitContext, cr, &error);
     if (result != PROP_SUCCESS) {
         LOG(ERROR) << "Init cannot set '" << name << "' to '" << value << "': " << error;
     }
@@ -795,7 +852,7 @@
         load_properties_from_file("/data/local.prop", nullptr, &properties);
         for (const auto& [name, value] : properties) {
             std::string error;
-            if (PropertySet(name, value, &error) != PROP_SUCCESS) {
+            if (PropertySetNoSocket(name, value, &error) != PROP_SUCCESS) {
                 LOG(ERROR) << "Could not set '" << name << "' to '" << value
                            << "' in /data/local.prop: " << error;
             }
@@ -861,7 +918,7 @@
                 LOG(INFO) << "Setting product property " << base_prop << " to '" << target_prop_val
                           << "' (from " << target_prop << ")";
                 std::string error;
-                uint32_t res = PropertySet(base_prop, target_prop_val, &error);
+                auto res = PropertySetNoSocket(base_prop, target_prop_val, &error);
                 if (res != PROP_SUCCESS) {
                     LOG(ERROR) << "Error setting product property " << base_prop << ": err=" << res
                                << " (" << error << ")";
@@ -890,7 +947,7 @@
     }
 
     std::string error;
-    auto res = PropertySet(ID_PROP, build_id, &error);
+    auto res = PropertySetNoSocket(ID_PROP, build_id, &error);
     if (res != PROP_SUCCESS) {
         LOG(ERROR) << "Failed to set " << ID_PROP << " to " << build_id;
     }
@@ -938,7 +995,7 @@
               << legacy_build_fingerprint << "'";
 
     std::string error;
-    uint32_t res = PropertySet(LEGACY_FINGERPRINT_PROP, legacy_build_fingerprint, &error);
+    auto res = PropertySetNoSocket(LEGACY_FINGERPRINT_PROP, legacy_build_fingerprint, &error);
     if (res != PROP_SUCCESS) {
         LOG(ERROR) << "Error setting property '" << LEGACY_FINGERPRINT_PROP << "': err=" << res
                    << " (" << error << ")";
@@ -956,7 +1013,7 @@
     LOG(INFO) << "Setting property '" << FINGERPRINT_PROP << "' to '" << build_fingerprint << "'";
 
     std::string error;
-    uint32_t res = PropertySet(FINGERPRINT_PROP, build_fingerprint, &error);
+    auto res = PropertySetNoSocket(FINGERPRINT_PROP, build_fingerprint, &error);
     if (res != PROP_SUCCESS) {
         LOG(ERROR) << "Error setting property '" << FINGERPRINT_PROP << "': err=" << res << " ("
                    << error << ")";
@@ -1018,7 +1075,7 @@
         LOG(INFO) << "Setting property '" << prop << "' to '" << prop_val << "'";
 
         std::string error;
-        uint32_t res = PropertySet(prop, prop_val, &error);
+        auto res = PropertySetNoSocket(prop, prop_val, &error);
         if (res != PROP_SUCCESS) {
             LOG(ERROR) << "Error setting property '" << prop << "': err=" << res << " (" << error
                        << ")";
@@ -1052,7 +1109,7 @@
     int api_level = std::min(read_api_level_props(BOARD_API_LEVEL_PROPS),
                              read_api_level_props(DEVICE_API_LEVEL_PROPS));
     std::string error;
-    uint32_t res = PropertySet(VENDOR_API_LEVEL_PROP, std::to_string(api_level), &error);
+    auto res = PropertySetNoSocket(VENDOR_API_LEVEL_PROP, std::to_string(api_level), &error);
     if (res != PROP_SUCCESS) {
         LOG(ERROR) << "Failed to set " << VENDOR_API_LEVEL_PROP << " with " << api_level << ": "
                    << error << "(" << res << ")";
@@ -1146,7 +1203,7 @@
 
     for (const auto& [name, value] : properties) {
         std::string error;
-        if (PropertySet(name, value, &error) != PROP_SUCCESS) {
+        if (PropertySetNoSocket(name, value, &error) != PROP_SUCCESS) {
             LOG(ERROR) << "Could not set '" << name << "' to '" << value
                        << "' while loading .prop files" << error;
         }
@@ -1388,6 +1445,46 @@
     }
 }
 
+PersistWriteThread::PersistWriteThread() {
+    auto new_thread = std::thread([this]() -> void { Work(); });
+    thread_.swap(new_thread);
+}
+
+void PersistWriteThread::Work() {
+    while (true) {
+        std::tuple<std::string, std::string, SocketConnection> item;
+
+        // Grab the next item within the lock.
+        {
+            std::unique_lock<std::mutex> lock(mutex_);
+
+            while (work_.empty()) {
+                cv_.wait(lock);
+            }
+
+            item = std::move(work_.front());
+            work_.pop_front();
+        }
+
+        std::this_thread::sleep_for(1s);
+
+        // Perform write/fsync outside the lock.
+        WritePersistentProperty(std::get<0>(item), std::get<1>(item));
+        NotifyPropertyChange(std::get<0>(item), std::get<1>(item));
+
+        SocketConnection& socket = std::get<2>(item);
+        socket.SendUint32(PROP_SUCCESS);
+    }
+}
+
+void PersistWriteThread::Write(std::string name, std::string value, SocketConnection socket) {
+    {
+        std::unique_lock<std::mutex> lock(mutex_);
+        work_.emplace_back(std::move(name), std::move(value), std::move(socket));
+    }
+    cv_.notify_all();
+}
+
 void StartPropertyService(int* epoll_socket) {
     InitPropertySet("ro.property_service.version", "2");
 
@@ -1412,6 +1509,13 @@
 
     auto new_thread = std::thread{PropertyServiceThread};
     property_service_thread.swap(new_thread);
+
+    auto async_persist_writes =
+            android::base::GetBoolProperty("ro.property_service.async_persist_writes", false);
+
+    if (async_persist_writes) {
+        persist_write_thread = std::make_unique<PersistWriteThread>();
+    }
 }
 
 }  // namespace init
diff --git a/init/property_service.h b/init/property_service.h
index 2d49a36..71a609c 100644
--- a/init/property_service.h
+++ b/init/property_service.h
@@ -18,7 +18,11 @@
 
 #include <sys/socket.h>
 
+#include <condition_variable>
+#include <deque>
+#include <mutex>
 #include <string>
+#include <thread>
 
 #include "epoll.h"