Merge lp:~vanvugt/mir/ClientLatency-of-overlays into lp:mir

[Daniel van Vugt]

Add a new ClientLatency acceptance test showing how bypass/overlays
actually make latency one frame lower.

Admittedly this is kind of the test testing itself, but it's instructive
anyway.

This was another one of the discoveries to come out of 'mirvanity'.
It does raise an interesting issue though -- if the latency of an
overlay triple-buffered surface is one frame, then that means there's only
one frame of pre-rendering and it doesn't have the smoothness guarantees
that triple buffering usually provides. It's actually only guaranteed the
smoothness of double-buffering (unless you allocate quad buffers).

[Mir CI Bot (mir-ci-bot)]

FAILED: Continuous integration, rev:3449
https://mir-jenkins.ubuntu.com/job/mir-ci/796/
Executed test runs:
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-mir/791/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/828
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=vivid+overlay/819
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=xenial/819
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=vivid+overlay/800/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/800
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/800/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=android,release=vivid+overlay/800/console
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=android,release=vivid+overlay/800/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/800
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/800/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/800
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/800/artifact/output/*zip*/output.zip

Click here to trigger a rebuild:
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review: Needs Fixing (continuous-integration)

[Mir CI Bot (mir-ci-bot)]

FAILED: Continuous integration, rev:3450
https://mir-jenkins.ubuntu.com/job/mir-ci/800/
Executed test runs:
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-mir/795/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/832
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=vivid+overlay/823
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=xenial/823
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=vivid+overlay/804
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=vivid+overlay/804/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/804
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/804/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=android,release=vivid+overlay/804/console
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=android,release=vivid+overlay/804/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/804
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/804/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/804
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/804/artifact/output/*zip*/output.zip

Click here to trigger a rebuild:
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review: Needs Fixing (continuous-integration)

[Daniel van Vugt (vanvugt)]

^ The krillin failure is bug 1556045 again.

[lp:~vanvugt/mir/ClientLatency-of-overlays]

3451. By Daniel van Vugt on 2016-04-11

No change

[Mir CI Bot (mir-ci-bot)]

FAILED: Continuous integration, rev:3451
https://mir-jenkins.ubuntu.com/job/mir-ci/801/
Executed test runs:
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-mir/796/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/833
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=vivid+overlay/824
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=xenial/824
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=vivid+overlay/805
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=vivid+overlay/805/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/805
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/805/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=android,release=vivid+overlay/805/console
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=android,release=vivid+overlay/805/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/805
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/805/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/805
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/805/artifact/output/*zip*/output.zip

Click here to trigger a rebuild:
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review: Needs Fixing (continuous-integration)

[lp:~vanvugt/mir/ClientLatency-of-overlays]

3452. By Daniel van Vugt on 2016-04-12

Merge latest trunk

[Mir CI Bot (mir-ci-bot)]

FAILED: Continuous integration, rev:3452
https://mir-jenkins.ubuntu.com/job/mir-ci/812/
Executed test runs:
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-mir/813/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/850
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=vivid+overlay/841
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=xenial/841
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=vivid+overlay/823
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=vivid+overlay/823/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/823
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/823/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=android,release=vivid+overlay/823/console
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=android,release=vivid+overlay/823/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/823
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/823/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/823
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/823/artifact/output/*zip*/output.zip

Click here to trigger a rebuild:
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review: Needs Fixing (continuous-integration)

[Daniel van Vugt (vanvugt)]

Sigh. krillin in CI is apparently too slow to pass that new test. But it wasn't too important...

Unmerged revisions

3452. By Daniel van Vugt on 2016-04-12

Merge latest trunk

3451. By Daniel van Vugt on 2016-04-11

No change

3450. By Daniel van Vugt on 2016-04-11

Use a struct instead of bitfield

3449. By Daniel van Vugt on 2016-04-08

Better comment

3448. By Daniel van Vugt on 2016-04-08

Enable overlay simulation. Now the test passes.

3447. By Daniel van Vugt on 2016-04-08

Add overlays test. Presently fails.

=== modified file 'tests/acceptance-tests/test_latency.cpp'
--- tests/acceptance-tests/test_latency.cpp	2016-04-11 16:56:16 +0000
+++ tests/acceptance-tests/test_latency.cpp	2016-04-12 04:59:57 +0000
@@ -32,7 +32,7 @@
 #include <gtest/gtest.h>
 #include <gmock/gmock.h>
 #include <deque>
-
+#include <atomic>
 #include <mutex>
 #include <condition_variable>
 
@@ -116,6 +116,12 @@
     };
     std::deque<Submission> submissions;
 };
+
+struct Options
+{
+    std::atomic_bool simulate_overlays{false};
+};
+
 /*
  * Note: we're not aiming to check performance in terms of CPU or GPU time processing
  * the incoming buffers. Rather, we're checking that we don't have any intrinsic
@@ -124,6 +130,8 @@
 class IdCollectingDB : public mtd::NullDisplayBuffer
 {
 public:
+    IdCollectingDB(Options const& opt) : options{opt} {}
+
     mir::geometry::Rectangle view_area() const override
     {
         return {{0,0}, {1920, 1080}};
@@ -131,24 +139,43 @@
 
     bool post_renderables_if_optimizable(mg::RenderableList const& renderables) override
     {
+        if (options.simulate_overlays)
+            prev_onscreen = next_onscreen;
+
         //the surface will be the frontmost of the renderables
         if (!renderables.empty())
-            last = renderables.front()->buffer()->id();
+        {
+            auto buffer = renderables.front()->buffer();
+            the_last_id = buffer->id();
+            if (options.simulate_overlays)
+                next_onscreen = buffer;
+        }
 
         return true;
     }
+
+    void swap_completed()
+    {
+        prev_onscreen.reset();
+    }
+
     mg::BufferID last_id()
     {
-        return last;
+        return the_last_id;
     }
 private:
-    mg::BufferID last{0};
+    Options const& options;
+    mg::BufferID the_last_id{0};
+    std::shared_ptr<mg::Buffer> next_onscreen, prev_onscreen;
 };
 
 class TimeTrackingGroup : public mtd::NullDisplaySyncGroup
 {
 public:
-    TimeTrackingGroup(Stats& stats) : stats{stats} {}
+    TimeTrackingGroup(Stats& stats, Options const& opt)
+        : stats{stats}, db(opt)
+    {
+    }
 
     void for_each_display_buffer(std::function<void(mg::DisplayBuffer&)> const& f) override
     {
@@ -175,6 +202,7 @@
          * latency would never exceed 1.0.  (LP: #1447947)
          */
         std::this_thread::sleep_for(vblank_interval);
+        db.swap_completed();
     }
 
     float average_latency()
@@ -224,8 +252,8 @@
 
 struct TimeTrackingDisplay : mtd::NullDisplay
 {
-    TimeTrackingDisplay(Stats& stats)
-        : group{stats}
+    TimeTrackingDisplay(Stats& stats, Options const& opt)
+        : group(stats, opt)
     {
     }
 
@@ -240,6 +268,7 @@
 {
     void SetUp() override
     {
+        options.simulate_overlays = false;
         preset_display(mt::fake_shared(display));
         mtf::ConnectedClientHeadlessServer::SetUp();
 
@@ -259,7 +288,8 @@
     }
 
     Stats stats;
-    TimeTrackingDisplay display{stats};
+    Options options;
+    TimeTrackingDisplay display{stats, options};
     unsigned int test_submissions{100};
 
     // We still have a margin for error here. The client and server will
@@ -296,6 +326,39 @@
     EXPECT_THAT(observed_latency, Lt(expected_max_latency+error_margin));
 }
 
+/*
+ * Overlays/bypass wasn't ever expected to reduce latency, but a quirk of
+ * the algorithm means it does. When you have a buffer overlayed on screen,
+ * you need to hold it till after you have guaranteed that it's been replaced
+ * and definitely not on screen any more. This means the compositor holds
+ * an overlay/bypass buffer for one frame longer than it would for GL.
+ */
+TEST_F(ClientLatency, overlayed_client_has_latency_nbuffers_minus_2)
+{
+    using namespace testing;
+
+    options.simulate_overlays = true;
+
+    auto stream = mir_surface_get_buffer_stream(surface);
+    for(auto i = 0u; i < test_submissions; i++) {
+        auto submission_id = mir_debug_surface_current_buffer_id(surface);
+        stats.record_submission(submission_id);
+        mir_buffer_stream_swap_buffers_sync(stream);
+    }
+
+    ASSERT_TRUE(stats.wait_for_posts(test_submissions,
+                                     std::chrono::seconds(60)));
+
+    float const expected_max_latency = expected_client_buffers - 2;
+
+    if (server.get_options()->get<bool>(mtd::logging_opt))
+        display.group.dump_latency();
+
+    auto observed_latency = display.group.average_latency();
+
+    EXPECT_THAT(observed_latency, Lt(expected_max_latency+error_margin));
+}
+
 TEST_F(ClientLatency, latency_is_limited_to_nbuffers)
 {
     using namespace testing;