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diff --git a/devtools/docs/tests/performance-tests.md b/devtools/docs/tests/performance-tests.md new file mode 100644 index 0000000000..01ecd18b92 --- /dev/null +++ b/devtools/docs/tests/performance-tests.md @@ -0,0 +1,192 @@ +# Performance Tests: DAMP + +DAMP (DevTools At Maximum Performance) is our test suite to track performance. + +## How to run it locally? + +```bash +./mach talos-test --activeTests damp +``` +Note that the first run is slower as it pulls a large tarball with various website copies. +This will run all DAMP tests, you can filter by test name with: +```bash +./mach talos-test --activeTests damp --subtests console +``` +This command will run all tests which contains "console" in their name. + +### Command line options + +#### Running tests only once + +```bash +./mach talos-test --activeTests damp --cycles 1 --tppagecycles 1 +``` +`--cycles` will limit the number of Firefox restart to only one, while +`--tppagecycles` will limit the number of test re-run in each firefox start to one. +This is often helpful when debugging one particular subtest. + +#### Taking screenshots + +```bash +DEBUG_DEVTOOLS_SCREENSHOTS=1 ./mach talos-test --activeTests damp +``` +When passing `DEBUG_DEVTOOLS_SCREENSHOTS` env variable, screenshots will be taken after each subtest +was run. The screenshot will be opened in new tabs and their title +includes the subtest label. Firefox won't automatically close so that you can view the screenshots. + +#### Recording a profile + +```bash +./mach talos-test --activeTests damp --gecko-profile --gecko-profile-entries 100000000 +``` +This will automatically record the tests and open the profile. You may use the following command in order +to focus on just one subtest run: +```bash +./mach talos-test --activeTests damp --subtests custom.webconsole --cycles 1 --tppagecycles 1 --gecko-profile --gecko-profile-entries 100000000 +``` + +## How to run it on try? + +```bash +./mach try fuzzy --query "'linux64-shippable/ 'damp" --rebuild 6 +``` +* Linux appears to build and run quickly, and offers quite stable results over the other OSes. +The vast majority of performance issues for DevTools are OS agnostic, so it doesn't really matter which one you run them on. +* "damp" is the talos bucket in which we run DAMP. +* And 6 is the number of times we run DAMP tests. That's to do averages between all the 6 runs and helps filtering out the noise. + +## How to get performance profiles on try? + +Once you have a successful try job for `damp`: +* select this job in treeherder +* click on the `...` menu in the bottom left +* select "Create Gecko Profile" + + + +This should start a new damp job called `damp-p`. Once `damp-p` is finished: +* select the `damp-p` job +* click on `Job Details` tab +* click on `open in Firefox Profiler` + +## What does it do? + +DAMP measures three important operations: +* Open a toolbox +* Reload the web page +* Close the toolbox +It measures the time it takes to do each of these operations for the following panels: + +inspector, console, netmonitor debugger, memory, performance. + +It runs all these three tests two times. Each time against a different web page: +* "simple": an empty webpage. This test highlights the performance of all tools against the simplest possible page. +* "complicated": a copy of bild.de website. This is supposed to represent a typical website to debug via DevTools. + +Then, there are a couple of extra tests: +* "cold": we run the three operations (open toolbox, page reload and close toolbox) first with the inspector. +This is run first after Firefox's startup, before any other test. +This test allows to measure a "cold startup". When a user first interacts with DevTools, many resources are loaded and cached, +so that all next interactions will be significantly faster. +* and many other smaller tests, focused on one particular feature or possible slowness for each panel. + +## How to see the results from try? + +First, open TreeHerder. A link is displayed in your console when executing `./mach try`. +You should also receive a mail with a link to it. + +Look for "T-e10s(+6)", click on "+6", then click on "damp": + + +On the bottom panel that just opened, click on "Compare result against another revision". + + +You are now on PerfHerder, click on "Compare", + + +Next to "Talos" select menu, in the filter textbox, type "damp". +Under "damp opt e10s" item, mouse over the "linux64" line, click on "subtests" link. + + +And here you get the results for each DAMP test: + + +On this page, you can filter by test name with the filter box on top of the result table. +This table has the following columns: +* Base: + Average time it took to run the test on the base build (by default, the last 2 days of DAMP runs on mozilla-central revisions) +* New: + Average time it took to run the test on the new build, the one with your patches. + Both "Base" and "New" have a "± x.xx%" suffix which tells you the variance of the timings. + i.e. the average difference in percent between the median timing and both the slowest and the fastest. +* Delta: + Difference in percent between the base and new runs. + The color of this can be red, orange or green: + * Red means "certainly regressing" + * Orange means "possibly regressing" + * Green means "certainly improving" + * No colored background means "nothing to conclude" + The difference between certainly and possibly is explained by the next column. +* Confidence: + If there is a significant difference between the two runs, tells if the results is trustworthy. + * "low" either means there isn't a significant difference between the two runs, or the difference is smaller than the typical variance of the given test. + If the test is known to have an execution time varying by 2% between two runs of the same build, and you get a 1% difference between your base and new builds, + the confidence will be low. You really can't make any conclusion. + * "med" means medium confidence and the delta is around the size of the variance. It may highlight a regression, but it can still be justified by the test noise. + * "high" means that this is a high confidence difference. The delta is significantly higher than the typical test variance. A regression is most likely detected. + +There is also "Show only important changes" checkbox, which helps seeing if there is any significant regression. +It will only display regressions and improvements with a medium or high confidence. + +## How to contribute to DAMP? + +DAMP is based on top of a more generic test suite called [Talos](https://wiki.mozilla.org/Buildbot/Talos). +Talos is a Mozilla test suite to follow all Firefox components performance. +It is written in Python and here are [the sources](https://searchfox.org/mozilla-central/source/testing/talos/) in mozilla-central. +Compared to the other test suites, it isn't run on the cloud, but on dedicated hardware. +This is to ensure performance numbers are stable over time and between two runs. +Talos runs various types of tests. More specifically, DAMP is a [Page loader test](https://wiki.mozilla.org/Buildbot/Talos/Tests#Page_Load_Tests). +The [source code](http://searchfox.org/mozilla-central/source/testing/talos/talos/tests/devtools/) for DAMP is also in mozilla-central. +See [Writing new performance test](./writing-perf-tests.md) for more information about the implementation of DAMP tests. + +## How to see the performance trends? + +You can find the dedicated performance dashboard for DevTools at http://firefox-dev.tools/performance-dashboard. You will find links to trend charts for various tools: +* [Inspector dashboard](http://firefox-dev.tools/performance-dashboard/tools/inspector.html?days=60&filterstddev=true) +* [Console dashboard](http://firefox-dev.tools/performance-dashboard/tools/console.html?days=60&filterstddev=true) +* [Netmonitor dashboard](http://firefox-dev.tools/performance-dashboard/tools/netmonitor.html?days=60&filterstddev=true) +* [Debugger dashboard](http://firefox-dev.tools/performance-dashboard/tools/debugger.html?days=60&filterstddev=true) + +Each tool page displays charts for all the subtests relevant for a given panel. + +Each circle on the chart is a push to mozilla-central. You can hover on a circle to see some additional information about the push, such as the date, the performance impact for the subtest, and the push id. Clicking on a circle will take you to the pushlog. + +Colored circles indicate that the push contains a change that was identified as having a performance impact. Those can be categorized as: +- hardware: hardware change for the machines used to run Talos +- platform: non-DevTools change that impacts DevTools performance +- damp: test change in DAMP that impacts test results +- devtools: identified DevTools change that introduced an improvement or regression + +This data is synchronized from a [shared Google doc](https://docs.google.com/spreadsheets/d/12Goo3vq-0X0_Ay-J6gfV56pUB8GC0Nl62I4p8G-UsEA/edit#gid=0). + +There is a PerfHerder link on each chart that will take you to the PerfHerder page corresponding to this subtest. + +## How to use PerfHerder charts + +On PerfHerder charts, each circle is a push on mozilla-central. +When you see a spike or a drop, you can try to identify the patch that relates to it by clicking the circles. +It will show a black popup. Then click on the changeset hash like "cb717386aec8" and you will get a mercurial changelog. +Then it is up to you to read the changelog and see which changeset may have hit the performance. + +For example, open [this page](https://treeherder.mozilla.org/perf.html#/graphs?timerange=31536000&series=mozilla-central,1417969,1,1&series=mozilla-central,1417971,1,1&series=mozilla-central,1417966,1,1&highlightedRevisions=a06f92099a5d&zoom=1482734645161.3916,1483610598216.4773,594.756508587898,969.2883437938906). +This is tracking inspector opening performance against the "Simple" page. + + +See the regression on Dec 31th? +Now, click on the first yellow circle of this spike. +You will get a black popup like this one: + + +Click on the [changelog link](https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=9104708cc3ac0ccfe4cf5d518e13736773c565d7&tochange=a06f92099a5d8edeb05e5971967fe8d6cd4c593c) to see which changesets were added during this run. Here, you will see that the regression comes from these patches: + * Bug 1245921 - Turn toolbox toolbar into a React component + * Bug 1245921 - Monkey patch ReactDOM event system for XUL |