This directory houses performance benchmark tests for the Shared Storage API.
See the Shared Storage API Explainer for more details about the API itself.
This assumes you are in the root directory of a local chromium checkout.
Select one of the available shared storage benchmarks, where the qualifier describes the size of the database after setup and prior to the test:
shared_storage.freshshared_storage.smallshared_storage.mediumshared_storage.largeRun the following bash command in your Chromium source directory to see a list of available browser types on your machine:
tools/perf/run_benchmark --browser=list
Sample output from the above command where four available types are found:
Available browsers:
desktop
content-shell-default
default
stable
system
Select a browser type from the list, e.g. system, which refers to your system's default installation of Chrome.
Run the following bash command in your Chromium source directory, substituting in your chosen benchmark and browser type:
tools/perf/run_benchmark shared_storage.small --browser=system
Alternatively you can omit the browser type in the command if you select browser type default:
tools/perf/run_benchmark shared_storage.small
Note that the default browser type is only available if you have a compiled build in a Chromium out directory named “Default”. (The latest compiled build will be used.)
Similarly, you can make release and debug browser types available by having compiled release and debug builds in Chromium out directories named “Release” and “Debug”, respectively.
Another alternative to selecting browser type is to pass your build directory via --chromium-output-directory, as long as you have named your out directory as one of the recognized out directories “Default”, “Release”, “Release_x64”, “Debug”, or “Debug_x64”.
For example, the following command uses the debug browser type, or in other words the most recent build in $CHROMIUM_SRC/out/Default, where $CHROMIUM_SRC is your Chromium source directory:
tools/perf/run_benchmark shared_storage.small --chromium-output-directory=out/Debug
Optionally, you can qualify your command further as follows:
--story-filter=STORY_FILTER Only use stories whose names match the given filter regexp.--iterations=ITERATIONS Override the default number of action iterations per story with the given number. Default is 10. Maximum allowed is 10.--pageset-repeat=PAGESET_REPEAT Number of times to repeat the entire story set. Default is 10.--xvfb Runs tests with Xvfb server if possible.--verbose-cpu-metrics Enables non-UMA CPU metrics.--verbose-memory-metrics Enables non-UMA memory metrics.-v, --verbose Increase verbosity level (repeat as needed).More options can be found by running:
tools/perf/run_benchmark run --help
For example, a modified version of the benchmark command is:
tools/perf/run_benchmark shared_storage.small --chromium-output-directory=out/Debug --story-filter=Append --iterations=5 --pageset-repeat=1 --xvfb --verbose-cpu-metrics --verbose-memory-metrics --verbose
By default, shared storage perf test results will be displayed in a file at path $CHROMIUM_SRC/tools/perf/results.html, where $CHROMIUM_SRC is your Chromium source directory.
The shared storage perf tests have a script to process results further into various human-friendly files with paths $CHROMIUM_SRC/tools/perf/contrib/shared_storage/data/histograms_*.json.
To run the script, run the following command manually after a perf test run completes:
tools/perf/contrib/shared_storage/process_results
In particular, the above script will compare the actual histogram sample counts recorded during the run with the expected counts, and notify you of any deltas. If there are any non-zero deltas.