* add Jordan Williams to both CONTRIBUTORS and AUTHORS
* alias benchmark libraries
Provide aliased CMake targets for the benchmark and benchmark_main targets.
The alias targets are namespaced under benchmark::, which is the namespace when they are exported.
I chose not to use either the PROJECT_NAME or the namespace variable but to hard-code the namespace.
This is because the benchmark and benchmark_main targets are hard-coded by name themselves.
Hard-coding the namespace is also much cleaner and easier to read.
* link to aliased benchmark targets
It is safer to link against namespaced targets because of how CMake interprets the double colon.
Typo's will be caught by CMake at configuration-time instead of during compile / link time.
* document the provided alias targets
* add "Usage with CMake" section in documentation
This section covers linking against the alias/import CMake targets and including them using either find_package or add_subdirectory.
* format the "Usage with CMake" README section
Added a newline after the "Usage with CMake" section header.
Dropped the header level of the section by one to make it a direct subsection of the "Usage" section.
Wrapped lines to be no longer than 80 characters in length.
* Update with instructions to build under Visual Studio
Fixes Issue #634.
I spent 3 days trying to build this library under Visual Studio 2017, only to discover on has to link to `Shlwapi.lib`.
Became so frustrated with the docs that I added full build instructions for Visual Studio 2015, 2017 and Intel Comiler 2015 and 2019.
* Update headings
While current counters can e.g. answer the question
"how many items is processed per second", it is impossible to get
it to tell "how many seconds it takes to process a single item".
The solution is to add a yet another modifier `kInvert`,
that is *always* considered last, which simply inverts the answer.
Fixes#781, #830, #848.
* Counter(): add 'one thousand' param.
Needed for https://github.com/google/benchmark/pull/654
Custom user counters are quite custom. It is not guaranteed
that the user *always* expects for these to have 1k == 1000.
If the counter represents bytes/memory/etc, 1k should be 1024.
Some bikeshedding points:
1. Is this sufficient, or do we really want to go full on
into custom types with names?
I think just the '1000' is sufficient for now.
2. Should there be a helper benchmark::Counter::Counter{1000,1024}()
static 'constructor' functions, since these two, by far,
will be the most used?
3. In the future, we should be somehow encoding this info into JSON.
* Counter(): use std::pair<> to represent 'one thousand'
* Counter(): just use a new enum with two values 1000 vs 1024.
Simpler is better. If someone comes up with a real reason
to need something more advanced, it can be added later on.
* Counter: just store the 1000 or 1024 in the One_K values directly
* Counter: s/One_K/OneK/
* Add benchmark_main library with support for Bazel.
* fix newline at end of file
* Add CMake support for benchmark_main.
* Mention optionally using benchmark_main in README.
* Correct/clarify build/install instructions
GTest is google test, don't obsfucate needlessly for newcomers.
Adding google test into installation guide helps newcomers.
Third option under this line: "Note that Google Benchmark requires Google Test to build and run the tests. This
dependency can be provided three ways:"
Was not true (did not occur). If there is a further option that needs to be specified in order for that functionality to work it needs to be specified.
* Add prerequisite knowledge section
A lot of assumptions are made about the reader in the documentation. This is unfortunate.
* Removal of abbreviations for google test
Note, bazel only supports MSVC on Windows, and not MinGW, so
linking against shlwapi.lib only needs to follow MSVC conventions.
git_repository() did not work in local testing, so is swapped for
http_archive(). The latter is also documented as the preferred way
to depend on an external library in bazel.
* Add tests to verify assembler output -- Fix DoNotOptimize.
For things like `DoNotOptimize`, `ClobberMemory`, and even `KeepRunning()`,
it is important exactly what assembly they generate. However, we currently
have no way to test this. Instead it must be manually validated every
time a change occurs -- including a change in compiler version.
This patch attempts to introduce a way to test the assembled output automatically.
It's mirrors how LLVM verifies compiler output, and it uses LLVM FileCheck to run
the tests in a similar way.
The tests function by generating the assembly for a test in CMake, and then
using FileCheck to verify the // CHECK lines in the source file are found
in the generated assembly.
Currently, the tests only run on 64-bit x86 systems under GCC and Clang,
and when FileCheck is found on the system.
Additionally, this patch tries to improve the code gen from DoNotOptimize.
This should probably be a separate change, but I needed something to test.
* Disable assembly tests on Bazel for now
* Link FIXME to github issue
* Fix Tests on OS X
* fix strip_asm.py to work on both Linux and OS X like targets
* Add Solaris support
Define BENCHMARK_OS_SOLARIS for Solaris.
Platform specific implementations added:
* number of CPUs detection
* CPU cycles per second detection
* Thread CPU usage
* Process CPU usage
* Remove the special case for per process CPU time for Solaris, it's the same as the default.
For people who get this library via CMake's AddExternalProject like me.
Would like a long term tutorial from someone who really understands CMake on how to actually link an externalproject's dependencies to another added external project.
* Add support for GTest based unit tests.
As Dominic and I have previously discussed, there is some
need/desire to improve the testing situation in Google Benchmark.
One step to fixing this problem is to make it easier to write
unit tests by adding support for GTest, which is what this patch does.
By default it looks for an installed version of GTest. However the
user can specify -DBENCHMARK_BUILD_EXTERNAL_GTEST=ON to instead
download, build, and use copy of gtest from source. This is
quite useful when Benchmark is being built in non-standard configurations,
such as against libc++ or in 32 bit mode.
This patch documents the newly added v2 branch, which will
be used to stage, test, and receive feedback on upcoming
features, most of which will be breaking changes which can't
be directly applied to master.
Describe how to use the cpupower command to disable CPU frequency scaling.
Document this, since there are other ways that don't see to have the same
effect. See #325
* Fix BM_SetInsert example
Move declaration of `std::set<int> data` outside the timing loop, so that the
destructor is not timed.
* Speed up BM_SetInsert test
Since the time taken to ConstructRandomSet() is so large compared to the time
to insert one element, but only the latter is used to determine number of
iterations, this benchmark now takes an extremely long time to run in
benchmark_test.
Speed it up two ways:
- Increase the Ranges() parameters
- Cache ConstructRandomSet() result (it's not random anyway), and do only
O(N) copy every iteration
* Fix same issue in BM_MapLookup test
* Make BM_SetInsert test consistent with README
- Use the same Ranges everywhere, but increase the 2nd range
- Change order of Args() calls in README to more closely match the result of Ranges
- Don't cache ConstructRandomSet, since it doesn't make sense in README
- Get a smaller optimization inside it, by givint a hint to insert()
Recently the library added a new ranged-for variant of the KeepRunning
loop that is much faster. For this reason it should be preferred in all
new code.
Because a library, its documentation, and its tests should all embody
the best practices of using the library, this patch changes all but a
few usages of KeepRunning() into for (auto _ : state).
The remaining usages in the tests and documentation persist only
to document and test behavior that is different between the two formulations.
Also note that because the range-for loop requires C++11, the KeepRunning
variant has not been deprecated at this time.
* Add C++11 Ranged For loop alternative to KeepRunning
As pointed out by @astrelni and @dominichamon, the KeepRunning
loop requires a bunch of memory loads and stores every iterations,
which affects the measurements.
The main reason for these additional loads and stores is that the
State object is passed in by reference, making its contents externally
visible memory, and the compiler doesn't know it hasn't been changed
by non-visible code.
It's also possible the large size of the State struct is hindering
optimizations.
This patch allows the `State` object to be iterated over using
a range-based for loop. Example:
void BM_Foo(benchmark::State& state) {
for (auto _ : state) {
[...]
}
}
This formulation is much more efficient, because the variable counting
the loop index is stored in the iterator produced by `State::begin()`,
which itself is stored in function-local memory and therefore not accessible
by code outside of the function. Therefore the compiler knows the iterator
hasn't been changed every iteration.
This initial patch and idea was from Alex Strelnikov.
* Fix null pointer initialization in C++03
* Fix#444 - Use BENCHMARK_HAS_CXX11 over __cplusplus.
MSVC incorrectly defines __cplusplus to report C++03, despite the compiler
actually providing C++11 or greater. Therefore we have to detect C++11 differently
for MSVC. This patch uses `_MSVC_LANG` which has been defined since
Visual Studio 2015 Update 3; which should be sufficient for detecting C++11.
Secondly this patch changes over most usages of __cplusplus >= 201103L to
check BENCHMARK_HAS_CXX11 instead.
* remove redunant comment
