While the current variant works, it assumes that all the instances of
a single family will be run together, with nothing inbetween them.
Naturally, that won't work once the runs may be interleaved.

Much like it makes sense to enumerate all the families,
it makes sense to enumerate stuff within families.
Alternatively, we could have a global instance index,
but i'm not sure why that would be better.

This will be useful when the benchmarks are run not in order,
for the tools to sort the results properly.

It may be useful for those wishing to further post-process JSON results,
but it is mainly geared towards better support for run interleaving,
where results from the same family may not be close-by in the JSON.

While we won't be able to do much about that for outputs,
the tools can and perhaps should reorder the results to that
at least in their output they are in proper order, not run order.

Note that this only counts the families that were filtered-in,
so if e.g. there were three families, and we filtered-out
the second one, the two families (which were first and third)
will have family indexes 0 and 1.

It takes the whole total new capacity, not the increase.

Ensure that we print repetition count even when it was specified via flag `--benchmark_repetitions=`

This reverts commit a6a738c1.

* Fix argument order in StrSplit

* Update AUTHORS, CONTRIBUTORS

It seems that by setting the /topic in freenode #googlebenchmark to point to libera I have angered the powers that be and we've been locked out of the channel. Libera it is then.

';' after method definition was removed.
Also, pedantic flag is now uncommented in CMakeList.txt.

* cmake: fix handling the case where `git describe` fails

* cmake: fix version recorded in releases

If downloaded as a tarball release, there will be no info from git
to determine the release, so it ends up v0.0.0. If that's the case,
we'll now use the release specified in the project() command,
which needs to be updated for each new release.

* cmake: add `--tags` to `git describe`

That way, lightweight tags will also be taken into account, which should
never hurt, but it'll help in cases where, for some mysterious reason or
other, annotated tags don't make it into a clone.

* update releasing.md

* Implementation of random interleaving. See
http://github.com/google/benchmark/issues/1051 for the feature requests.

Committer: Hai Huang (http://github.com/haih-g)

On branch fr-1051
Changes to be committed:
modified:   include/benchmark/benchmark.h
modified:   src/benchmark.cc
new file:   src/benchmark_adjust_repetitions.cc
new file:   src/benchmark_adjust_repetitions.h
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_api_internal.h
modified:   src/benchmark_register.cc
modified:   src/benchmark_runner.cc
modified:   src/benchmark_runner.h
modified:   test/CMakeLists.txt
new file:   test/benchmark_random_interleaving_gtest.cc

* Fix benchmark_random_interleaving_gtest.cc for fr-1051

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark.cc
modified:   src/benchmark_runner.cc
modified:   test/benchmark_random_interleaving_gtest.cc

* Fix macos build for fr-1051

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_api_internal.h
modified:   src/benchmark_runner.cc

* Fix macos and windows build for fr-1051.

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark_runner.cc

* Fix benchmark_random_interleaving_test.cc for macos and windows in fr-1051

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   test/benchmark_random_interleaving_gtest.cc

* Fix int type benchmark_random_interleaving_gtest for macos in fr-1051

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   test/benchmark_random_interleaving_gtest.cc

* Address dominichamon's comments 03/29 for fr-1051

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark.cc
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_api_internal.h
modified:   test/benchmark_random_interleaving_gtest.cc

* Address dominichamon's comment on default min_time / repetitions for fr-1051.
Also change sentinel of random_interleaving_repetitions to -1. Hopefully it
fixes the failures on Windows.

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark.cc
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_api_internal.h

* Fix windows test failures for fr-1051

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_runner.cc

* Add license blurb for fr-1051.

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark_adjust_repetitions.cc
modified:   src/benchmark_adjust_repetitions.h

* Switch to std::shuffle() for fr-1105.

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark.cc

* Change to 1e-9 in fr-1105

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark_adjust_repetitions.cc

* Fix broken build caused by bad merge for fr-1105.

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_runner.cc

* Fix build breakage for fr-1051.

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark.cc
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_api_internal.h
modified:   src/benchmark_register.cc
modified:   src/benchmark_runner.cc

* Print out reports as they come in if random interleaving is disabled (fr-1051)

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark.cc

* size_t, int64_t --> int in benchmark_runner for fr-1051.

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark_runner.cc
modified:   src/benchmark_runner.h

* Address comments from dominichamon for fr-1051

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark.cc
modified:   src/benchmark_adjust_repetitions.cc
modified:   src/benchmark_adjust_repetitions.h
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_api_internal.h
modified:   test/benchmark_random_interleaving_gtest.cc

* benchmar_indices --> size_t to make CI pass: fr-1051

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark.cc

* Fix min_time not initialized issue for fr-1051.

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_api_internal.h

* min_time --> MinTime in fr-1051.

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   src/benchmark_api_internal.cc
modified:   src/benchmark_api_internal.h
modified:   src/benchmark_runner.cc

* Add doc for random interleaving for fr-1051

Committer: Hai Huang <haih@google.com>

On branch fr-1051
Your branch is up to date with 'origin/fr-1051'.

Changes to be committed:
modified:   README.md
new file:   docs/random_interleaving.md
Co-authored-by: Dominic Hamon <dominichamon@users.noreply.github.com>

* Extend perf counter support to multi-threaded cases.

* Docs update

* const-ed Snapshot

* Support -Wsuggest-override

google/benchmark is C++11 compatible but doesn't use the `override` keyword.
Projects using google/benchmark with enabled `-Wsuggest-override` and `-Werror` will fail to compile.

* Add -Wsuggest-override cxx flag

* Revert unrelated formatting

* Revert unrelated formatting, take 2

* Revert unrelated formatting, take 3

* Disable -Wsuggest-override when compiling tests, gtest does not handle it yet
Co-authored-by: Dominic Hamon <dominichamon@users.noreply.github.com>

* Refactor BenchmarkInstance (precursor to #1105)

* fix bazel (debug) build

* clang-format on header

* fix build error on g++-4.8

* add g++-6 to ubuntu-14.04

* fix syntax

* fix yamllint errors for build-and-test

* fix 'add-apt-repository' command not found

* make 'run tests' explicit

* enable testing and run both release and debug

* oops

* Add ubuntu-14.04 build and test workflow

* avoid '.' in job name

* no need for fail fast

* fix workflow syntax

* install some stuff

* better compiler installations

* update before install

* just say yes

* trying to match up some paths

* Difference between runner and github context in container?

* Try some judicious logging

* cmake 3.5+ required

* specific compiler versions

* need git for googletest

* Disable testing on old compilers

* disable testing properly

This also fixes #1135. Because StrSplit was returning a vector with an
empty string, it was treated by PerfCounters::Create as a legitimate ask
for setting up a counter with that name. The empty vector is understood
by PerfCounters as "just return NoCounters()".

* Add API to benchmark allowing for custom context to be added

Fixes #525

* add docs

* Add context flag output to JSON reporter

* Plumb everything into the global context.

* Add googletests for custom context

* update docs with duplicate key behaviour

* Add `benchmark_context` flag that allows per-run custom context.

Add support for key-value flags in general.
Added test for key-value flags.
Added `benchmark_context` flag.
Output content of `benchmark_context` to base reporter.

Solves the first part of #525.

* Docs and better help

* Add 32-bit build support to build-and-test

* attempt different yaml multiline string format

* syntax fixes to yaml

* switch to getting alternative compilers working

* remove done TODO

* trying to separate out windows

* oops, typo.

* add TODOs for missing builds wrt travis

* Support optional, user-directed collection of performance counters

The patch allows an engineer wishing to drill into the root causes
of a regression, for example. Currently, only single threaded runs
are supported. The feature is a build-time opt in, and then a runtime
opt in.

The engineer may run the benchmark executable, passing a list of
performance counter names (using libpfm's naming scheme) at the
command line. The counter values will then be collected and reported
back as UserCounters.

This is different from #240 in that it is a benchmark user opt-in, and
the counter collection is transparent to the benchmark.

Currently, this is only supported on platforms where libpfm is
supported.

libpfm: http://perfmon2.sourceforge.net/

* 'Use' values param in Snapshot when BENCHMARK_OS_WINDOWS

This is to avoid unused parameter warning-as-error

* Added missing include for <vector> in perf_counters.cc

* Moved doc to docs

* Added license blurbs

Fixes #713

according to https://cmake.org/cmake/help/latest/command/function.html,
"Referencing to ARGV# arguments beyond ARGC have undefined behavior.",
which I hit with cmake 3.19.7.

This uses ARGC to check whether ARGV1 has been passed before referencing
it.

[tools] Fix dumb mistake in previous commit - print aggregates only means aggregates, not non-aggregates

This probably regressed in #1042.

Currently, i get:
```
Run on (32 X 7326.56 MHz CPU s)
CPU Caches:
  L1 Data 32 KiB (x16)
  L1 Instruction 32 KiB (x16)
  L2 Unified 512 KiB (x16)
  L3 Unified 32768 KiB (x2)
```
which seems mostly right, except that the frequency is rather bogus.
Yes, i guess the CPU could theoretically achieve that,
but i have 3.6GHz configured, and scaling disabled.
So we clearly read the wrong thing.

With this fix, i now get the expected
```
Run on (32 X 3598.53 MHz CPU s)
CPU Caches:
  L1 Data 32 KiB (x16)
  L1 Instruction 32 KiB (x16)
  L2 Unified 512 KiB (x16)
  L3 Unified 32768 KiB (x2)
```