Simple, fast, accurate microbenchmarking functionality for C++11/14/17/20
it could also make it easier to switch based on command line options, since if you reuse a same bench with a different title it will clear the current results ( and so you need to remember to call render before each call to title or a change in config)
so if I have something like:
int benchsIterations[] = {2, 8, 16, 32, 64, 256, 1024, 1024 * 1024};
for (int nbValues : benchsIterations)
{
cfg.title("Summation " + std::to_string(nbValues)).relative(true).minEpochIterations(50).minEpochTime(10ms);
nanobench::Rng rng;
std::vector<Scalar> values(nbValues);
std::generate(values.begin(), values.end(), [&] { return Scalar(rng.uniform01()); });
cfg.run("Naive raw sum", [&] {
const Scalar* beg = values.data();
Scalar acc = naive_sum(beg, beg + nbValues);
nanobench::doNotOptimizeAway(acc);
});
// More benchs
// I need to call render here, because if put out of the loop it will only render for the last loop
}
In version 4.0 I'll release some big changes to the rendering, then it will behave a bit differently. You still need to call render yourself though. You might want to create an issue for this though. Due to the corona lockdown I've practically no time for this so I would definitely forget without an issue
I saw this change
https://github.com/martinus/nanobench/commit/6f3b8f2adce0160d8e09f0802250bc80cf2e04b7#diff-6d37775f1ac5713cba7f653f48ed3b48L1987-L1996
Does this mean I should not be using the current master / mustache anymore ?
https://github.com/martinus/nanobench/commit/6f3b8f2adce0160d8e09f0802250bc80cf2e04b7#diff-6d37775f1ac5713cba7f653f48ed3b48L1987-L1996
Does this mean I should not be using the current master / mustache anymore ?
case Node::Type::tag:
- if (n == "unit") {
- out << bench.unit();
- } else if (n == "title") {
- out << bench.title();
- } else if (n == "batch") {
- out << bench.batch();
- } else {
- throw std::runtime_error("unknown tag '" + std::string(n.begin, n.end) + "'");
- }
+ throw std::runtime_error("unknown tag '" + std::string(n.begin, n.end) + "'");
break;
}
}
This seems a bit unpractical that
generate now takes only a std::vector<Result> and not Bench as param
Hi all! my plan is to update the documentation, potentially make a few small fixes, and then have a new release. @Lectem , you mentioned in onqtam/doctest#251 that you have a few changes to nanobench, do you plan/think it would be worthwhile to have these changes in nanobench? If so than I'd like to merge them into nanobench before updating the documentation. I don't want to rewrite it twice
I do have a few changes but they are not quite ready to be merged I think, but I'd love to discuss those with you
Basicly it's linked to reporters support, I hacked in a thing so that one can switch the reporter globally / replace the markdown one
The main objective was to be able to output json easily during CI
I also have a few other changes related to the iteration logic, they make it a bit longer to run but are IMHO more correct.
It +/- all boils down to the fact nanobench currently tries to reach not 1000x the clock resolution, but in fact only 2/3*1000
speaking of which, the comment says
and adds a 10% noise while it's a 20% noise :)
Good news, everyone! I've just released nanobench 4.0.0, which is a major update from 3.1.0. Lots of updates, and a new beautiful documentation: https://nanobench.ankerl.com/
btw, I was reading a bit about cpu counters, it seems that if you want accurate results on linux, you must have 4 enabled at most at the same time (for x64 CPUs), otherwise it's using multiplexing
which means you need the benchmark to last long enough otherwise results are interpolated
./external/nanobench/include\nanobench.h:444:19: error: couldn't allocate input reg for constraint 'r'
asm volatile("" : : "r"(val) : "memory");
^
looks like
asm volatile("" : : "r,m"(val) : "memory"); works though