upstream/mercurial-mirror Files · contrib/fuzz/fuzzutil.cc

match: improve includematcher.visitchildrenset to be much faster and cached...

match: improve includematcher.visitchildrenset to be much faster and cached This improves the speed of visitchildrenset considerably, especially when there are complicated matchers involved that may have many entries in _dirs or _parents. Unfortunately the benchmark isn't easily upstreamed due to its reliance on https://github.com/vstinner/perf (primarily due to the conflict when importing it if I were to contribute the benchmark as contrib/matcherbenchmarks.py) instead of asv or some other perf measurement system. To describe the benchmark briefly: I generated an includematcher of either 5 or 3500 "rootfilesin:prefix1/prefix2/prefix3/<randomsubdirs, 1-8 levels deep>" items in the 'setup' function, and then called `im.visitchildrenset('prefix1/prefix2')` in the 'stmt' function in perf.timeit. For the set of 5: - before: 15.3 us +- 2.9 us - after: 1.59 us +- 0.02 us For the set of 3500: - before: 3.90 ms +- 0.10 ms - after: 3.15 us +- 0.09 us (note the m->u change) Differential Revision: https://phab.mercurial-scm.org/D4351

Yuya Nishihara - - Load All Authors

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      #include "fuzzutil.h"

      #include <cstring>

      #include <utility>

      contrib::optional<two_inputs> SplitInputs(const uint8_t *Data, size_t Size)

      {

      	if (!Size) {

      		return contrib::nullopt;

      	}

      	// figure out a random point in [0, Size] to split our input.

      	size_t left_size = (Data[0] / 255.0) * (Size - 1);

      	// Copy inputs to new allocations so if bdiff over-reads

      	// AddressSanitizer can detect it.

      	std::unique_ptr<char[]> left(new char[left_size]);

      	std::memcpy(left.get(), Data + 1, left_size);

      	// right starts at the next byte after left ends

      	size_t right_size = Size - (left_size + 1);

      	std::unique_ptr<char[]> right(new char[right_size]);

      	std::memcpy(right.get(), Data + 1 + left_size, right_size);

      	LOG(2) << "inputs are  " << left_size << " and " << right_size

      	       << " bytes" << std::endl;

      	two_inputs result = {std::move(right), right_size, std::move(left),

      	                     left_size};

      	return result;

      }

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				#include "fuzzutil.h"

				#include <cstring>
				#include <utility>

				contrib::optional<two_inputs> SplitInputs(const uint8_t *Data, size_t Size)
				{
				if (!Size) {
				return contrib::nullopt;
				}
				// figure out a random point in [0, Size] to split our input.
				size_t left_size = (Data[0] / 255.0) * (Size - 1);

				// Copy inputs to new allocations so if bdiff over-reads
				// AddressSanitizer can detect it.
				std::unique_ptr<char[]> left(new char[left_size]);
				std::memcpy(left.get(), Data + 1, left_size);
				// right starts at the next byte after left ends
				size_t right_size = Size - (left_size + 1);
				std::unique_ptr<char[]> right(new char[right_size]);
				std::memcpy(right.get(), Data + 1 + left_size, right_size);
				LOG(2) << "inputs are " << left_size << " and " << right_size
				<< " bytes" << std::endl;
				two_inputs result = {std::move(right), right_size, std::move(left),
				left_size};
				return result;
				}