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author | Wladimir J. van der Laan <laanwj@gmail.com> | 2018-03-01 12:12:55 +0100 |
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committer | Wladimir J. van der Laan <laanwj@gmail.com> | 2018-03-01 12:13:08 +0100 |
commit | 32987d5aebc4e0fb757ad77dc727e5d7ee9d394b (patch) | |
tree | c40fa26e4d0350f6609b3557030c800ea9921631 /src/compat.h | |
parent | 9e2ed253f50500e1db4927d511d3ac0d47aed8df (diff) | |
parent | 5aad635b78c8359adae9b2af015b67b7325c0e0b (diff) |
Merge #12549: Make prevector::resize() and other prevector operations much faster
5aad635 Use memset() to optimize prevector::resize() (Evan Klitzke)
e46be25 Reduce redundant code of prevector and speed it up (Akio Nakamura)
f0e7aa7 Add new prevector benchmarks. (Evan Klitzke)
Pull request description:
This branch optimizes various `prevector` operations, especially resizing vectors. While profiling the `loadblk` thread I noticed that a lot of time was being spent in `prevector::resize()` which led to this work. I have some data here indicating that it takes up **37%** of the time in `ReadBlockFromDisk()`: https://monad.io/readblockfromdisk.svg
This branch improves things significantly. For trivial types, the new results for the prevector benchmark are:
* `PrevectorClearTrivial` which tests `prevector::clear()` becomes 24.6x faster
* `PrevectorDestructorTrivial` which tests `prevector::~prevector()` becomes 20.5x faster
* `PrevectorResizeTrivial` which tests `prevector::resize()` becomes 20.3x faster
Note that in practice it looks like the prevector is only used to contain `unsigned char` types, which is a trivial type. The benchmarks are testing a bit of an extreme case, but the changes here are motivated by the profiling data for `ReadBlockFromDisk()` I linked to above.
The pull request here consists of a series of three commits:
* The first adds new benchmarks but does not change the prevector code.
* The second is from @AkioNak , and merges some prevector optimizations he submitted in #11988
* The third optimizes `prevector::resize()` to use `memset()` when the prevector contains trivially constructible types
Tree-SHA512: 28f7cbb91a19f9f43b6a5942781d7eb2e3197389186b666f086b69df12bee37773140f765426d715bfb8ebff79cb27a5f1206d0325b54b4aa65598b50fb18368
Diffstat (limited to 'src/compat.h')
-rw-r--r-- | src/compat.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/compat.h b/src/compat.h index aae84b1181..8a0f901304 100644 --- a/src/compat.h +++ b/src/compat.h @@ -10,6 +10,16 @@ #include <config/bitcoin-config.h> #endif +#include <type_traits> + +// GCC 4.8 is missing some C++11 type_traits, +// https://www.gnu.org/software/gcc/gcc-5/changes.html +#if defined(__GNUC__) && __GNUC__ < 5 +#define IS_TRIVIALLY_CONSTRUCTIBLE std::is_trivial +#else +#define IS_TRIVIALLY_CONSTRUCTIBLE std::is_trivially_constructible +#endif + #ifdef WIN32 #ifdef _WIN32_WINNT #undef _WIN32_WINNT |