| #
162e1dce |
| 09-Jan-2024 |
Tim Düsterhus |
random: Optimize data flow for the `generate` function of native engines (#13043)
Instead of returning the generated `uint64_t` and providing the size (i.e. the
number of bytes of the ge
random: Optimize data flow for the `generate` function of native engines (#13043)
Instead of returning the generated `uint64_t` and providing the size (i.e. the
number of bytes of the generated value) out-of-band via the
`last_generated_size` member of the `php_random_status` struct, the `generate`
function is now expected to return a new `php_random_result` struct containing
both the `size` and the `result`.
This has two benefits, one for the developer:
It's no longer possible to forget setting `last_generated_size` to the correct
value, because it now happens at the time of returning from the function.
and the other benefit is for performance:
The `php_random_result` struct will be returned as a register pair, thus the
`size` will be directly available without reloading it from main memory.
Checking a simplified version of `php_random_range64()` on Compiler Explorer
(“Godbolt”) with clang 17 shows a single change in the resulting assembly
showcasing the improvement (https://godbolt.org/z/G4WjdYxqx):
- add rbp, qword ptr [r14]
+ add rbp, rdx
Empirical testing confirms a measurable performance increase for the
`Randomizer::getBytes()` method:
<?php
$e = new Random\Engine\Xoshiro256StarStar(0);
$r = new Random\Randomizer($e);
var_dump(strlen($r->getBytes(100000000)));
goes from 250ms (before the change) to 220ms (after the change). While
generating 100 MB of random data certainly is not the most common use case, it
confirms the theoretical improvement in practice.
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|
| #
3331832b |
| 02-Aug-2022 |
Tim Düsterhus |
Add ext/random Exception hierarchy (#9220)
* Add Random\Random{Error,Exception} and Random\BrokenRandomEngineError
* Throw BrokenRandomEngineError
* Throw RandomException o
Add ext/random Exception hierarchy (#9220)
* Add Random\Random{Error,Exception} and Random\BrokenRandomEngineError
* Throw BrokenRandomEngineError
* Throw RandomException on seeding failure
* Throw RandomException when CSPRNG fails
* Remove unused include from ext/random/engine_combinedlcg.c
* Remove unused include from ext/random/engine_secure.c
* Remove unused include from ext/random/random.c
* [ci skip] Add ext/random Exception hierarchy to NEWS
* [ci skip] Add the change of Exception for random_(int|bytes) to UPGRADING
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