Re: the experimental jit-branch is impressive

From:	lists@rhsoft.net	Date:	Tue, 02 May 2017 19:51:08 +0000
Subject:	Re: the experimental jit-branch is impressive
References:	1 2 3 4 5 6 7	Groups:	php.internals
Request:	Send a blank email to internals+get-98944@lists.php.net to get a copy of this message

Am 02.05.2017 um 21:12 schrieb Nikita Popov:

On Tue, May 2, 2017 at 9:04 PM, lists@rhsoft.net
You have xdebug enabled...
    loaded, but not enabled
    xdebug.default_enable = 0
    xdebug.profiler_enable = 0
    xdebug.profiler_enable_trigger = 1
    7.1.5:             Requests per second: 136.46
    7.1.5 opcache:     Requests per second: 316.77
    7.2.0 JIT PGO:     Requests per second: 925.96
    7.2.0 JIT NON-PGO: Requests per second: 849.99
    around 8% are the difference with or without PGO, no idea how much
    strict-types and a 100% typehinted codebase makes a difference to
    the JIT operations
This is a common misconception. If you have loaded xdebug you will incur a major performance hit, regardless of ini settings. xdebug.default_enable is a badly named option, which controls display of stack traces, not whether xdebug is enabled. As far as I know, there is no way to disable xdebug once it has been loaded. Please unload xdebug and try again

argh - when the trigger is set to generate profiling files runtime is doubled compared with xdebug just loaded but indeed xdebug has a massive impact

7.1.5 PGO:     Requests per second: 886.63

7.2.0 JIT PGO: Requests per second: 925.96 OK, than it are "only" 5% on a highly optimized codebase interesting is the impact of PGO-profiling which has likely a code-coverage nearly to 95% and that without xdebug our cms-system seems to be that efficient that it nearly runs as fast on a quad-core i7 from 2011 than on a 12-core Xeon from 2015.....