Ori Livneh 47f0194c2a Avoid calling into PHP from Lua to check if 'current' or 'empty' frames exist ... On the Wikimedia cluster, 1.6% of MediaWiki wall-clock time is burnt on calls from Lua into Scribunto_LuaSandboxCallback::frameExists()[1]. We can optimize away many of these calls by not calling into PHP to check if 'empty' or 'current' exist: the engine always reports that the 'empty' frame exists, and 'current' is guaranteed to have been set up (in LuaEngine::setupCurrentFrames) prior to calling into Lua. To help validate this, I added debug logging to the current production branch of Scribunto[2] to see if there are any cases where Scribunto_LuaSandboxCallback::frameExists('current') is false. As I write this commit message, the logging code has been active for 24H and there have not been any occurrences. [1]: https://performance.wikimedia.org/arclamp/svgs/daily/2021-03-16.excimer-wall.all.reversed.svgz [2]: https://gerrit.wikimedia.org/r/c/mediawiki/extensions/Scribunto/+/672836 Change-Id: I1902b711c9a442a5a42745a582a6a9ff988a355f		2021-03-17 18:04:09 -07:00
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LuaCommon	Avoid calling into PHP from Lua to check if 'current' or 'empty' frames exist	2021-03-17 18:04:09 -07:00
LuaSandbox	Add missing @var and improve documentation	2020-12-22 01:15:00 +00:00
LuaStandalone	Add missing @var and improve documentation	2020-12-22 01:15:00 +00:00