https://bugs.freedesktop.org/show_bug.cgi?id=51787
Bug #: 51787 Summary: performance regression with llvm shader compiler in ut2004 Classification: Unclassified Product: Mesa Version: git Platform: Other OS/Version: All Status: NEW Severity: normal Priority: medium Component: Drivers/Gallium/r600 AssignedTo: dri-devel@lists.freedesktop.org ReportedBy: aaalmosss@gmail.com
Whenever some new geometry appears (even for weapon projectiles), the framerate drops drastically for a short time. This is a frequent event, so the game becomes unplayable overall.
There is also a big preformance drop with the old compiler, when several players get gibbed at once (happens frequently on as-convoy), but with the llvm compiler this is much worse.
I'm not an expert on this, but it seems as if a new vertex shader would be compiled for each vertex array submitted, and the llvm compiler is an order of magnitude slower.